25
SHM-768K
Table 4-1. Control Functions. (The item labels in this table
correspond to Figure 4-1.)
Item
Control
Function
A
DIG
The Digital loopback switch causes the local
SHM-768K to loop received data and clock to
its transmitter. Data Set Ready goes low (Figure
5-5).
B
ANA
The Analog loopback (V.54 loop 3) switch
causes the local SHM-768K to loop its
transmitter output back to its receiver (Figure
5-3). This loopback may also be activated from
the DTE when “DTE COMMAND ALB” strap is
set to EN.
C
REM
The Remote Digital Loopback (V.54 Loop 2)
switch causes the remote SHM-768K to loop
received data and clock to its transmitter (Figure
5-4). Data Set Ready goes low. This loopback
may also be activated from the terminal when
“DTE COMMAND RLB” strap is set to RLB EN.
D
PATT
The PATT switch causes the SHM-768K to send
and receive a 511 test pattern. If errors are
encountered, the ERROR LED is ON or blinks.
Receive Data and Clear to Send go low.
NOTE: Jumper “CARRIER” should be set to
“ON;” if the jumper is set to “CNTRL,” the RTS
signal must be high.
