mit output will be connected to its own receiver. The TM LED will light
up.
2. Perform a BER (Bit Error Rate) test on each unit using a separate
BER tester. If the BER test equipment indicates no faults but the data
indicates a fault, follow the manufacturer's checkout procedures for the
data terminal. Also check the interface cable between the terminal and
the Model 1193RC. The BER test can also be performed using a built-
in 511/511E pattern generator. (See section 5.2.3 on how to use the
built-in 511/511E pattern generator.)
3. Upon completion of the LAL test, return the front panel switch to
NORMAL position. The TM LED should turn off.
5.2.2. Remote Digital Loopback (RDL)
The Remote Digital Loopback test checks the performance of both
the local and remote Models 1193RC, and the communication link
between them. In this test, any characters sent from the originating
device to the remote unit will be returned (see figure 12). Any data
sent to the remote unit from the remote DTE wil be ignored.
To perform a RDL test, follow these steps:
1. Activate RDL by moving front panel toggle switch LEFT to
"Remote". The TM LED on both local and remote units will light up.
2. Perform a BER (Bit Error Rate) test on the system, using BER tester
on the local end. BER test can also be performed using built-in
511/511E pattern generator. (See section 5.2.3 on how to use the built-
in 511/511E pattern generator.)
3. If the BER test equipment indicates a fault and the Local Analog
Loopback test was successful for both Model 1193RCs, there may be
a problem with the line between the units.
4. Upon completion of the RDL test, return the front panel switch to
NORMAL position. The TM LED should turn off on both local and
remote units.
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5.2.3. The V.52 Test Pattern Generator
To use the V.52 BER test in conjunction with the Local or Remote
Loopbacks, follow these instructions:
1. Locate the "511/511E" toggle switch on the front panel of the Model
1193RC and move it RIGHT. This activates the V.52 BER test mode
and transmits a "511" test pattern into the loop. If any errors are pres-
ent, the local modem's red "ER" LED will blink intermittently.
2. If the above test indicates no errors, move the V.52 toggle switch
LEFT, activating the "511/E" test with errors present. If the test is work-
ing properly, the local modem's red "ER" LED will blink approximately
once every 2 seconds. A succesful "511/E" test will confirm that the
link is in place, and that the Model 1193RC’s built-in "511" generator
and detector are working properly.
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Figure 12. Remote loopback diagram.
G.703/G.704
Network
Note: When set for Network Clock Mode, the unit will derive its timing
from the G.703/G.704 interface. It expects its clock will come from the
G.703/G.704 interface. Failure to connect to the G.703/G.704 may
result in bit errors during a 511 or 511/E test.
