Latching Loopback (9623, 9626); Send 511 (9623, 9626) - Paradyne iMarc SLV Operation Manual

5. Troubleshooting

Latching Loopback (9623, 9626)

A latching loopback is a network-initiated DSU Loopback. Once a DSU Loopback
is started, the iMarc unit remains in loopback until it receives the loopback-release
sequence from the network.
The latching loopback code is a control sequence (as opposed to a bipolar
violation sequence); therefore, user data may cause the iMarc unit to activate the
loopback.
Disable the DSU Latching Loopback configuration option to stop the latching
loopback when the network did not command the test.

Send 511 (9623, 9626)

This test sends the 511 test pattern over the selected interface. The 511 test
pattern is a pseudo-random bit sequence (PRBS) that is 511 bits long (on the data
ports only). This is a PRBS 2
When sending or monitoring a 511 test pattern using an external loopback
connector on the network or DTE port, you must follow the sequence below for
these tests to run correctly.
Procedure
To send a 511 test pattern using an external loopback connector:
5-44
Main Menu→Configuration→Network→Physical
Main Menu→Test→[Network Physical Tests/Data Port Physical Tests]→
Send 511
1. Remove the network cable so that a No Signal (NS) condition occurs.
2. Start the Send Pattern test.
3. Place the loopback cable on the network or DTE port interface.
4. Start the Monitor 511 test.
May 2003
9
–1 test.
9000-A2-GB33-20