SATEL XPRS RADIO ROUTER
RADIO UNIT
SATELLAR XT 5R AND XT 5RC
USER GUIDE VERSION. 1.8
RU
USER GUIDE
Copyright © 2019 SATEL Oy
No part of this document may be reproduced, transmitted or stored in a retrieval system in any form or by any means
without the prior written permission of SATEL Oy. This document is provided in condence and must not be distributed
to third parties without the express permission of SATEL Oy.
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Contents
Important notice 6
Restrictions on use 7
Product conformity 8
Warranty and safety instructions 9
1. Introduction to the SATELLAR product family 10
1.1 Terms and abbreviations 14
2. Technical specications 15
3. Typical setup 19
4. Mounting 21
4.1 Mounting of the SATELLAR XT 5R and 5RC 21
4.2 Front cover 22
5. Interfaces 23
5.1 Serial data 24
5.1.1 RS-232 24
5.1.2 RS-485/422 interface 25
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5.1.3 RS-485/422 line length 26
5.1.4 Unit load 26
5.1.5 RS-485/422 termination 26
5.1.6 RS-485/422 connection/termination examples 26
5.1.7 Failsafe RS-485/422 termination 28
5.2 Radio 29
5.3 DC supply 30
5.4 Diagnostics, monitoring, changing settings 30
5.5 LED indicators 31
5.6 Function button 32
6. Data transmission 35
6.1 Basic mode with TX priority 35
6.2 Basic mode with RX priority 37
6.3 Basic mode with repeater 38
6.4 Source routing 38
6.5 Packet routing 41
6.5.1 Radio access control 43
6.6 Data ow control in basic and source routing mode 44
6.6.1 TX delay 44
6.6.2 Handshaking 44
6.6.3 Error control 46
6.6.4 Pause length 46
6.7 Link specic network settings with packet routing 47
6.7.1 Link specic QAM modulation 47
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6.7.2 Link specic Handshake and Retransmissions 48
6.8 Automatic QAM modulation with packet routing 49
6.9 Link specic QAM modulation and automatic QAM modulation settings 50
7. Settings 51
7.1 Network protocol modes 51
7.1.1 Station addresses and network ID 52
7.2 Radio settings 53
7.3 Serial connector conguration 54
7.4 Data port settings 55
7.5 Serial data ow control 56
7.6 Packet mode radio access control 57
8. Accessories 61
9. SATEL open source statements 62
9.1 AES Encryption 62
10. Troubleshooting 63
10.1 Error codes 63
10.2 Connection problems 67
11. Settings selection guide 68
11.1 Modem Settings 68
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All rights to this manual are owned solely by SATEL
Oy (referred to in this user guide as SATEL). All
rights reserved. The copying of this manual (with-
out written permission from the owner) by printing,
copying, recording or by any other means, or the
full or partial translation of the manual to any other
language, including all programming languages,
using any electrical, mechanical, magnetic, optical,
manual or other methods or devices is forbidden.
SATEL reserves the right to change the technical
specications or functions of its products, or to
discontinue the manufacture of any of its products
or to discontinue the support of any of its products,
without any written announcement and urges its
customers to ensure that the information at their
disposal is valid.
SATEL soware and programs are delivered ”as
is”. The manufacturer does not grant any kind of
warranty including guarantees on suitability and
applicability to a certain application. Under no cir-
cumstances is the manufacturer or the developer
of a program responsible for any possible damages
caused by the use of a program. The names of
the programs as well as all copyrights relating to
the programs are the sole property of SATEL. Any
transfer, licensing to a third party, leasing, rent-
ing, transportation, copying, editing, translating,
modifying into another programming language
or reverse engineering for any intent is forbidden
without the written consent of Satel.
SATEL PRODUCTS HAVE NOT BEEN DESIGNED,
INTENDED NOR INSPECTED TO BE USED IN ANY
LIFE SUPPORT - RELATED DEVICE OR SYSTEM
- RELATED FUNCTION NOR AS A PART OF ANY
OTHER CRITICAL SYSTEM AND ARE GRANTED NO
FUNCTIONAL WARRANTY IF THEY ARE USED IN ANY
OF THE APPLICATIONS MENTIONED.
Salo, Finland 2019
Important notice
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SATELLAR radio modem has been designed to
operate on 360-485 MHz, the exact use of which
diers from one region and/or country to another.
The user of a radio modem must take care that the
said device is not operated without the permission
of the local authorities on frequencies other than
those specically reserved and intended for use
without a specic permit.
SATELLAR is allowed to be used in the following
countries, either on licence free channels or on
channels where the operation requires a licence.
More detailed information is available at the local
frequency management authority.
Countries: AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI,
FR, GB, GR, HR, HU, IE, IL, IT, LV, LT, LX, MT, NL, NO,
PL, PT, RO, RU, SE, SI and SK.
Restrictions on use
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Product conformity
SATELLAR
SATEL Oy hereby declares that SATELLAR Radio Unit (referred to in this user guide as RU) radio modem
is in compliance with the essential requirements (radio performance, electromagnetic compatibility
and electrical safety) and other relevant provisions of Directive 2014/53/EU. Therefore the equipment is
labelled with the following CE-marking.
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Warranty and safety instructions
Read these safety instructions carefully before using the product:
– The warranty will be void if the product is used in any way that is in
contradiction with the instructions given in this manual, or if the housing of the
radio modem has been opened or tampered with.
– The radio modem is only to be operated at frequencies allocated by local
authorities, and without exceeding the given maximum allowed output
power ratings. Satel and its distributors are not responsible if any products
manufactured by it are used in unlawful ways.
– The devices mentioned in this manual are to be used only according to the
instructions described in this manual. Faultless and safe operation of the
devices can be guaranteed only if the transport, storage, operation and
handling of the devices is appropriate. This also applies to the maintenance of
the products.
– To prevent damage to device, both the radio modem and any terminal device
must always be switched OFF before connecting or disconnecting the serial
connection cable. It should be ascertained that dierent devices used have the
same ground potential. Before connecting any power cables the output voltage
of the power supply should be checked.
– It is possible to connect the device to an outdoor antenna or a cable distribution
system. In these cases, in order to conduct the possible over voltages due to
lightings to earth, the equipment should be connected to protective earth by
using the mounting screws of the device. This is a requirement in order to be in
compliance with the electrical safety regulations (EN 60950-1).
– To be protected against all veried adverse eects the separation distance of
at least 50 cm must be maintained between the antenna of SATELLAR radio
modem and all persons.
– Any radio link can susceptible to external interference and signal degradation by
its nature. Beacuse of that, the eects of possible interference mechanism and
the suicient back-up schemes must be taken into account in the system design
of the critical applications.
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1. Introduction to the SATELLAR product family
3
1. Introduction to the SATELLAR product family
SATELLAR is a new generation narrow band radio modem, which consists of separate units:
– Central unit (CU)
– Radio unit (RU)
Figure 1.1 SATELLAR product family:
1. SATELLAR XT 5RC with display:
Central unit (CU) with display and keypad + radio unit (RU)
2. SATELLAR XT 5RC without display:
Central unit (CU) without display and keypad + radio unit (RU)
3. SATELLAR XT 5R: Radio unit (RU)
Using SATELLAR, customers build their own independent radio data communication network.
This document presents the specications and the intended use of the RU. The properties of other units are
described in their own manuals. Reading them is necessary to understand the operation of the RU.
Data communication
SATELLAR operates either as a transparent radio link, essentially replacing a cable, for classic RS-232 /
RS-485 / RS-422 based protocols or as a wireless router in an IP-based network. When the RU is acting as a
router station in an IP network without any local Ethernet connection, it can be used as a standalone device.
In stations where a local Ethernet connection is needed it must be used together with a CU.
SA00057
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
1 2
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
3
TD
RD
PWR
STAT
RX
TX
CTS
RTS
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1. Introduction to the SATELLAR product family
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SA00066
TD
RD
PWR
STAT
RX
TX
CTS
RTS
Figure 1.2 SATELLAR XT 5R: The Radio unit (RU) is used as standalone device router station, where Ethernet is not
needed.
SA00067
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
5
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
6
Figure 1.3 SATELLAR XT 5RC with display (on down le), SATELLAR XT 5RC without display (on down right) include RU
and CU. These types are used, when a local Ethernet connection is needed.
Range
In the RU of the SATELLAR the communication range of a point to point link is typically longer than 10 km
in urban conditions (some obstacles in the line of sight), and longer than 20 km in line of sight conditions.
Signicantly longer range can be achieved, depending on radio conditions, antenna selection etc. The
range can be further extended also by using the radio repeaters.
Security
Data security is oen a concern when using radio communication. In the SATELLAR a 128-bit encryption
on the air-interface ensures privacy in the radio network. With QAM-radio also the 256-bit encryption is
supported.
Flexible and expandable
The SATELLAR concept has been designed to be exible and expandable both in terms of hardware and
soware functions. This can also be seen when using the RU alone.
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1. Introduction to the SATELLAR product family
3
Modulation method
There are two - dierent kind – of radio units, one that support FSK modulation and one that supports
QAM modulation. Apart from the modulation and channel separation both of the dierent radio units
operate similarly and possible dierences are described in this user guide. These two versions are called
FSK-radio and QAM-radio throughout this document. Several dierent modulation levels are oered for
both of these variants. If the customer requires a long-range radio connection he/she selects a low level
modulation. On the contrary, if a high data rate is the primary concern a high level modulation must be
selected.
Channel width
Channel spacings 12.5, 25 and 150 kHz are supported with FSK-radio and with QAM-radio unit supported
channel spacings are 6.25, 12.5 and 25 kHz. Those can be selected by changing soware settings – without
a need to modify the hardware.
FEC (Forward Error Correction) and interleaving
To extend the radio range in a noisy environment (at the expense of the data rate) a forward error correc-
tion algorithm (FEC) can be used with FSK-radio. The RU oers two dierent code rates for forward error
correction and it is used together with interleaving to minimize the eect of errors occurring in bursts.
Adjustable output power
RF output power is adjustable within steps dened at factory by manufacturer. Maximum factory set
output power can not be exceeded by customer.
NOTE: It should be noted that modulation (except for Link specic QAM modulation), channel spacing, and
FEC must be equal in the whole network.
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1. Introduction to the SATELLAR product family
3
Figure 1.4 Modular construction, mounting of the central unit CU
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1. Introduction to the SATELLAR product family
3
Abbreviation Full Name Description
NMS Network Management System SATEL NMS is a combination of features and rmware
running in SATEL modems, a communication
protocol and external soware, together allowing the
monitoring, management and administration of radio
modem networks consisting of SATEL devices.
