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SHM-B PARALLEL-T, SHM-B PARALLEL -R
4. Troubleshooting
Before installing the SHM-B Parallel, verify that the source of the parallel data
works correctly with the destination equipment when no modem link is installed.
This isn’t always possible, but be certain that all equipment is plugged-in and
powered on, and that all cables are securely connected. The most likely problems
and their causes are discussed below.
No data transfer
1. Incorrect wiring on the 4-wire circuit. See Figures 3-1 through 3-3. When the
lines are properly connected, both the TD and the RD LED on the units will
light Green in the idle state.
2. Incorrect baud rate, parity, or word length settings.
3. Distance/baud rate recommendations exceeded. Refer to
Chapter 1
to
determine recommended loop distance and baud rates.
4. Printer is off-line (Busy LED is lit red).
Garbled data (all data erroneous)
1. Incorrect wiring on the 4-wire circuit (wrong polarity).
2. Incorrect baud rate, parity, or word length settings.
Occasional data errors
1. Distance/baud rate capacity exceeded.
2. Poor quality loop (4-wire circuit); try different circuit or wire, try lower baud rate.
3. Excessive signal noise or crosstalk on the loop.
4. Marginal AC power source; check transformer output.
Busy LED stays on
1. Printer off-line or not operational.
2. Incorrect wiring on the 4-wire circuit (wrong polarity).