Bell 5902 - Page 4

5902 Bell 202 Modem Hardware Manual
October 19, 2007
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5.2 Half Duplex .................................................................................................. 23
5.2.1 Timing Diagrams ..................................................................................... 23
5.3 Sample Configurations ................................................................................. 26
5.3.1 Full Duplex Back-to-Back Modems ......................................................... 26
5.3.2 Full Duplex Constant Carrier Master ....................................................... 26
5.3.3 Half Duplex Slave for Constant Carrier Master ....................................... 27
5.3.4 Half Duplex Master Or Slave .................................................................. 28
5.3.5 High Speed Connection to TeleSAFE RTU ............................................ 28
5.3.6 Normal Speed Connection to TeleSAFE RTU ........................................ 29
5.4 System Configuration Procedures ............................................................... 30
5.4.1 Full Duplex Point-to-Point Systems ........................................................ 31
5.4.2 Half Duplex Multi-Point Systems ............................................................ 31
5.5 Common Problems and Solutions ............................................................... 33
5.5.1 RTS Always On in Half Duplex ............................................................... 33
5.5.2 High Error Rate ....................................................................................... 33
5.5.3 Modem Receives Data but Never Transmits .......................................... 34
5.5.4 Other Modems Do Not Receive Data ..................................................... 34
5.5.5 Bad Data at Start of Message................................................................. 34
5.5.6 Bad Data after End of Message ............................................................. 34
5.5.7 Missing End of Long Message ................................................................ 35
5.5.8 RS LED Always On; All Other LEDs Off. ................................................ 35
5.5.9 DTE Transmits Too Soon after Receive ................................................. 35
5.5.10 CD LED Always On in Master Modem .................................................... 35
5.5.11 CD LED Always On in Radio System ..................................................... 36
5.5.12 CD LED Always On in 2 Wire System .................................................... 36
5.6 LED Indicators ............................................................................................. 36
5.7 F Option ....................................................................................................... 37
5.7.1 Supported Communication Parameters .................................................. 37
5.8 M Option ...................................................................................................... 38
5.8.1 Carrier Turn Off and the Modbus RTU Protocol ..................................... 38
5.8.2 M Option Operation ................................................................................ 38
6 MAINTENANCE ........................................................................................... 40
6.1 Gain Adjustments ......................................................................................... 40
6.1.1 Transmitter Adjustment .......................................................................... 40
6.1.2 Receiver Adjustment ............................................................................... 40
6.2 Modem Test Modes ..................................................................................... 40