SATBUS SATEL Serial Bus Bus used to interconnect dierent SATELLAR units, e.g.
the RU and CU.
FPGA Field Programmable Gate Array Supervises the board HW and operates as a gateway
between SATBUS and the MCU.
MCU Master Controller Unit Main processor of the RU, responsible for DATA
handling and control of the unit electronics.
DSP Digital Signal Processor Performs digital signal processing and radio channel
medium access tasks. Issues control commands and
monitor the operation of the radio part.
UART Universal Asynchronous Receive Transmit In standard use in SATELLAR.
Table 1.1 Terms and abbreviations
1.1 Terms and abbreviations
Here below are explained a few terms and abbreviations to help the reader of this manual in understand-
ing the basic concepts of SATELLAR.
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2. Technical specications
3
2. Technical specications
Common radio parameters
Frequency range 360 – 485 MHz (Ask the availability from manufacturer)
Tuning range MHz 45 / 50 (360 - 405/400 - 445/400-450/440 - 485 MHz)
Channel width FSK-radio: 12.5, 25, 150 kHz selectable by soware
QAM-radio: 6.25, 12.5, 25 kHz selectable by soware
Carrier frequency setting Frequency programmability in 6.25 kHz steps
Carrier frequency accuracy
(over temperature)
+/-1.0 ppm *)
Carrier frequency long term stability +/-2.0 ppm/3 years
Latency (in transparent mode) < 18 ms (25 kHz, serial port speed 19200 bits/s, over-the-air
encryption o, FEC o)
Duplexity Half-duplex
Modulation methods FSK-radio: 4-, 8- and 16-FSK
QAM-radio: 2-, 4-, 8-, 16-, 32- and 64-QAM
Forward error correction (FEC) O, code rate 0.67, code rate 0.5
NOTE! FEC not available with 16-FSK or with QAM modulation
Trellis coding Supported for 8-, 16-, 32- and 64-QAM modulation
Interleaving 8 x 96 bits
Over-the-air encryption FSK-radio: AES 128 bit (CTR-mode)
QAM-radio: AES 128 / 256 bit (CTR-mode)
*) At the factory
Transmitter parameters
Output power
FSK-radio unit
QAM-radio unit
0.1…5 W adjustable by soware, Steps: 0.1, 0.2, 0.5, 1, 2, 5 W
0.1…5 W adjustable by soware, Steps: 0.1, 0.2, 0.5, 1, 2, 5 W
(peak power ratings due to QAM modulation). Average power at max
peak power level is ~1W.
Adjacent channel power: Typically < -63 dBc (meas. method EN 300 113/EN 301 166)
Duty cycle ar max. power 100 % up to 60
o
C, 50 % up to 70
o
C
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2. Technical specications
3
Air speed
bits/s @12.5 kHz bits/s @ 25 kHz bit/s @ 150 kHz
4-FSK 9600 19200 115200
8-FSK 14400 28800 172800
16-FSK 19200 38400 230400
bits/s @6.25 kHz bits/s @12.5 kHz bits/s @25 kHz
2-QAM 4680 10080 20160
4-QAM 9360 20160 40320
8-QAM 14040 30240 60480
16-QAM 18720 40320 80640
32-QAM 23400 50400 100800
64-QAM 28080 60480 120960
Receiver parameters / FSK-radio
Sensitivity / dBm
Channel spacing / modulation BER
10E-3 10E-6 SNR* (minimum)
25 kHz / 19200 bps (4-FSK) -116 -108 20
12.5 kHz / 9600 bps (4-FSK) -119 -114 20
150 kHz / 115200 bps (4-FSK) -104 -97 20
25 kHz / 28800 bps (8-FSK) -108 -102 26
12.5 kHz / 14400 bps (8-FSK) -112 -105 26
150 kHz / 172800 bps (8-FSK) -96 -89 26
25 kHz / 38400 bps (16-FSK) -102 -94 32
12.5 kHz / 19200 bps (16-FSK) -104 -97 32
150 kHz / 230400 bps (16-FSK) -88 -82 32
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2. Technical specications
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Receiver parameters / QAM-radio
Sensitivity / dBm
Channel spacing / modulation BER
10E-3 10E-6 SNR* (minimum)
6.25 kHz / 4680 bps (2-QAM) -121 -118 11
12.5 kHz / 10080 bps (2-QAM) -118 -116 11
25 kHz / 20160 bps (2-QAM) -117 -114 11
6.25 kHz / 9360 bps (4-QAM) -118 -115 14
12.5 kHz / 20160 bps (4-QAM) -115 -113 14
25 kHz / 40320 bps (4-QAM) -114 -111 14
6.25 kHz / 14040 bps (8-QAM) -115 -112 17
12.5 kHz / 30240 bps (8-QAM) -113 -109 17
25 kHz / 60480 bps (8-QAM) -111 -108 17
6.25 kHz / 18720 bps (16-QAM) -111 -109 20
12.5 kHz / 40320 bps (16-QAM) -110 -106 20
25 kHz / 80640 bps (16-QAM) -108 -105 20
6.25 kHz / 23400 bps (32-QAM) -108 -106 23
12.5 kHz / 50400 bps (32-QAM) -107 -103 23
25 kHz / 10080 bps (32-QAM) -105 -102 23
6.25 kHz / 28080 bps (64-QAM) -105 -102 27
12.5 kHz / 60480 bps (64-QAM) -104 -100 27
25 kHz / 120960 bps (64-QAM) -101 -98 27
* SNR = Detector Signal to Noise Ratio
Common parameters
Power consumption
SATELLAR radio unit 17.9 W, 5 W transmission (TX mode)
7.3 W, 100 mW transmission (TX mode)
2.8 W, reception (RX mode)
Start time (from power o) < 2.5 s
Interfaces – power 2-pin plug with screw ange, pitch 3.5 mm, type Phoenix Contact MC
1,5/2-GF-3,5 THT, code 1937318
Interfaces – DTE RS-232/422/485 (TIA-574), D9 female
Up to 256 kbps
Interfaces – RF TNC female, 50 ohm
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2. Technical specications
3
Temperature ranges -25 - +55 °C, complies with the standards
-30 - +70 °C, functional
-40 - +85 °C, storage
Humidity < 95 % @ 25 °C, non-condensing
Vibration At least 10 – 500 Hz/5g without degradation in data transfer capability
Shock resistivity Dropping height 1 m, all directions
IP rating IP 52
DC input range +10.6 ... 30 V, nominal 12 V
Mechanical dimensions H × W × D
SATELLAR radio unit 130 × 55.5 × 76.5 mm
Mounting DIN rail (side or back) or directly on at surface
Weight
SATELLAR radio unit 680 g
Cooling
SATELLAR radio unit Convection cooling
Standards
Radio requirements FSK-radio: EN 300 113-1, -2, EN 302 561
QAM-radio: EN 300 113-1, -2, EN 301 166-1, -2
EMC
- radio unit
- central unit
EN 301 489-1, -5
IEC 61000-6-2, IEC 61000-6-4
Safety EN 60950-1
RoHS 2002/95/EC, 2002/96/EU, 2011/65/EU
Table 2.1 Technical specications of SATELLAR radio unit
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3. Typical setup
3
3. Typical setup
The gure below shows a typical setup when transferring data through the RU. When using the RU
together with the CU, the recommended minimum distance between antenna and the CU is 2 m in order
to avoid degradation of the receiver sensitivity due to radiated interference from the CU.
Setup is the same whether the radio unit used is FSK- or QAM-radio.
Figure 3.1 Transferring data through the RU, cabling
1.
RF cable
with TNC
male
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
RF
10.6-30
VDC
RS-485/
RS-232
2.
3.
Data cable
with D9
male
connector
Data
terminal
equipment
Power
supply
10.6-30VDC
17.9 W
SA00033
min
2 m
+ -
RU
CU
SATELLAR XT 5R
Radio unit only
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3. Typical setup
3
If the user wants to change/view settings the Data terminal equipment needs to be replaced by a PC. The
role of the port must then be changed to accept NMS messages. This can be done by pressing the function
button that is located below the RU LED indicators. The functionality of the button is described in chapter
5.5. When the type of the DTE interface is the standard RS-232, the port can also be congured so that it is
possible to use the Data terminal equipment and PC simultaneously (see chapter 7.4 for details).
TD
RD
PWR
STAT
RX
TX
CTS
RTS
Function button
SA00034
Figure 3.2 Location of the Function button
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4. Mounting
3
4. Mounting
4.1 Mounting of the SATELLAR XT 5R and 5RC
The SATELLAR XT 5R and 5RC can be mounted as follows:
– On a DIN-rail using SATELLAR specic DIN rail adapters (two pieces needed)
– With wall mount parts.
– The DIN rail adapters and wall mount parts have to be ordered separately.
Mounting is the same whether the radio unit used is FSK- or QAM-radio.
SATELLAR can be mounted directly on a at surface or to a DIN rail. DIN-rail mounting is possible either on
the backside of the stack of dierent SATELLAR units or on the other narrow side of each unit (the latter
case so that the LED indicators remain visible for the user).
Ruggedized
SATELLAR is constructed of die-cast aluminum to withstand the abuse typical to rough industrial environ-
ments. It operates over a wide temperature range and under severe vibration conditions to meet the
requirements of vehicular and process industry applications.
NOTE!
1. The equipment must be installed in restricted access location due to high touch
temperatures of metal enclosure.
2. The screen of coaxial antenna cable must be grounded to protect from over
voltages from outdoor antenna.
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4. Mounting
3
4.2 Front cover
When the radio unit is used as standalone it is possible to attach a front cover on the unit. See the gure.
SA00037
TD
RD
PWR
STAT
RX
TX
CTS
RTS
1.
TD
RD
PWR
STAT
RX
TX
CTS
RTS
2.
Figure 4.1 Attaching the front cover on the radio unit, when standalone.
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5. Interfaces
3
5. Interfaces
This chapter describes the external interfaces of the RU how its status can be monitored, how the settings
can be checked and modied. If you are using the RU attached with a CU with a display it is possible to see
and change settings by the graphical user interface of the CU. With the WWW interface of the CU it is also
possible to change and view the settings from a PC.
The meanings of RU related settings are described in chapter 7 of this manual.
