User's Manual
Table Of Contents
- IMPORTANT NOTICE
- RESTRICTIONS ON USE
- PRODUCT CONFORMITY
- WARRANTY AND SAFETY INSTRUCTIONS
- TABLE OF CONTENTS
- INTRODUCTION
- 1 TECHNICAL SPECIFICATIONS
- 2 OPERATING VOLTAGE
- 3 SERIAL INTERFACE
- 4 USER INTERFACE
- 5 RF INTERFACE
- 5.1 Transmitter
- 5.2 Receiver
- 5.3 Priority RX/TX
- 5.4 Error correction
- 5.5 Error checking
- 5.6 User data whitening
- 5.7 Pacific Crest and TRIMTALK compatibility
- 6 TRANSPARENT DATA TRANSMISSION
- 7 SETTINGS
- 8 SW-RELATED COMMANDS AND OPTIONS
- 9 ACCESSORIES
- 10 APPENDIX A
- 11 APPENDIX B
SATELLINE-M3-TR1
User Guide, Version 3.0
22
Error correction improves the reliability of data transfer via the radio interface especially in
unfavourable conditions. FEC-function should be used when link distances are long and/or if
there are many disturbances in the radio channels used. The use of the FEC-function will,
however decrease the data transfer throughput of data by about 30 %. For a listing of exact
delays introduced by using FEC-function.
To switch the FEC-function ON in the Programming Mode, select:
7) Additional Setup =>
Error correction => set ON/OFF
5.5 Error checking
When the error checking is switched on, the radio modem will add a checksum to the
transmitted data. When the data is received, the checksums are verified before data is forwarded
to the serial port. There are two different options for error checking that can be accessed in the
Additional setup menu in the Programming Mode:
7) Additional Setup =>
Error check => set ON/OFF, Full CRC16 check => set ON/OFF
Error check checks data partially while data is received.
Full CRC16 check function adds two checksum characters at the end of the user data message.
At the reception end the receiver receives first the whole package and if the checksum matches
the data message is forwarded to the serial port. If Full CRC16 check is selected it must be set
ON for all radio modems in the same network. Otherwise the checksum characters appear at
the end of user message on the serial port.
5.6 User data whitening
In some cases, if the user data includes a large number of constant characters, additional bit
errors may appear. The use of error correction (FEC) is recommended in such cases. If that is
not possible, the Data whitening feature can be used to improve the reliability of data transfer.
The feature is set on/off in the programming mode.
NOTE!
All radio modems, which are to communicate with each other, must have the same setting
for FEC (ON or OFF). If the transmitting radio modem and the receiving radio modem has
different settings, data will not be received correctly.
NOTE!
All radio modems, which are to communicate with each other, must have the same setting for
Data whitening (ON or OFF). If the transmitting radio modem and the receiving radio modem
has different settings, data will not be received correctly.