ADC SWD4573I1 Manuale Utente

The Avidia system supports loopbacks that enable you to test the data communication path 
between a card in the Avidia system and another device with the same transmission. You can 
run these loopbacks on DS1/DSX-1, DS3, and OC3 lines. The end-points for these tests are the 
near-end, which is the local Avidia card, and the far-end, which is the device (this could be 
another Avidia card) that is the remote end for the test.

When you initiate a loopback test on a data communication path, normal service is 
interrupted for that path until the test is cancelled. The system is then returned to normal 
operation.

The following table lists supported loopbacks.

See the following sections to initiate loopbacks for specific line card types:

Local

OC3
DS1
DS3

For this loopback, the signal is looped back within the line card at the 
transceiver.

Line

OC3
DS1/DSX-1
DS3

For this loopback, the signal is received at the line interface and is looped 
back through the transmitter. The near-end interface receives the 
loopback from the far-end device. You can activate this test either from 
the near-end or far-end.

A line loopback tests the complete signal for the port, including channels 
that are blocked by the user.

Payload

DS1/DSX-1

For this loopback, framing for the DS1/DSX-1 port must be set to ESF. 
The DS1/DSX-1 card loops the payload (192 bits) through the receive 
section (including the framer) and to the transmit section, returning the 
payload and the newly generated ESF framing.

Remote

DS1/DSX-1
DS3

For this loopback, the signal is sent to the far-end where it is looped 
back. This loopback tests the entire data path to the far-end.