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
18
3.5 Termination of RS-422/485 lines
Each differential pair of wires is a transmission line. A transmission line must be terminated
properly to prevent, or at least minimise, harmful reflections formed between the transmitting
and receiving end of the transmission line. A common method of terminating a RS-485 type of
transmission line is to connect a so-called termination resistor, between the wires and at both
ends of the transmission line. Even when there are more than two devices on the same
transmission line, the termination resistors are needed only at the ends of the transmission line.
The termination resistor must be selected so that its resistance matches the characteristic
impedance of the transmission line as close as possible (typical values range from 100 to 120
ohm). When using a RS-422 type of connection the termination resistor is connected only at
each of the receiving ends. Termination resistors are particularly important when using long
transmission lines and/or high data transfer speeds.