User guide

Diagnostics 5-9
5
The Loopup/Down Remote Tests
The loopup remote test puts the remote DSU/CSU into network loopback.
Once in loopup remote, test patterns can be sent to verify the Bit Error Rate
(BER) performance of the bidirectional E1 network signal (Figure 5-5).
To put the remote DSU/CSU into network loopback, the local DSU/CSU
momentarily transmits the loopup code to the remote DSU/CSU. If the
remote DSU/CSU does not go into network loopback within 15 seconds, a
failure is declared and the DSU/CSU stops sending the loopup code.
The loop code and network parameters for the local and remote
DSU/CSUs must match. Use the loopdown remote test to terminate the
remote loopback.
To run this test from the front panel, refer to ÒLoopup Remote and
Loopdown RemoteÓ on page 5-13.
Figure 5-5 Loopup Remote Test
NOTE: To run multiple fractional loop payload tests, you must first
terminate any current tests (other than a fractional payload test).
NOTE: The full bandwidth loopup code puts the remote DSU/CSU in a
full bandwidth network loopback. The fractional loopup code puts the
DSU/CSU in a fractional (per individual port) payload loopback.
CSU
Local Solo E1
GR620
DTE
Network
Interface
Network
Interface
CSUDSU
DSU
Remote Solo E1
Data
Port
Data
Port