Interface circuit pack or DS1 Interface Media Module on which it resides. This test will fail if there are problems with the ISDN-PRI Secondary D-channel port or the UDS1 circuit pack or the DS1 Media Module. This test will abort if a Secondary D-channel is not administered for the signaling group. If there are problems with the ISDN-PRI Secondary Signaling Channel port (ISDN-PLK), also investigate the MG-DS1 (DS1 Interface Media Module).

This test runs on ISDN-SGR (ISDN-PRI Signaling Group).