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
SA00008
Figure 5.1 Display and keypad in CU
Figure 5.2 SATELLAR WWW interface Login view
Display
Keypad
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5. Interfaces
3
5.1 Serial data
The RU provides two ports, both using D9 female connectors. One port is intended for RS-232 com-
munication and hosts a full set of RS-232 signals including handshakes. The other port is intended for
RS-422/485 communication via dierential pair data signals. The RS-232 port can be used for data and / or
NMS communication. The RS-422/485 port can be used for data only.
Communication settings can be done by modifying user settings. SATELLAR Y-cable is needed for simulta-
neous RS-232 data and NMS connections in RS-232 port.
The serial interface uses asynchronous data format.
Supported serial port speeds, QAM:
- Transparent dataow –mode: 9600, 19200, 38400, 57600, 115200, 128000, 230400, 256000 bps
- Packet Routing –mode: 9600, 19200, 38400, 57600, 115200 bps
Supported serial port speeds, FSK:
- Transparent-, and Source Routing –mode: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 bps
- Packet Routing –mode: 1200*, 2400*, 4800*, 9600, 19200, 38400, 57600, 115200 bps
The following additional RS port settings can be used in Packet Routing –mode (unlike Transparent-, and
Source Routing –modes):
- Port Data Bits: 8
- Port Stop Bits: 1
*) Supported only in RS232
For other data port settings, please contact SATEL technical support.
5.1.1 RS-232
This interface can be used as data and/or NMS interface for RU. RS-232 interface port provides standard
D9 pin-out for DCE (TIA/EIA-574) as shown in the table below.
Pin nr Pin name Pin description
1 CD Explained in chapter 6.6.2
2 RD Receive Data: data traic from the RU to the DTE
3 TD Transmit Data: data traic from the DTE to the RU
4 DTR DTR function is not in use in the RU
5 SGND Signal Ground: the common voltage reference between the DTE and the RU
6 DSR Data Set Ready: an indication from the RU to the DTE that the RU is powered on
7 RTS Explained in chapter 6.6.2
8 CTS Explained in chapter 6.6.2
9 NC Not Connected
D9 SHIELD - Connected to device ground
Table 5.1 RS-232, pin-out of D9 connector
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5. Interfaces
3
5.1.2 RS-485/422 interface
The selection between RS-422 and 485 can be done by modifying the user settings. The RS-422/485 inter-
face features a galvanic isolation between the interface signals and the other electronics of the RU. The
interface also has a 5VDC output for external failsafe termination (see section on termination). RS-485-422
interface pin-out follows the standard for RS-485 Probus-DP, as far as possible.
The pin-out of the D9 connector in dierent operating modes is shown in the table below.
RS-485 RS422
Pin nr Pin name Pin description Pin description
1 NC - -
2 NC - -
3 B Receive/transmit data,
non-inverting
Transmit data, non-inverting
4 Y - Receive data, non-inverting
5 SGND Signal ground, isolated
6 5V_TERM Isolated 5 V for bus termination
7 NC - -
8 A Receive/transmit data,
inverting
Transmit data, inverting
9 Z - Receive data, inverting
D9 SHIELD - Connected to device ground (non isolated)
Table 5.2 RS-485/422, pin-out of D9 connector
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3
5.1.3 RS-485/422 line length
The RS-485/422 specication determines the maximum theoretical line length up to 1200m. For longer
line legths dedicated repeaters should be used. Signal loss and reections due to improper cables or
improper termination may result to reduced maximum usable line length.
5.1.4 Unit load
In RS-485 specications the RS-485 receiver input impedance is specied to be larger than or equal to 12
kOhm. This 12 kOhm impedance equals to one unit load. RS-485 specication species also the capability
to utilize up to 32 unit loads. In this serial interface module the RS-485 receiver has 96 kOhm impedance
which is 1/8 of the unit load.
This meands that having bus load of 1/8 of the specied unit load (12 kOhm) allows up to 256 devices (i.e.
nodes) to be connected to the bus.
Unit Load Receiver Input Imped-
ance
Max. No. of Nodes
1 12 kOhm 32
1/2 24 kOhm 64
1/4 48 kOhm 128
1/8 96 kOhm 256
5.1.5 RS-485/422 termination
For reliable operation, the RS-485/RS-422 dierential pair needs to be terminated to known impedance
by placing a resistor equal to the cable impedance between the two wires of the signal pair. Termination is
needed to prevent waveform reections, which can cause data errors if there are long dangling connec-
tions (stubs) in the data line.
A terminating resistor should be placed at both ends of an RS-485/422 chain. For maximum reliability,
terminate at least one end of a cable using failsafe termination.
5.1.6 RS-485/422 connection/termination examples
Following examples represent the dierent general connections and terminations of RS-485 and RS-422
interfaces. Cables with twisted pair signal wiring shall be used for connections between units.
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5.1.6.1 RS-485: 2-wire connection (half duplex)
5.1.6.2 RS-485: 4-wire connection (full duplex)
5.1.6.3 RS-422: 2-wire connection (multidrop)
5.1.6.4 RS-422: 4-wire connection (2 units only)
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5.1.7 Failsafe RS-485/422 termination
When there is no data on the bus (no node is transmitting), the RS-4xx signal pair oats free. In principle
both signals (‘a’ and ‘b’) should be oating at the same potential. However, due to possible outside distur-
bances, this is not always the case.
According to the RS-4xx standard, the receiver interprets signals as either logic high or low depending on
the dierence in potential between a and b. A potential dierence of greater than 0.4 V is required for the
receiver to decide whether the signal is low or high. In practice most receivers make the decision at greater
than 0.2 V level.
The RS-485 receiver output is typically logical ‘1’ when the inputs are oating.
When a disturbance causes, the potential dierence to increase logic ‘0’ is easily detected. This is then
interpreted as a start bit by the receiver on the RS-4xx bus, resulting in bit errors or garbled extra characters.
Another method of error due to lack of failsafe termination is that once a node starts transmitting on the
line, the receiver which already senses a ‘0’, misses the transition from stop bit to start bit, needed to syn-
chronize a UART transmission. Thus the receiver in error will receive the rst data byte wrong, and depend-
ing on the number of stop bits and a pause between bytes on the line, might miss also the following bytes or
even an entire packet.
This is a potential error mechanism, which can be easily overcome by pulling the ‘a’ line high and the ‘b’ line
low by connecting the wires thru a series resistor to the desired potential.
Figure 5.3 Failsafe termination examples
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5.2 Radio
The RU has a TNC female RF connector with impedance of 50 ohms. The frequency range of the RU is
coded in the type designation, which can be seen on the label back of the RU. The details of this are
explained in chapter 8.
The RF frequency can be set in 6.25 kHz steps. The RU supports three dierent channel spacing settings
that can be selected by soware. For FSK-radio these are 12.5, 25 and 150 kHz, and for QAM-radio 6.25,
12.5 and 25 kHz. Also three dierent modulation methods are supported. For FSK-radio these are 4-, 8-
and 16-FSK and for QAM-radio these are 2-, 4-, 8-, 16-, 32- and 64-QAM.
The output power can be adjusted with steps 0.1, 0.2, 0.5, 1, 2 and 5 W. With for FSK radio these are con-
stant envelope values but with QAM-radio these power levels are peak values due to crest factor (the ratio
of peak values to the eective value) in QAM modulation. Crest factor varies between QAM modulation
levels and the dierence between peak power value and average power value can be in range of 6-9 dBm.
E.g. for 5 W (37dBm) peak power value, the average power level is ~1W (30dBm). It should be noted that
average values should be used when dening radio link budgets of a network.
Channel spacing together with the modulation method determines the air speed as claried in the techni-
cal specication in chapter 2. Air speed can be set independently of the data rate of the serial port.
The modulation method also aects the receiver sensitivity. The best sensitivity can be obtained by the
lowest level modulation, i.e. 4-FSK/2-QAM in SATELLAR XT 5R case. For typical sensitivities in dierent
conditions see the technical specication in chapter 2.
Another method to improve the sensitivity of the receiver is to use Forward Error Correction (FEC), this can
be used for SATELLAR XT 5R with 4- and 8-FSK modulations. This improvement eects the user data rate:
the air speed remains the same but the fraction of bits available for the user is as indicated by the code
rate of the FEC. The RU oers two dierent code rates, 0.67 and 0.5. For example, if 4-FSK is used with 25
kHz and the FEC is switched on with the code rate of 0.5 the user bit rate goes down to 9600 bits/s. The
eect of the FEC on the sensitivity depends on the code rate and the level of BER (Bit Error Rate) at which
the radio link is operating.
Changing of the modulation method or using FEC helps to improve the receiver sensitivity in noisy con-
nections, i.e. the bit errors are mostly evenly distributed over the entire transmission period. If the errors
happen in bursts these methods are not very eicient. For this reason the FEC is used together with the
interleaving method. This means that before transmitting the data from the DTE, the RU collects a certain
amount of data to the buer and rearranges it according to a certain rule. The receiver knows the rule and
recovers the original order of data bits. The receiver then sees the errors scattered and the FEC can cor-
rect the errors. It should, however, be noted that FEC and interleaving increase the latency and should be
avoided in transparent mode in cases where a low latency is a primary requirement.
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3
QAM-radio supports trellis coding with 8-, 16-, 32- and 64-QAM modulations which does not increase sym-
bol rate nor expand the bandwith. However it can introduce coding gain and thus improve the S/N ratio
compared to uncoded system. Trellis coding has eect on latency and it can be disabled if the low latency
is the primary concern. Trellis coding is enable by default.
5.3 DC supply
The DC connector of the RU is a detachable / lockable screw terminal. The DC voltage range is 10.6-30
V. The power supply used should be able to deliver at least 17.9 W of DC power. Please note that the RU
delivers DC power to the entire stack of SATELLAR units. So when using the RU together with CU the power
consumption of the entire stack must be taken into account when selecting the DC power supply.
5.4 Diagnostics, monitoring, changing settings
The settings of the RU can be viewed and changed by SATEL NETCO Design stack. The computer is then
connected to the serial connector of the RU and the connector must be congured to accept NMS mes-
sages. If the basic radio settings have previously been set locally it is also possible to establish a remote
connection to another RU and change and view the settings of that modem over-the-air.
When the RU operates together with the CU with a display and a keypad, the device settings can be
viewed and changed via the graphical user interface of the CU. Alternatively; the Web interface can be
used.
