Patton electronic 2073 Operating Remote Digital Loopback RDL, BIT Error Rate V.52 Diagnostics

5.3.2 Operating Remote Digital Loopback (RDL)

The Remote Digital Loopback (RDL) test checks the performance of both the local and remote Model 2073s, as well as the communica- tion link between them. Any characters sent to the remote Model 2073 in the test mode will be returned back to the originating device (i.e, characters typed on the keyboard of the local terminal will appear on the local terminal screen after having been passed to the remote Model 2073 and looped back). See figure 7 below.

Figure 7. Remote Digital Loop

To perform an RDL test, follow these steps:

1.Activate the RDL by moving the front panel toggle switch DOWN to remote.

2.Perform a bit error test (BERT) using the internal V.52 gener ator (as described in Section 5.4), or using a seperate BER Tester. If the BER test indicates a fault, and the Local Line Loopback test was successful for both Model 2073s, 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.

5.3.3BIT Error Rate (V.52) Diagnostics

The Model 2073 offers a V.52 Bit Error Rate (BER) 511 test pat- tern. This test pattern may be invoked along with the LAL and RDL tests to evaluate the unit(s) and the communication links.

When a 511 test is invoked, the 2073 generates a pseudo-random pattern of 511 bits using a mathematical polynomial. The receiving Model 2073 then decodes the received bits using the same polynomi- al. If the received bits match the agreed upon pseudo-random pattern, then the 2073(s) and the communication link(s) are functioning proper- ly.

511Initiates a built-in 511 bit pseudo-random pattern generator and detector.

511 with Errors Initiates a built-in 511 bit pseudo-random pattern generator and detector. The test pattern generator also injects intentional errors approximately once per second, causing the Error LED to blink.

To perform a V.52 BER test, follow these steps:

1.Locate the toggle switch group on the right side on the front panel and place it in the middle where it is marked “Normal”. This acti vates the V.52 transmission and reception of the selected test pattern. If there are errors in the received patt ern, the error LED will blink accordingly.

2.If the above test indicates no errors are present, move the

toggle switch UP to 511/E, activating the BER test

with intentional errors. If the test light is working properly, the local modem’s red error LED will blink approximately once per second.

NOTE: The above V.52 BER tests can be used independently of the Remote Digital Loopback tests. This requires two opera- tors: (1) to initiate and monitor the tests at the local Model 2073, and (2) to do the same at the remote Model 2073. In this case, the test pattern sent by each Model 2073 will not be looped back, but will be transmitted down the line to the other Model 2073. While one operator initiates test, the other monitors for errors.

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