18
HIGH SPEED SHM-B ASYNC AND CARD
also, Transmit - (TX-) must be wired to Receive
- (RX-). Refer to Figure 2 during your
inspection of the four-wire circuit.
3. Try a local test using the Loopback mode (see
Chapter 4
). If there is no transfer, check the
wiring of your EIA-232 cable and the setting
for jumper W1 (DTE/DCE select).
4. The EIA-232 control signals may be at the
wrong levels. If jumper W2 is in the A-B
position, try moving it to the B-C position to
internally enable the driver circuit on the High
Speed SHM-B Async unit. If data transfer now
occurs, either an EIA-232 control signal
supplied to the High Speed SHM-B Async by
the attached RS-232 device was not at the
correct level, or jumper W2 was improperly set
for your application. Refer to
Section 3.4
to
determine which flow-control leads are needed
to support your application.
5. If pin 8, Carrier Detect (with jumper W1 in
the XW1B position), or pin 20, Data Terminal
Ready (with jumper W1 in the XW1A position),
is low, this indicates:
• a defective transmission line or connection
• a defective High Speed SHM-B Async
• a High Speed SHM-B Async without power
