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6 To determine the current status of the loopback test, either 

locally-initiated or remotely-initiated, and to determine if the V.54 
loopback detection is on, enter:

This section describes how to perform a local loopback test using the 
loopback plug on the built-in 56/64 Kbps CSU/DSU on the model 45x and 
55x bridge/router.

Figure 11 shows the data flow that occurs when this loopback test is 
performed.

Figure 11   CSU/DSU Local Loopback Testing

Before running the CSU/DSU loopback test, attach a console or Telnet to 
your bridge/router.

To perform a local loopback test on the built-in CSU/DSU, follow 
these steps:

1 Uncable the WAN port and insert the loopback plug that came with your 

system.

2 Set the baud rate to 56 Kbps by entering:

3 Set the owner of the WAN port to loopback by entering:

4 Select the loopback test mode by entering:

CSU/DSU port

with loopback plug