Loop Telecom IP6610, Руководство пользователя

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Chapter 3 Operation
17
3.16 Verifying Loop-IP 6610 Operations
The purpose of this section is not to help the user determine where a possible fault in the network may lie.
For this, the user needs to know the exact geometry of the network. Then standard network trouble shooting
procedures should be followed, which involve sectionalizing the network and performing loopback tests on
pieces of the network.
The purpose here is to help the user determine whether the Loop-IP 6610 equipment is at fault after tests
have pointed a suspicious finger at this equipment. The procedures outlined here depend on test equipment
and other equipment the user may have on hand.
The organization of these procedures starts from the simple to the complex. The procedure ends when a
definitive conclusion is made that the Loop-IP 6610 equipment is at fault. To verify that the Loop-IP 6610
equipment is not at fault, specialized equipment such as a BERT (bit error rate test) set is needed.
3.16.1 Independent Test
Remove all line and connections to the Loop-IP 6610. Remove power. After a few seconds, re-apply power.
Observe the power-up self-test sequence. If this fails, then Loop-IP 6610 has failed. See if the LEDs show
any abnormal displays. If yes, use the LED indications to guide the user to test other parts of the network,
such as the E1 line.
Especially during initial installation, excessive errors may be due to (a) incorrect configuration of either
Loop-IP 6610 or of the equipment at the other end of the line, or (b) due to faulty line installation, which
results in excessive noise, cross talk, or impedance mismatch. Especially in electrically noisy environments,
such as central offices, use of shielded cables is mandatory.
3.16.2 Substitution
If a spare Loop-IP 6610 plug-in is available, then replace the working one with the spare. The user must
carefully configure the spare exactly as the working one. If the substitution clears the problem, then the
original working one is suspect. Note that this is not definitive as other reasons may cause the same
symptom. A good practice is to reconfigure the original one and swap once more.
If both units behave the same, then the problem is probably elsewhere.
3.16.3 Using Loopback Plugs
Without a spare, loopback plugs are handy for diagnosis. Note that internal loopback facilities of the Loop-IP
6610 do not include the interface circuitry. Thus a plug is needed for each interface to complete the tests.
These plugs are wired such that signals from the Loop-IP 6610 are loopback by hard wire back to the
receive pin of the same plug.
Replace the line connector with a loopback plug. Observe if the line is in sync. If not then Loop-IP 6610 has
failed. Then perform a PRBS test towards the line. If this fails, then Loop-IP 6610 has failed.
Note that if a far end terminal is available, the first test should be a local line loopback to see if the line is
good.
If tests with loopback plugs all pass, then the problem is probably elsewhere.