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
SA00008
Figure 5.4 RU together with Central Unit (CU) equipped with LCD display and keypad, the main views
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5. Interfaces
3
Figure 5.5 SATELLAR WWW interface Login view
Settings are described in chapter 7, serial data connector conguration especially in chapter 7.3, and the
use of the PC soware is described in its own documentation.
5.5 LED indicators
The RU provides eight LED indicators that are located on the other narrow side of the unit.
They are listed and described in the table below.
TD
RD
PWR
STAT
RX
TX
CTS
RTS
SA00042
PWR
STAT
RD
TD
CTS
RTS
TX
RX
Name Description
RX Receive data over radio
TX Transmit data over radio
RTS Request To Send; more details in chapter 6.6.2
CTS Clear To Send; more details in chapter 6.6.2
TD Transmit Data over the serial interface
RD Receive Data over the serial interface
STAT ON: power is on, the RU has been initialized and ready to operate
OFF: the RU is not ready to operate
PWR ON: power connected
OFF: power not connected
Figure 5.6 LED indicators
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5. Interfaces
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5.6 Function button
TD
RD
PWR
STAT
RX
TX
CTS
RTS
Function button
SA00034
Figure 5.7 Location of the function button
The function button is located below the LED indicators. By pressing the button you can restart or tempo-
rarily congure the serial data connector to accept NMS messages and thereby getting the RU accessible
by SATEL NETCO Design stack for viewing and changing the settings irrespective of the user settings.
Example 1:
The RU is connected with the CU and the user has selected the setting ‘MCU UARTs to SATBUS’ (see chap-
ter 7.3). Now both the data and NMS messages are assumed to ow between the RU and the CU, so there
is no connection at the serial data connector. Then the CU gets broken or is removed before changing this
setting. By pressing the function button it is possible to temporarily congure the serial data connector to
accept NMS messages, which means that the RU is accessible by SATEL NETCO Design stack. Thereaer
the settings can be viewed and changed irrespective of the serial connector conguration.
Example 2:
The RU is used in the transparent mode of data transmission (serial data connector conguration ‘Data
UART to radio D9 RD/TD’) and there is a temporary need to change or view settings using the CU. By press-
ing the function button it is possible to temporarily congure the NMS messages to ow between the RU
and CU.
The duration of the button pressing determines to which state the serial data connector is congured as
described in the table below. For the names of the LED indicators, see chapter 5.5. When the button is
released the LED indicators return to the normal state.
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TD
RD
PWR
STAT
RX
TX
CTS
RTS
SA00042
PWR
STAT
RD
TD
CTS
RTS
TX
RX
Figure 5.8 Function button operation by LED indication
Duration of Specic to
the press Indication LED HW variant Effect Typical use case
Less than 1s All the LEDs are
switched on
(1111 1111)
•
•
•
•
•
•
•
•
The serial data connector is
reset to the state dened by
the user (see chapter 7.3)
More than 1s The uppermost
LED (RX) is
s w i t c h e d o
(0111 1111)
•
•
•
•
•
•
•
•
The serial data connector is
deactivated, i.e. the user data
traic and NMS messages
ow internally between the
Radio and Central units
Serial port conguration other
than MCU UARTs to SATBUS
WITH CAN (see chapter 7.3).
Need to temporarily connect
the RU to the Central unit.
More than 2s The two
uppermost
LEDs are
switched o
(0011 1111)
•
•
•
•
•
•
•
•
NMS messages in RD and TD
lines (protocol RS-232), no
user data transfer.
NOTE! Does not take the
eect if CU is connected.
Serial port conguration:
Data UART to radio D9 RD/
TD (see chapter 7.3). Need to
temporarily congure the RU
using NMS from a PC.
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5. Interfaces
3
Duration of Specic to
the press Indication LED HW variant Effect Typical use case
More than 3s The three
uppermost
LEDs are
switched o
(0001 1111)
•
•
•
•
•
•
•
•
RU-xxxx00 NMS messages in RTS and
CTS lines, no user data
transfer
More than 4s The four
uppermost
LEDs are
switched o
(0000 1111)
•
•
•
•
•
•
•
•
User data transfer in RD and
TD lines (protocol RS-232),
NMS messages between the
Radio and Central units
Serial port conguration:
Data UART to radio D9 RD/
TD (see chapter 7.3). Need to
temporarily congure the RU
using NMS from the Central
unit. Normally this mode is
selected by conguring the
serial port as described in
section 7.3.
More than 5 s The lowest
three LEDs
remain
switched on
(0000 0111)
•
•
•
•
•
•
•
•
RU-xxxx01 NMS messages in RD and TD
lines (protocol RS-485), no
user data transfer
Serial port conguration: RS-
485 (see chapter 7.3). Need to
temporarily congure the RU
using NMS from a PC.
More than 6 s The lowest two
LEDs remain
switched on
(0000 0011)
•
•
•
•
•
•
•
•
RU-xxxx01 NMS messages in RD and TD
lines (protocol RS-422), no
user data transfer
Serial port conguration: RS-
422 (see chapter 7.3). Need to
temporarily congure the RU
using NMS from a PC.
More than 7 s The lowest
LED remain
switched on
(0000 0001)
•
•
•
•
•
•
•
•
No eect
More than 8 s All the LEDs
switched o
(0000 0000)
•
•
•
•
•
•
•
•
The RU is restarted and the
serial data connector is reset
to the state dened by the
user
Table 5.3 Function button operation
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6. Data transmission
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6. Data transmission
In order to transfer data, the RU must be congured to operate in one of the following modes
– Basic, TX priority
– Basic, RX priority
– Basic, repeater
– Source routing, master (supported with FSK-radio)
– Source routing, slave (supported with FSK-radio)
– Packet routing
– Link Based Modulation (supported with QAM-radio)
– Automatic QAM Modulation (supported with QAM-radio)
These are called network protocol modes. Basic mode with TX priority is the traditional transparent mode
of data transmission, where the RU is eectively replacing a cable between two Data Terminal Equip-
ments. In basic mode with RX priority the transmission is disabled as long as there is a reception ongoing.
In repeater mode the data received from the radio path is buered and then forwarded back to the radio
path. Repeater mode is used to extend the radio coverage.
Source routing (supported only with FSK-radio) is needed when the network topology is more compli-
cated than just a point-to-point connection between two stations (possibly added by a repeater station).
This mode requires polling type protocols with xed station address length and position in the message,
based on RS-232, -422, and -485.
Packet routing is typically in use when the RU is working together with the CU. The CU interfaces with the
DTE using the IP protocol stack and acts as an IP router. The RU is seen as a virtual network interface and
does not need to be especially congured for the IP traic. However, settings related to medium access
control (see explanation later in this chapter) must be done and routing tables must be lled. As explained
earlier, the RU can act as a radio router station without the CU also in cases where IP data is transferred.
Only when a local Ethernet connection is needed the CU must be used.
6.1 Basic mode with TX priority
When the RU operates in basic mode with TX priority, the Data Terminal Equipment (DTE) is connected to
the serial data connector (D9). Data transfer starts immediately when the rst byte of data comes from the
DTE and stops when the data ends. The RU does not store the data anywhere and does not rearrange it at
all. It just sends the data that it gets as input. The radio link between the two DTE is done without routers
or repeaters in between. This mode is a simple point-to-point connection where the connecting cable is
replaced by a radio link. The DTE is fully responsible for the traic control: it decides when to transmit,
interprets the incoming data for correctness and decides further transmission is needed.
36 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
6. Data transmission
3
The basic mode with TX priority oers the shortest possible latency – the time needed for a receiving DTE
to receive the rst byte of data from the instant the sending DTE has initiated the transmission. The fac-
tors aecting the latency in the RU are:
– Receive-transmit turn-around time: The RU is normally in reception mode, i.e.
listens to the radio channel. When it recognizes that the DTE wants to send data
it switches to transmission mode, which requires a certain time to happen in the
radio hardware.
– Delays in lters: Channel ltering both in the transmitter and the receiver
required to meet the radio standards (like EN 300 113) generates a delay in the
radio link.
– RF power ramp-up time: The RF power cannot be switched on extremely fast
because of the transient spectrum requirements of the radio standards.
– Synchronization: Aer the RF power ramp-up there must be a certain
synchronization sequence during which the receiver adjusts to the frequency
and timing of the transmitting radio. It then decides whether the received signal
is a valid transmission instead of an external interferer.
– In addition the factors aecting the latency are
– Forward error correction (only with FSK-radio): The principle of forward error
correction is to read a few bits to a data register and generate a codeword
based on a certain mathematical formula and the stored data bits. This at rst
generates some delay in the transmitter but especially in the receiver where a
longer bit sequence must be stored before being able to decode the incoming
codeword.
– Encryption in the radio path: The principle of encryption is to collect a certain
amount of data to a shi register and manipulate it according to a certain rule.
The process of encryption adds delay in the data ow and must be avoided in
the cases where low latency is the most important requirement.
– Trellis Coding (only with QAM-radio): Trellis coding is used to introduce coding
gain that brings benet for receiver sensitivity especially in noisy environment.
This is causing some decoding delay which can introduce additional latency.
Trellis coding can be set to OFF when latency is the most
important requirement.
Strictly speaking the last two factors violate the principle of transparent data transmission (no modica-
tions to the content of the data). However, this is more or less a matter of denition. More important is to
understand that switching these on aects the latency and must not be done in applications where low
latency is a critical requirement.
To use the RU in basic mode with TX priority:
– Congure the data port settings as required by the used data transmission
protocol (data rate, number of data bits, number of stop bits, parity).
– Set the network protocol mode to basic, TX priority
– If required modify the pause length parameter (see chapter 6.6.4. for explanation)
– Set the serial port conguration so that Data UART goes to Radio D9 RD/TD (see
chapter 7.3 for explanation)
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6. Data transmission
3
– Set all the radio parameters as required (unless already set in the factory): radio
frequency, channel spacing, RF output power, modulation method, forward
error correction (FSK)/trellis coding (QAM) and encryption.
6.2 Basic mode with RX priority
Basic mode with RX priority is similar to TX priority. The dierence is in how the RU reacts to the incom-
ing data from the DTE: when the priority is TX the transmission is started without delay even when there
is a reception ongoing while in RX priority the transmission is started just aer the reception has been
completed.
An example of how to use priority settings in a simple network is shown in the gure below.
