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Remote Digital Loopback (RDL)
The Remote Digital Loopback (RDL) test checks the performance of both
the local and remote Model 1082s, and the communication link between
them. Any characters sent to the remote Model 1082 in this test mode
will be returned back to the originating device (see Figure 14, below). For
example, characters typed on the keyboard of the local terminal will
appear on the local terminal screen after having been passed to the
remote Model 1082 and looped back.
Figure 14. Remote Digital Loop
To perform an RDL test, follow these steps:
1. Activate RDL. This may be done in three ways:
— Move the front panel toggle switch down to
Remote
.
— Raise the RDL signal on the interface (see Appendix C, “Model
1082C and 1082D Interface Pin Assignments” on page 28).
Note Remote loopback cannot be activated until approximately 45
seconds after the two modems have linked to each other.
2. Perform a V.52 BER test as described in “Using the V.52 (BER) test
pattern generator” on page 24. If the BER test equipment indicates
a fault, and the Local Line Loopback test was successful for both
Model 1082s, you may have a problem with the twisted pair line
between the modems. You should then check the twisted pair line for
proper connections and continuity.
Note The Remote Digital Loopback (RDL) will not work for 144 kbps.
You must first set the units to 128 kbps or slower to use the RDL.
Important
Do not
send a 511 test pattern from the test equipment
when you connect external test equipment to the 1082.
RDL initiated
Remote 1082Local 1082