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This section describes how to perform a local line or payload loopback 
test using the loopback plug on the T1/FT1port on the model 46x and 
56x bridge/router.

Figure 13 shows the data flow that occurs when this loopback test is 
performed.

Figure 13   T1/FT1 Local Loopback Testing

Before running the T1/FT1 loopback test, attach a console or Telnet to 
your bridge/router.

To perform a local loopback test on the T1/FT1, follow these steps:

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

system.

2 Disable the WAN path by entering:

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

4 Start the loopback test by entering:

(for a line loopback test)

or

(for a payload loopback test)

If the number of received packets equals or approximately equals the 
number of transmitted packets, your line has passed the loopback test. If 
your line does not pass the test, verify that the software is configured 
correctly. Stop the loopback test by entering:

(for a line loopback test)

or

(for a payload loopback test)

T1/FT1 port

with loopback plug