ISDN Test Call Test (#258)

Last Updated : Sep 29, 2023 |

This test performs a far-end looparound test over an ISDN trunk if:

  • The trunk is in-service, maint-NE, or out-of-service/NE.

  • No calls are active on the trunk.

  • The system uses country protocol 1 (including US), or the far end has looparound capability.

The test sets up a call to a far-end switch over the trunk to be tested. If a Maintenance/Test media module does not reside in the system, the test call connection is established over the TDM Bus of the transmit and receive sides of the ISDN-PRI trunk to a data channel.

If a Maintenance/Test media module does reside in the system, the test call connection is established over the TDM Bus of the transmit and receive sides of the ISDN-PRI trunk to a digital trunk testing port on the Maintenance/Test media module. The digital port on a TN771D Maintenance/Test media module sends a bit pattern to the far end which is echoed back. If the received pattern matches the pattern that was sent, the test passes. If there are differences, the test fails.

If a test call is running when scheduled maintenance starts, the green LED is turned off. To determine whether a test call is still running:

  • Enter list isdnpri-testcall and status isdnpri-testcall.

  • Check for a lit amber LED on the Maintenance/Test media module.

Synchronous Test Calls

Enter one of the following commands to initiate a synchronous outgoing test call:

  • test trunk grp#/mem# long [repeat #]

  • test board location long [repeat #]

  • test port location long [repeat #]

The duration of the test call is 8.6 seconds for unrestricted (B8ZS) B-Channels and 9.4 seconds for restricted (ZCS) B-Channels. The test fails if the bit error rate retrieved from the Maintenance/Test digital port is greater than 0. When this occurs, perform further diagnostics such as test isdnpri-testcall.

Asynchronous Test Calls

You can start, query, and stop an outgoing test call by using the following commands:

  • test isdnpri-testcall grp#/mem# [minutes #]

    This command initiates an outgoing ISDN-PRI test call up to 120 minutes. Default times are as above. Only one trunk per PN can be tested at one time.

  • status isdnpri-testcall grp#/mem#

    This command displays the progress of the outgoing test call by reporting bit and block error rates of the tested B-Channel.

  • clear isdnpri-testcall grp#/mem#

    This command terminates an outgoing test call already in progress. Measurements already collected are not cleared until the next test call begins.

A PASS of the asynchronous test indicates only that the test call was successfully established. Enter status and list to get the results of the test.

Note:

Before attempting to make an ISDN-PRI test call to the public network (that is, the network of the far end), make sure that test call service is provisioned by the network. The user must subscribe to Test Type 108 service and have the correct far-end test call number administered on the trunk group form for the call to be allowed.

Only one trunk can be tested in a given port network, until the test call is canceled or completes.

This test is run on the following maintenance objects: