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CHAPTER 6: Troubleshooting
6. Troubleshooting
Symptom:
TD and RD LEDs indicate activity, but units will not communicate
or data is garbled.
Problem 1:
Improper RS-232 wiring.
Solution 1:
Check wiring between the Modem and connected serial device—it
should be straight through.
Problem 2:
Improper twisted-pair wiring.
Solution 2:
Compare your twisted-pair wiring with the diagram in
Chapter 4
.
Problem 3:
Improper bit-rate setting.
Solution 3:
Make sure the bit rates on all connected serial devices are the
same.
Symptom:
TD and RD LEDs indicate activity, but CD LED is unlit or red
(should be green).
Problem 1:
Defective twisted-pair line.
Solution 1:
Test continuity of the twisted-pair line.
Problem 2:
Poor twisted-pair connections to Modems.
Solution 2:
Check screw terminal/RJ-11 connections to Modems; check
integrity of plug RJ-11 terminations.
Symptom:
Occasional data errors.
Problem 1:
Distance/bit-rate capacity exceeded.
Solution 1:
Check specifications in
Appendix A
.
Problem 2:
Poor-quality twisted-pair circuit.
Solution 2:
Use a different twisted-pair circuit if available.
Problem 3:
Poor twisted-pair connections to Modems.
Solution 3:
Check screw-terminal/RJ-11 connections to Modems; check
integrity of plug RJ-11 terminations.
