22
SHM-B ASYNC
Pins 4, 5, 6, 8, and 20 should all be HIGH to enable
communication.
5. If pin 8 (Carrier Detect) is low, this indicates:
• a defective transmission line or connection
• a defective remote SHM-B
• 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 word structure and speed settings on your