SA00043
No radio
coverage
between B
and C
Station A
(RU+CU)
Priority TX
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Station B
(RU)
Priority RX
TD
RD
PWR
STAT
RX
TX
CTS
RTS
Station C
(RU)
Priority RX
TD
RD
PWR
STAT
RX
TX
CTS
RTS
Figure 6.1 Priority settings in a simple network
Station ‘A’ has a radio link to stations ‘B’ and ‘C’. It sends control commands to these. Stations ‘B’ and ‘C’
respond by sending either status information or acknowledgement messages. They cannot hear each
other’s radio transmissions. Control commands from station ‘A’ are of high priority, so station ‘A’ needs to
start sending despite it has an incoming message. Therefore station ‘A’ is set to priority TX while the others
are set to priority RX.
Priority settings help if the radio coverage is as described in the gure above, i.e. if station ‘B’ and ‘C’ can-
not hear each others’ transmissions. Consider a situation where station ‘B’ is sending to ‘A’ and ‘A’ then
needs to send a high priority message to station ‘C’ while it still has reception ongoing from ‘B’. Due to
priority setting to TX it is possible but if stations ‘B’ and ‘C’ are within each others’ radio coverage the two
simultaneous messages from ‘A’ and ‘B’ collide at ‘C’ and therefore the message from ‘A’ is probably not
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6. Data transmission
3
received correctly. This kind of situation cannot be solved with priority settings but needs a more com-
plicated handshaking procedure, which is explained in chapter 6.6.2. Priority settings help the important
messages get through but must be used carefully keeping in mind that the stations set to priority RX may
not be within each others’ radio coverage.
6.3 Basic mode with repeater
Basic mode with repeater is used to extend the radio coverage by adding one RU operating in this mode
between two basic mode RUs as described in the Figure 6.2.
Figure 6.2 Basic repeater mode
RU ‘C’ stores all the data it receives and then forwards it to the radio path. There are no station addresses
in the RU, i.e. the DTE, which just sent data gets it back aer a while from the repeater station. Therefore
the DTE must be able to disregard these messages.
6.4 Source routing
Source routing is supported with FSK-radio.
When two or more repeaters are used it is necessary to use addresses to route the data. This is because
otherwise the repeaters would send the same messages to each other again and again in the network.
When using source routing the radio stations are forwarding only the data that belongs to them, not all the
data they hear in the network. The name source routing comes from the fact that only one station in the
network can be used as an entry point, the source, for the routing data. This station is called a master and
the other stations are slaves. Network topology is created with SATEL NETCO Design stack and sent to the
master station, which then includes the routing data in the messages to the slave stations. The following
picture claries the situation.
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6. Data transmission
3
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
Radio unit D
(RU)
Slave mode,
address: 2
SA00044
Radio unit E
(RU)
Slave mode,
address: 3
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Radio unit B
(RU+CU)
Slave mode,
address: 4
DTE B
Radio unit C
(RU+CU)
Slave mode,
address: 5
DTE C
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Radio unit A
(RU+CU)
Master mode,
address: 1
DTE A
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Figure 6.3 Routing between master station and slave stations
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6. Data transmission
3
RU ‘A’ acts as a master station in this network and has the following routing table in the memory:
DTE Route
B 2, 3, 4
C 2, 3, 5
When DTE ‘A’ sends data e.g. to DTE ‘B’ the RU ‘A’ picks the address of the DTE ‘B’ from the message and
then determines which route to use. In this example the route is the upper one, i.e. 2, 3, 4. Before send-
ing the message the RU ‘A’ adds the route to the start of the message and in addition tells that the next
receiver is station ‘D’ with address 2. All the other stations (not in the gure) except for ‘D’ that possibly
hear the message ignore it. Station ‘D’ picks the message, copies the routing data, and modies the next
receiver indicator to point to station ‘E’ with address 3. The same procedure is repeated through the whole
chain until the message reaches the destination DTE, ‘B’ in this example.
When DTE ‘B’ replies to ‘A’ the message goes through the router chain in an opposite direction. For exam-
ple, when the reply message reaches station ‘E’, that remembers the route and forwards the message
indicating that the next receiver is station ‘D’. The route remains valid as long as the reply message has
reached the original sender. For the next message the routing information must be sent again.
How the DTE includes the address data in the message depends on the used communication protocol.
Adaptation to dierent protocols is done by the protocol lters that are available in SATEL NMS PC so-
ware. These lters tell to the RU how to interpret the incoming message. No special protocol support is
needed in the RU rmware.
As explained earlier, source routing is used in polling type protocols with xed station address length and
position in the message, based on RS-232, -422, and -485.
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6. Data transmission
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6.5 Packet routing
An important limitation in the implementation of the source routing is that there is no radio access control
behind, i.e. all the traic must be originated by the master station: DTE ‘A’ sends a query message to DTE
‘B’ that then replies using the same radio route in the inverse order. Thereaer ‘A’ can send the same
query to ‘C’ which also replies. In this way there occur no collisions on the radio channel. This amount of
functionality is enough for the so-called polling protocols. A drawback, however, is that slave stations can-
not generate any messages independently, e.g. automatic status reports from the slave stations are not
possible. Another drawback is that the slave stations cannot communicate with each other.
The mentioned drawbacks can be overcome by using the RU in packet routing mode. This mode allows
each station to be in connection with every other station and there is no master station, which initiates all
the traic in the network. Also, there is a radio access control to prevent data packet collisions in the radio
path. The radio access control is briey explained in chapter 6.5.1. The routing table is constructed so that
each unit has one or more neighbor (next hop) addresses where to route the incoming data next. For every
neighbor address are listed the addresses of the stations that are found behind it. Each station selects
the correct neighbor station according to the nal destination address and thereaer the data proceeds
hop by hop towards the destination. As an example is presented how the routing table looks like for the
network topology seen in the gure on page 42.
The routing table is the following:
Radio Unit Next hop Addresses be-
hind
A 2 3, 4, 5
B 3 1, 2, 5
C 3 1, 2, 4
D 1 -
3 4, 5
E 2 1
4 -
5 -
In this example the routing is very simple for RU ‘A’, ‘B’, and ‘C’ because they have only one possible next
hop regardless of the nal destination. Units ‘D’ and ‘E’, on the contrary, must select between multiple
alternatives.
Primarily, packet mode routing is used when transferring data over IP. This requires a CU to be connected
together with the RU, except for the radio router stations where the RU can operate alone. How the IP
addresses are congured for IP transmission is explained in the CU user manual.
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6. Data transmission
3
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
Radio unit D
(RU)
address: 2
SA00045
Radio unit E
(RU)
address: 3
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Radio unit B
(RU+CU)
address: 4
DTE B
Radio unit C
(RU+CU)
address: 5
DTE C
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Radio unit A
(RU+CU)
address: 1
DTE A
TD
RD
PWR
STAT
RU-145000
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
CU-1U2100
OK
Figure 6.4 Routing example
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6.5.1 Radio access control
The purpose of radio access control is to prevent the data packets to collide with each other on the radio
channel. This is particularly important in IP data transmission where the data packets are sent forward
whenever there are any to be sent. In Ethernet there is a collision avoidance algorithm in use. However, it is
strongly related to the fact that the network is built by using cables, i.e. all the stations can detect whether
there is traic on the line or not. Particular to the radio transmission is the presence of the so-called
hidden terminals: the terminals, which are transmitting without every other terminal in the network to be
able to detect that. The main purpose of the algorithm implemented in the RU is to provide a collision free
operation also in the presence of hidden terminals. The algorithm is called CSMA/CA (Carrier Sense Multi-
ple Access/Collision Avoidance) and is based on transmitting handshaking signals (RTS, CTS) between the
stations. A pre-requisite for the algorithm to work is that each station in the network has an address and
that there is a kind of routing table in use. The routing table tells each individual station which neighboring
station to listen to and to which station to send data.
There are a few settings in the RU that controls the operation of the collision avoidance algorithm. Those
are set in the factory so that the algorithm should perform well at the eld as such. However, to reach
the optimum performance for a particular use case the following properties of the network should be
considered.
– Network topology: Are there only point-to-point connections in the network or
are there one or more radio routers in use? If there are routers in the network, all
the stations must remain silent for a while aer each transmission, in order to give
a possible radio router station a privilege to forward the message. By telling each
of the RU that there are only point-to-point connections in the network, helps in
saving this additional waiting time and thus increasing the data throughput. If the
user application handles the data retransmission there is a fast mode setup which
does not have the handshaking feature. It has the fastest data throughput but
the tradeo is that the data packets collide more oen and the hidden terminal
rejection feature is switched o. See chapter 7.6 for more information.
– Retransmissions at the radio protocol level: There might be retransmissions
at the higher protocol layers (e.g. TCP) irrespective of this setting. Normally,
retransmissions at the radio protocol level should be on if the data goes
through one or more radio routers or if the higher protocol layers do not include
retransmissions.
– Back-o counter: This denes the time how long a station must wait before
starting a transmission in the case the radio channel is reserved. If the network is
small, the back-o counter can be low because the probability of collisions is low.
As the size of the network increases the back-o counter should be higher. The
correct value should be found experimentally based on the number of stations and
the amount of traic.
– Signal threshold: QAM: Adjustable in the range of -80 … -110 dBm. In Packet
Routing mode, radio delays the TX for radio interface for 10ms if radio signal
higher than the set Signal threshold trigger value is recognized. FSK: Adjustable
in the range of -80 … -127 dBm. Eects only to the CD line output in the serial
communication mode.
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6. Data transmission
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– Data reception can not be blocked with Signal Threshold setting.
– NOTE! The Fast Mode selection is not available with 150 kHz channel.
6.6 Data ow control in basic and source routing mode
In this chapter is described what ways there are available to add control to the data ow in basic mode.
6.6.1 TX delay
TX delay can be used in a situation where a certain master station sends queries as broadcast messages
to many sub-stations. To prevent the replies from the sub-stations to collide at the master station, you can
set dierent TX delay values to each of the sub-stations. This means that a sub-station does not reply to
the query until the TX delay period has been expired. TX delay is xed, i.e. the maximum length of the reply
message must be approximately known at the network conguration phase in order to really avoid colli-
sions at the master station. TX delay can be considered as a primitive time-slot mechanism.
6.6.2 Handshaking
The handshaking lines of the serial data interface can be used to control the data ow from/to the RU.
There are three dierent control lines for this purpose, namely CTS, RTS, and CD lines.
6.6.2.1 CTS (Clear To Send)
The CTS line is normally in the active state, which means that the RU is ready to accept data from the DTE.
When the RU sets the line to the inactive state the data transfer from the DTE to the RU is not possible.
