User`s manual

Chapter 4 Monitoring and Maintenance
93
Figure 4-15 Loopback
The MUXpro series support Optical and E1 user-controlled loopback function.
Both Optical and E1 support local (analog) loopback and remote (digital) loopback.
The available test and loopback functions are described in the following
paragraphs. The front panel LED (TST) of MUXpro will be ON while the loopback
test is taking place.
Local Looback：
When the local loopback is activated on a selected port, it connects the port
transmitting signal to the input of the receive path. The test signal is provided by
the equipment, which is routed by the DXC data pump to that port. This equipment
must receive its own transmission.