User guide

Diagnostics and Troubleshooting 6-9
6
It loops the data received from the T1 network back to the network. The data is
regenerated before it is looped back, however, the DSU/CSU does not perform
additional processing of the data.
This minimizes the impact of the DSU/CSU during the test so that network problems
can be isolated.
Figure 6-3 Loop NET Test
The Loop Payload Test
The Loop Payload test veriÞes proper operation of the DSU/CSU and the T1 network.
It loops the payload data received from the T1 network back toward the network.
Before it is looped back, the data is regenerated and a new framing pattern is inserted.
Thus, the proper T1 framing of the DSU/CSU and network can be veriÞed.
DTE
S
DSU
CSU
Data
Ports
CSU
Network
Interface
DSU
Data
Ports
Data
Ports
Network
Interface
Local
multi-port DSU/CSU
Remote DSU/CSU
DTE
DTE
DTE
DTE
DTE
AUX
Port
PBX