There are four alternative criteria for the user to select when the CTS line goes to the inactive state. These
are explained in the table below:
Selection Description
Clear to send Goes to the inactive state in the following cases:
1) Data reception is ongoing.
2) A pause (packet end) has been detected in the transmitted data
and there is still data in the transmission buer. The line shis back
to the active state when the RU has nished the transmission.
3) Transmission buer is in danger of overowing.
TX buer state Goes to the inactive state only when the transmission buer is in
danger of overowing. This happens typically in cases where the
data rate of the serial interface is higher than the air speed.
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6. Data transmission
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RSSI
threshold
Goes to the inactive state only when the received signal is stronger
than the pre-dened threshold value.
Always on The line is always in the active state.
Table 6.1 CTS line in inactive state
6.6.2.2 RTS (Request To Send)
The RTS line is normally in the active state, which means that the DTE is ready to accept data from the RU.
When the DTE sets the line to the inactive state the data transfer from the RU to the DTE is not possible.
There are three alternatives for the user to select how the RU reacts when the RTS line goes to the inactive
state. These are explained in the table below:
Selection Description
Flow control The RU continues the reception but buers the received data
until the RTS line goes back to the active state. This is typically
used in situations where the DTE is too slow to receive all the
data. The size of the receiver buer is about 1.6 kBytes but
must be checked for each particular HW and SW version if
seen critical in the application.
Reception control The RU stops the whole reception.
Ignore The status of the RTS line is not followed at all.
Table 6.2 RTS line in inactive state
6.6.2.3 CD (Carrier Detect)
The CD line is an indicator from the RU to the DTE that a signal has been detected on the radio channel.
There are three alternative criteria for the user to select when the line goes to the active state. These are
explained in the table below:
Selection Description
RSSI Threshold Active when the received signal is stronger than the pre-
dened threshold value.
Data on channel Active when there is a data reception ongoing.
Always on The line is always in the active state.
Table 6.3 CD line in inactive state
It depends on the application how the DTE reacts to the information provided by the CD line.
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6.6.3 Error control
For error checking purposes there is a mechanisms in the RU: cyclic redundancy check (CRC).
Cyclic redundancy check is possible for the user to switch ON, Partial and OFF. When CRC = ON the trans-
mitter calculates the checksum based on the whole data stream, which has been received. If the check
is ok, the data is sent to UART. A drawback in this is that the latency increases by the transfer time of the
whole packet. In some applications it may be useful to use CRC=Partial, in this case transmitter is working
on block-by-block basis so that once a block of data is checked to be ok, it is transmitted immediately
and then next data block is checked. With CRC=Partial there’s a possibility of latter blocks be wrong in
which case the transfer is stopped (but all so far transferred data is still correct). If CRC Check is OFF, data
transfer is stopped once CRC is noticed to be wrong but there may have been erroneous data sent to UART
before this.
The basic guidelines how to use the error control features are the following:
– When it is important to be sure that the data is correct but the latency is not critical:
switch the CRC ON.
– When every received character being correct it is not critical and the latency is
critical: switch the CRC OFF.
6.6.4 Pause length
Pauses are used to separate two messages from each other at the serial interface. A typical pause length,
which is interpreted, as the end of the message is three characters. However, non-real time operating sys-
tems used in many DTE easily add random pauses in the data stream. Those pauses are then seen as mes-
sage breaking points in the RU. To overcome this situation pause length parameter has been introduced
and must be set higher than the worst-case pause in the data stream. The data stream from the DTE must
then take this setting into account: the RU does not recognize the pauses that are shorter than the value of
the pause length parameter.
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6.7 Link specic network settings with packet routing
With QAM-radio it is possible to adjust modulation level, handshake and retransmission also for each
radio link in the network separately. These settings can be done either via CU WEB GUI or by using
SATEL NETCO Design stack.
6.7.1 Link specific QAM modulation
Typically modulation settings must be the same throughout the network. With QAM-radios it is pos-
sible to enable link specic modulation mode which makes it possible to adjust each radio link with
a best usable modulation level. Same modem can communicate with neighboring modems using
dierent modulation which is selected based on the requirements for the specic radio path.
For example: A network consists of six modems using 25kHz channel width: modem A which is mas-
ter and remote modems B, C, D, E and F so that the distance between master modem A and modems
B, C and D is relatively short, distance between A and E is longer and nally connection between A
and F is close to maximum range that can be achieved. In order for connection to be robust it is man-
datory to use modulation level of 2-QAM for the connection between master modem A and remote F.
If all of the network would be having the same modulation scheme, the only solution would be
selecting 2-QAM for the whole network thus setting a maximum airspeed ~20.2 kpbs for every radio
link. However, with link specic QAM modulation it is possible to manually select e.g.
64-QAM for links A - B, A - C and A - D -> ~121 kbps
16-QAM for A - E ->~ 80.6 kbps
2-QAM for A - F -> ~ 20.2 kbps
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6. Data transmission
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This makes it possible to enhance the overall performance of the network as most of the modems can
use higher airspeed.
Controlling link specic QAM modulation for each radio link can be done either from CU WEB GUI or
using SATEL NETCO Design stack. By setting Link Specic Modulation to “Manual”, each radio link can
be set for best suitable modulation level: 2-/4-/8-/16-/32-/64-QAM. It is possible to set same link so that
Modem A is having 64-QAM towards Modem B while Modem B is having 32-QAM towards modem A but
typically it is recommended to set both modems to use the same modulation level as in general the
radio path is having symmetrical characteristics.
Even when link specic modulation is set to “Manual” the modems are still having basic modulation
setting dened by “modulation” setting. This basic modulation is used for handshaking and acknowl-
edge messages even though the data transmission is done with the modulation level that is link spe-
cic. Link specic modulation should not be lower than the basic modulation. This is due to possible
network performance degradation which could occur if some of the modems would not hear each
other and thus transmitting over other radio traic causing collisions.
6.7.2 Link specific Handshake and Retransmissions
Similarly to link specic QAM modulation, it is possible to set also Link Specic Handshake/Link Spe-
cic Retransmissions modes ON which enables selection of these settings for each link. Link specic
Handshake/Retransmissions are eective only if network level Handshake/Retransmission are set to
OFF. As with handshake and retransmission in general - Handshake ON/Retransmissions ON selec-
tion makes radio transmissions more reliable with cost of extra delay due to RTS/CTS protocol or the
actual retransmission, but with link specic handshake/retransmissions the network can be optimized
so that those connections that are reliable or less prone to hidden terminal cases can be le without
handshake/retransmissions thus making these connections faster.
Adjusting these values depends on the network and require understanding of each of the radio links.
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6.8 Automatic QAM modulation with packet routing
Link specic modulation can also be set to “Auto” mode which let the modem decide the selected
modulation level for each link based on radio path characteristics. These radio path characteris-
tics are deduced from the Signal To Noise ratio (SNR) that the device is detecting. Automatic QAM
modulation is dynamically selecting the best modulation level for each individual data transmis-
sion based on information it receives from the modem that is on the opposite side of the radio link.
In order for automatic modulation to function properly the radio traic needs to have continuous
nature and also bidirectional as the information about the radio link quality is transferred via normal
radio traic. If the radio traic is otherwise unidirectional Handshaking should be set to ON.
As with link specic modulation in general, the network will have a basic modulation level set by
the “modulation” selection. It should have a value that is safe for all possible cases for the whole
network as the automatic modulation will use it as lowest possible modulation level.
The automatic protocol to set the modulation is as follows for Modem A <--> Modem B case (start of
the transimission):
1. Modem A transmit to modem B using basic modulation
2. Modem B answers back to modem A using basic modulation
3. Modem A transmit to modem B with highest modulation level suitable
4. Modem B answers back to modem A with highest modulation level suitable
Thereaer every transmission is adjusted based on previous response between modems A and
B and highest suitable modulation level is used. If there are changes in radio path characteristics
every data package may have dierent modulation level.
In typical cases automatic QAM modulation selection works without further adjustment, but if
needed it is possible to set “Auto QAM SNR Level Adjust” value from -5 to +20 dB and thus control
how the modulation level is set. By setting a positive value it possible to move the selection level for
more pessimistic value (while making the connection slower) so that each +3..+4 dB change equals
approximately one modulation level (64-QAM 32-QAM or 16-QAM 8-QAM etc.). By selecting nega-
tive value automatic QAM modulation is set higher than in normally would and thus the connection
will be that much faster. It is worth noting that negative value may cause connection to be totally
lost if the radio path can’t work properly with this higher modulation level. This setting can also be
used in oice-table type testing if the SNR value stays high even when the radio signal strength goes
very low e.g. by using attenuators in noise free environment.
Automatic QAM modulation can’t be used together with manual link specic modulation i.e. auto-
matic mode should be selected for the whole network.
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6.9 Link specic QAM modulation and automatic QAM
modulation settings
Selection Description NMS ID
Modulation
Link Specic
Modulation
Link Specic
Handshake
Link Specic
Retransmissions
Auto QAM SNR Level
Adjust
Set the modulation level for whole network. If Link Specic
Modulation is used this set the basic modulation level.
1.1997
Selects the used modulation method against neighboring
radios. OFF = modulation is same for every neighbor and
follows the value in “Modulation”. Manual = Modulation can be
set dierently to each neighbor as described in Central Units
user manual. Auto = Modulation is adjusted automatically
based on detected signal quality.
1.2045
OFF = Handshaking selection is same for all neighboring radios
and follows the value in “Handshake”. ON = Handshaking
can be selected dierently for each neighbor as described in
Central Unit user manual.
1.2046
OFF = Retransmission selection is same for all neighboring
radios and follows the value in “Retransmissions”. ON =
Retransmissions can be selected dierently for each neighbor
with Packet Routing table/Link quality selection.
1.2047
Set the oset to Automatic QAM modulation so that positive
values will cause device to use lower modulation than normally
selected based on detected SNR level. Negative values will
cause selecting higher modulation than normally selected.
1.374
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7. Settings
As mentioned in chapter 5.4 settings can be viewed and changed by SATEL NETCO Design stack or by the
user interfaces of the CU. Settings have been described in earlier chapters in conjunction with the overall
descriptions of the dierent functionalities. Here below is presented a summary of all the user related
parameters and how they are organized in groups.
