21
SHM-B PLUS ASYNC
• remote SHM-B without power
SYMPTOM:
TD and RD LEDs indicate data activity, but
data communication doesn’t exist.
1. Check the wiring of the EIA-232 port. Refer to
Section
3.2
for information.
2. Check the setting of S1. Refer to
Section 3.3
for
information.
SYMPTOM:
Transmitted and/or received data is full of
errors (garbled data).
1. Check for reversal of polarity on the four-wire
connection. Refer to
Section 3.1
and Figure 2.
2. Check communication settings (baud rate, parity,
word size) on your computing equipment for
consistency.
3. Wire the SHM-B units back-to-back, eliminating the
twisted-pair; see if you still have errors.
• If you do have errors, then test each SHM
individually in the following way: loopback one
SHM’s Transmit-to-Receive by using two short
