Avaya 03-300430 User Manual

The Maintenance/Test digital port is a port on the TN771D circuit pack. Ports 2 and 3 are digital 
ports. The Maintenance/Test digital port provides the ability to perform digital (i.e., ISDN-PRI) 
trunk testing via the TDM bus. For an ISDN-PRI test call, connections are set up in the system 
as shown in 

When the Maintenance/Test digital port is participating in an ISDN-PRI test call, the port sends a 
stream of pseudo-random data along the connected B channel. The far end loops back this 
data, and the Maintenance/Test digital port compares the data to that which was sent. Errors are 
recorded on a bit and block basis. Refer to ISDN-TRK (DS1 ISDN Trunk) Maintenance 
documentation for more information about ISDN-PRI test calls.
The Maintenance/Test digital port maintenance ensures that the digital trunk testing function is 
operating correctly. The Maintenance/Test digital port is alarmed if maintenance determines that 
the digital port is operating incorrectly.

Note:

An alarm on the Maintenance/Test digital port reduces service, but does not block 
it since the ISDN-TRK has other means to determine the health of the ISDN-PRI 
trunk facility. However, to accurately measure the error performance and to 
ensure accuracy of the health of the ISDN-PRI trunk, the Maintenance/Test circuit 
pack should be replaced when a new circuit pack is available.

M/T-DIG

MIN

test port location l 

Maintenance/Test digital port

M/T-DIG

WRN

release port location 

Maintenance/Test digital port