7.1 Network protocol modes
As explained in the beginning of chapter 6 the RU can be congured to operate in the following network
protocol modes:
– Basic, TX priority
– Basic, RX priority
– Basic, Repeater
– Source Routing-Master (supported with FSK-radio)
– Source Routing-Slave (supported with FSK-radio)
– Packet Routing
Figure 7.1 Network Protocol Mode settings view; WWW interface
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7. Settings
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Figure 7.2 Modem Settings, Network Protocol Mode; by CU interface
7.1.1 Station addresses and network ID
If the RU is congured to operate either in source or packet route mode, it must be given an address. The
address is freely selectable between 1 and 4093, see Figures 7.1 and 7.2.
The network ID is used to distinguish the dierent closely located networks from each other. The network
ID is a string with maximum length of eight characters.
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7.2 Radio settings
RX Frequency RF frequency of the receiver in MHz, e.g. 451.106250 MHz: can be adjusted by a numeric
editor.
TX Frequency RF frequency of the transmitter in MHz, e.g. 451.106250 MHz: can be adjusted by a numeric
editor.
RF Output Power RF output power in mW. Adjustable between 0.1 – 5W. (With QAM-radio these are peak
values)
Signal Threshold Received signal threshold level used in handshaking and in packet mode medium access
control (chapters 6.6.2 and 6.5.1).
Over-the-Air Encryption Can be either OFF or ON. In addition AES128/AES256 can be selected.
Forward Error Correction Can be selected from a predened list of OFF, rate 67 %, and rate 50 %. Forward error
correction is used together with interleaving. See chapter 5.2 for more information.
Trellis Coding Can be set ON or OFF. See chapter 5.2 for more information (only with QAM-radios)
Channel Spacing FSK-radio: 12.5, 25, 150 kHz. QAM-radio: 6.25, 12.5, 25 kHz
Air Speed Can be selected from a predened list that depends on the selected channel spacing
and available modulation methods as explained in chapter 5.2. If the channel spacing is
changed the air speed needs to be changed as well.
Table 7.1 Modem Settings, Radio
Figure 7.3 Radio settings view; WWW interface
Figure 7.4 Modem Settings, Radio; by CU interface
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7.3 Serial connector conguration
The setting selected here becomes active whenever the RU is switched on. If the setting has been changed
by pressing the function button as described in chapter 5.6, this setting becomes active again when the
function button is pressed for less than a second. The conguration options are the following:
Radio unit with RS-232 interface with handshaking
Can be selected from a predened list of:
– MCU UARTs (Data and NMS) to SATBUS (normal setting when RU is permanently
operating with the CU).
– Data UART to Radio D9 RD/TD (standard RS-232 interface, normal setting when
the RU is operating in transparent mode of data transfer).
– Data UART to Radio D9 RD/TD – NMS to DTR/DSR (RS-232 data transfer using
handshaking, need to simultaneous monitoring using NMS).
– Data UART to Radio D9 RD/TD – NMS to RTS/CTS (RS-232 data transfer without
handshaking, an alternative to the previous setting).
– Data UART to Radio D9 RD/TD – NMS to SATBUS (standard RS-232 interface,
need to use the CU as a conguration tool).
– MCU UARTs (Data and NMS) to SATBUS with CAN.
Radio unit with RS-422/-485/-232 interface without handshaking
Can be selected from a predened list of:
– RS-422
– RS-485
– RS-232 (RD, TD & SGND only)
In the latter model it is not possible to have simultaneous data and NMS. However, the serial connector
can be congured to accept oline NMS messages as explained in chapter 5.6.
Figure 7.5 Serial Connector Congurator view; WWW interface
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Figure 7.6 Modem Settings, Serial Connector Conguration; by CU interface
7.4 Data port settings
Limitations applies only to Transparent-, and Source Routing –modes. See further details from section 5.1
Serial data, page 24.
Data rate 1200*, 2400*, 4800*, 9600, 19200, 38400, 57600 and 115200 bits/s
*) Supported only in FSK models
Number of data bits 8 bits
Parity No Parity Check, Even, and Odd
Number of stop bits 1 bit
Table 7.2 Modem Settings, Data Port Settings
Figure 7.7 Data Port Settings view; WWW interface
Figure 7.8 Modem Settings, Data Port Settings; by CU interface
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7.5 Serial data ow control
TX delay 0 – 65535 ms. See chapter 6.6.1 for more details.
Error control CRC: ON or OFF. See chapter 6.6.3 for more details.
Maximum number of accepted errors: See chapter 6.6.3 for more details.
Handshaking lines CTS: Can be selected from a predened list of Clear to send, TX buer state,
RSSI threshold, and Always on. See chapter 6.6.2 for more details.
RTS: Can be selected from a predened list of Flow control, Reception
control, and Ignore. See chapter 6.6.2 for more details.
CD: Can be selected from a predened list of RSSI threshold, Data on
channel, and Always on. See chapter 6.6.2 for more details.
Pause length 3 – 255 bytes. See chapter 6.6.4 for more details.
Table 7.3 Modem Settings, Serial Data Flow Control
Figure 7.9 Serial Data Flow Control view; WWW interface
Figure 7.10 Modem Settings, Serial Data Flow Control; by CU interface
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7.6 Packet mode radio access control
Packet mode radio access control is briey explained in chapter 6.5.1.
Feature Explanation Sub unit NMSID
Network topology *)
/ Handshake *)
FSK models (Network Topology)
Point to point **
)
-mode: Recommended for the radio
networks where all the radio modems can reach each other and
the data collision avoidance is required to the radio interface.
Data retransmissions can be set ON/OFF at radio layer. With
RTS+CTS radio layer handshaking function.
0 1.430
Repeater -mode: Recommended for the radio networks
where all the radio modems can’t reach each other directly.
Data retransmissions can be set ON/OFF at radio layer. With
RTS+CTS handshaking function. Longer CTS reply at the
receiving radio, which is received in hidden terminal cases
where part of the radio network can’t receive the original RTS
message.
Fast mode –mode: only for radio networks with limited
amount of devices, where anti collision in the air interface
is taken into account in other part of the system. No data
retransmissions in the radio layer, no handshaking for the radio
layer.
Radio layer handshaking done always with 2FSK radio
modulation regardless of the user selected air rate. Radio layer
handshaking not displayed with TX/RX led indicators.
QAM models (Handshake)
HS OFF –mode: Notication of transmission to begin. Radio
layer handshaking: CTSS > DATA > ACK (if Retransmissions
enabled in transmitting radio).
HS ON –mode: Notication of the transmission to begin is
approved by the receiving radio layer handshaking: RTS -> CTS
-> DATA -> ACK (if Retransmissions enabled in transmitting
radio). RTS retransmissions always enabled. CTS message is
received also in other radio routers in the radio network for
”hidden terminal” cases, where part of the radio network can’t
receive the original RTS message.
Handshaking in the radio layer done always with selected QAM
modulation. Data retransmission in the radio layer possible
in both cases. Handshaking messages include the “channel
reserved” information. Radio layer handshaking displayed with
TX/RX led indicators.
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Retransmissions
(Packet Mode Radio)
Back o counter
(Packet Mode Radio)
Packet expiration
time (Packet Mode
Radio)
NOTE! Only in QAM
modulation models!
FSK models
- Retransmissions for data and RTS in Point-to-point and
Repeater network topology modes.
- When enabled, RTS message is retransmitted max. 4 times,
data max. 2 times.
- Retransmission process executed aer the set max. Back O
Counter Value.
QAM models
- Retransmissions for data in the radio layer.
- When enabled, radio router executes the retransmissions
according to the adjusted time limit (see Packet expiration
time).
- Retransmissions done aer max. packet length if RTS/CTS/
ACK messages are not recognized from the radio network.
- Can be set dierently to radio routers in the radio network.
Denes the retransmission time for radio layer handshaking
messages in case the radio channel is occupied.
FSK models**): Shall be set equally to the radio network
devices.
- With Fast Mode –mode selection, raling done always if back-
o counter greater than 0
0 1.2040
QAM models
- Can be set dierently to radio routers in the radio network
- Modem decides when to freeze the BOC value. Priority
(transmission turn) raises higher in every lost transmission
turn (only remaining BOCV are taken into account in the next
rale time for the same data paket).
0 (ms)*. Recommended to be set to dier from the factory
value, e.g. 1000 (ms)
- Data retransmissions in the radio layer (if enabled) and
transmission request (RTS) max. sending period, if the radio
network is occupied.
- NOTE! The set time value is extended if the retransmitting
radio notices other transmissions in the radio network and is
forced to wait.
0 1.365
0 1.2003
*) Default setting
**) NOTE! The settings must be set equally to all radio modems in the same radio network.
RTS = request to send
CTS = clear to send
ACK = acknowledgement for the data packet
59
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7. Settings
3
Figure 7.11 Packet Mode Radio Access Control; FSK model by WEB user interface
Figure 7.12 Packet Mode Radio Access Control; QAM model by WEB user interface
60 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
7. Settings
3
Figure 7.13 Examples of the network topologies and corresponding settings with FSK model. Please contact SATEL
for further information regarding the recommended setting for the operational mode.
SA00065
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
Modem A
Modem A
Repeater
Modem C
Network topology: Repeater
Setting: Repeater
Network topology: Point-to-Point
Setting: Point-to-Point or Fast mode
Network topology: Master-Slave
Setting: Point-to-Point or Fast mode
Modem B
Modem B
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
TD
RD
PWR
STAT
RX
TX
CTS
RTS
USB
ETH
PWR
STAT
OK
Modem A
Modem B
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8. Accessories
3
8. Accessories
The RU is delivered with the following accessories:
– A DC connector
– Cable shield for the DC connector
– A user guide
The SATELLAR specic DIN rail adapter and wal mount parts can be ordered separately. If the RU is used
as a standalone device, it can be delivered with a plastic front cover.
SATEL oers a wide range of other accessories too, please contact SATEL or local SATEL distributor, in
order to have more information.
62 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
9. SATEL open source statements
3
9. SATEL open source statements
ALL OPEN SOURCE SOFTWARE used in this product is distributed WITHOUT ANY WARRANTY and is subject
to copyrights of one or more respective authors.
9.1 AES Encryption
This product includes cryptographic “Advanced Encryption Standard” soware.
AES implementation copyright (c) 1998-2008, Brian Gladman, Worcester, UK. All rights reserved.
License terms
The redistribution and use of this soware (with or without changes) is allowed without the payment of
fees or royalties provided that:
1. Source code distributions include the above copyright notice, this list of condi-
tions and the following disclaimer;
2. Binary distributions include the above copyright notice, this list of conditions
and the following disclaimer in their documentation;
3. The name of the copyright holder is not used to endorse products built using
this soware without specic written permission.
