
Operating the DSU
When a DBM (control or tributary) originates Remote Digital Loopback, both the originating DBM and the targeted DBM enter Test mode. No other test can be run at the originating DSU or the targeted DSU until the Remote Digital Loopback is aborted.
The DBM does not generate test results.
NOTE
To activate a V.54 Loopback from the NMS to a DSU, first enable V.54 Lpbk (DSU option set) at both the control and tributary DSUs. Then, select
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Bilateral Loopback
Bilateral Loopback (Bilat Lpbk) is a combination of DTE and Digital Loopbacks operating simultaneously in the same DSU. Both Bilateral and Digital Loopbacks are selected from the DSUpt (DSU Port) or DBMpt (DBM Port) option set.
NOTE
If Bilat Lpbk is enabled, requesting a Remote Digital Loopback or Digital Test will automatically initiate a DTE Loopback, as well.
Digital Test
Only available to a DBM, the Digital Test (DT) checks the functionality of a pair of DBMs. This test is run on the DBM over the backup connection to a remote DBM for
The remote DBM is placed in Digital Loopback, then the local DBM transmits the
During the test, the TXD, RXD, and RTS LED indicators show the states of the leads at the DTE interface if the DBM port leads are being displayed. At the conclusion of the test, the local DSU releases the remote DBM from Digital Loopback.
To review the results of the test, select Displ (Display)
and press the key to scroll through the results shown in Table
When the test is over, the top line displays Final instead of Active.
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| Table |
| Digital Test Results | |
Results |
| Information Displayed |
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Time: |
| Running test timer. (The Clr |
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| selection resets the timer to |
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| 0:00:00.) |
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Tot Error: |
| Running count of bits in error; |
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| Max, if the maximum error |
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| count has been reached, the |
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| maximum being 64000. (The |
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| Clr selection resets the counter |
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| to 0.) |
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Err Secs: |
| Running count of errored |
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| seconds. (The Clr selection |
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| resets the counter to 0.) |
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End-to-End Test
Only available to the DBM, the
To view the results of the test, select Displ (Display)
and press the key to scroll through the results shown in Table
When the test is over, the top line displays Final instead of Active.
December 1996 |