Disclaimer
This soware is provided ‘as is’ with no explicit or implied warranties in respect of its properties, including,
but not limited to, correctness and/or tness for purpose.
63
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10. Troubleshooting
3
10. Troubleshooting
10.1 Error codes
If the RU displays an error state, an error message is displayed for the user as a ve digit binary number.
The LED indicators will blink slowly, about once in a second, alternating between all indicators on and the
error code on condition. LSB (least signicant bit) is in PWR and MSB (most signicant bit) in CTS. In addi-
tion by the uppermost LED (RX) there is indicator which a processor will report the error. If the RX LED is o
the error originates from the master processor and if it is on the error report is from the signal processor.
The error codes are presented in the table below.
TD
RD
PWR
STAT
RX
TX
CTS
RTS
SA00041
PWR
STAT
RD
TD
CTS
RTS
TX
RX
OFF =error from master processor
ON =error from signal processor
LSB
(Least Significant Bit)
MSB
(Most Significant Bit)
Name Description Code LED Required action
ERROR_CAT_FPGA _
VERSION
FPGA is not compatible
with the rmware
version
0 0001
(1)
•
•
•
•
•
•
•
•
Switch to the previous rmware
version. If not possible the unit should
be sent to service.
64 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
10. Troubleshooting
3
Name Description Code LED Required action
ERROR_CAT_FPGA _
COMM
Error in FPGA MCU
communication
0 0010
(2)
•
•
•
•
•
•
•
•
Switch to the previous rmware
version. If not possible the unit should
be sent to service.
ERROR_CAT_BOARD_
VERSION
PWB version not
compatible with the
rmware version
0 0011
(3)
•
•
•
•
•
•
•
•
Switch to the previous rmware
version. If not possible the unit should
be sent to service.
ERROR_CAT_HW_INIT_
GENERAL
Problem in HW
initialization (other than
memory related)
0 0100
(4)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_VOLTAGE Internal voltage
monitoring has detected
out-of-limits values for
certain voltages
0 0101
(5)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_PA_
CURRENT_HIGH
RF power amplier
current has exceeded
the limit and the
transmitter has been
shut down to protect the
electronics
0 0110
(6)
•
•
•
•
•
•
•
•
a) Check the antenna impedance
match and if needed improve the
match.
b) Wait for a while and restart the data
transmission. If the problem remains
the unit should be sent to service.
ERROR_CAT_PA _TEMP_
HIGH
RF power amplier
temperature has
exceeded the limit and
the transmitter has been
shut down to protect the
electronics.
0 0111
(7)
•
•
•
•
•
•
•
•
a) Check the ambient temperature. It
might be too high.
b) Wait for a while and restart the data
transmission. If the problem remains
the unit should be sent to service.
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10. Troubleshooting
3
Name Description Code LED Required action
ERROR_CAT_PLL_LOCK The RF frequency
synthesizer has not
been locked and
either transmission or
reception is not possible.
0 1000
(8)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_RAM_
CHECK
RAM memory
verication failed during
initialization.
0 1001
(9)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_SW_
FAILURE_1
Watchdog originated
reboot because of a SW
crash
0 1010
(10)
•
•
•
•
•
•
•
•
No actions required. If the same
happens repeatedly the unit should be
sent to service.
ERROR_CAT_SW_
FAILURE_2
The SW has recognized
an error and gone into
error state
0 1011
(11)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_NVM_
COMM
No access to the non-
volatile memory
0 1100
(12)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_NVM_
UNINITIALIZED
Non-volatile memory
has entered an
unformatted state due to
an internal error.
0 1101
(13)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
66 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
10. Troubleshooting
3
Name Description Code LED Required action
ERROR_CAT_NVM_
SETTING
Illegal value in a user or
other setting.
0 1110
(14)
•
•
•
•
•
•
•
•
Go through the user settings to nd
any illegal value. If there is not any
reboot the unit. If the problem remains
the unit should be sent to service.
ERROR_CAT_NVM_
CORRUPT
Corrupted non-volatile
memory
0 1111
(15)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_INTER_
PROCESSOR_COMM
An internal
communication error
between MCU and DSP
processors
1 0000
(16)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_INTER_
SUBUNIT_COMM
Communication
problem between the
subunits, e.g. between
the Radio and Central
units.
1 0001
(17)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_
SUBSYSTEM_USB_HOST
An error in USB host
system
1 0010
(18)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains the unit should be sent to
service.
ERROR_CAT_
SUBSYSTEM_SERIAL_
PORT
An error in external serial
interface
1 0011
(19)
•
•
•
•
•
•
•
•
Reboot the unit. If the problem
remains make sure that the error is not
located on the DTE. If the error seems
to be in the RU it should be sent to
service.
Table 10.1 Error codes by LED indication
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10. Troubleshooting
3
10.2 Connection problems
There are some factors that may prevent proper connectivity. In generally it can be said that there are usu-
ally lots of instances in network – both hardware and soware – and they all have some eect to overall
performance.
One instance that may prevent traic is rewall. In example of TCP client SATELLAR tries to send TCP
messages to some target device. If this device has rewall conguration, which prevents messages from a
dened port, the sending of course fails. One good indicator of such case is the blinking sequence of the
radio unit LEDs. Normally when sending e.g. ping message the TX LED blinks rst for sending and then RX
LED for receiving and same goes basically for sending TCP messages.
Even the receiving end had no application listening to messages; the sending device should be able to
send messages to receiving end in proper way. If e.g. the conguration is as default - i.e. retry count is 5
and interval is 1000 milliseconds - LEDs in radio unit should blink 5 times with 1 second interval in such
case where no application receives them. This means that SATELLAR is able to communicate with TCP
stack of target device even though no application actually receives the messages. Other options are e.g. to
investigate the traic with Wireshark or to check the ports with netcat (nc).
But in case the LED blinking is not as systematic as described but instead more incoherent and the inter-
val tends to get longer, there may be an issue with target device rewall. In such case the target device
rewall conguration should be investigated.
As a summary couple of rules of thumb:
– Sending of messages to target must succeed even though there is no
application listening to them. This can be observed by e.g. LED blinking.
– Target device must have the dened ports opened in rewall for
communication.
– Ping is a good tool for diagnostics in network, but even though ping succeeds
between the devices, it does not ensure that all other communication is
available. There are dierent tools - such as netcat - that check the status of
dened ports.
68 SATEL OY // SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
11. Settings selection guide
3
11. Settings selection guide
11.1 Modem Settings
Menu Submenu Value (* = default)
Network
Protocol
Mode
NetID Satel NG * (max 8 characters)
Address (RMAC) 0001 * (1 - 4093)
Protocol Mode
- Basic-RX Priority - Basic-TX Priority
- B a s i c- R e p e at er - P a c k e t R o u t in g *
- S our ce Rou ting , ma ste r - So urce Ro uti ng , s lave
Network Size support 0=Small network (up to 150 modems)
1= Large network (up to 4000 modems)
Radio TX Frequency 460.000000 MHz (Depends on hardware conguration)
RX Frequency 460.000000 MHz (Depends on hardware conguration)
RF Output Power FSK-radio: 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2 and 5 W *
QAM-radio: 0.1, 0.2, 0.5, 1, 2 and 5 W * (Peak power values)
Signal Threshold FSK: -118 dBm. Adjustable in the range of -80 … -127 dBm
QAM: -110dBm. Adjustable in the range of -80 … -110 dBm
Over the-Air Encryption OFF * / ON
Forward Error Correction Trellis
Coding
OFF * / ON OFF * / ON
Channel Spacing FSK-radio: 12.5, 25 *, 150 kHz
QAM-radio: 6.25, 12.5, 25 * kHz
Air Speed / FSK-radio 12.5 kHz 25 kHz 150 kHz
4-FSK 9600 bps 19200 bps 115200 bps
8-FSK 14400 bps 28800 bps 172800 bps
16-FSK 19200 bps 38400 bps 230400 bps
Air Speed / QAM-radio 2-QAM 6.25 kHz 12.5 kHz 25 kHz
4680 bps 10080 bps 20160 bps
4-QAM 9360 bps 20160 bps 40320 bps
8-QAM 14040 bps 30240 bps 60480 bps
16-QAM 18720 bps 40320 bps 80640 bps
32-QAM 23400 bps 50400 bps 100800 bps
64-QAM 28080 bps 60480 bps 120960 bps
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11. Settings selection guide
3
Menu Submenu Value (* = default)
Serial
Connector
Conguration
Radio Unit Port
Assignment
NONE
DATA UART TO RADIO D9 RD/TD
DATA UART TO RADIO D9 RD/TD - NMS TO D9 DTR/DSR
DATA UART TO RADIO D9 RD/TD - NMS TO D9 RTS/CTS
DATA UART TO RADIO D9 RD/TD - NMS TO SATBUS
MCU UARTS TO SATBUS WITH CAN *
DTE Port Physical
Communication Mode
RS-232, RS-422, RS-485, FD-RS-485
Data Port
Settings 1)
Rate 9600 * (1200 - 460800) bps
Data Bits 7, 8 * bits
Parity No Parity Check *, Even, Odd
Stop Bits 1 *, 2 bits
Serial Data
Flow Control
TX Delay 0 * (0 - 65535)
CRC OFF / ON *
Handshaking CTS Line Clear To Send, TX buer state *, RSSI Treshold, Always ON
Handshaking RTS Line Ignored *, Flow control, Reception control
Handshaking CD Line RSSI treshold *, Data on channel, Always ON
Pause Length 3 bytes * (3 - 255)
Maximum Number of
Accepted Errors
0 * (0 - 255)
Packet Mode
Radio Access
Control
Network Topology / Handshake Point-to-point *, Repeater, Fast mode / ON, OFF
Retransmissions OFF / ON *
Back O Counter FSK: 8 * (suitable values 4 - 63)
Minimum Back O Counter Value QAM: 4 * (suitable values: 1 - 1023)
Packet Expiration Time 0 (ms)
NOTE! The Fast Mode selection is not available with 150 kHz channel.
1) See further details from section 5.1 Serial data, page 24
SATEL Oy
Meriniitynkatu 17, P.O.Box 142
FI-24101 Salo, Finland
Tel. +358 2 777 7800
info@satel.com
www.satel.com
MISSION-CRITICAL CONNECTIVITY
