The Layer 2 Status Query Test checks the Layer 2 status of the ATM-SGRP or ISDN-PRI Signaling Channel (D-channel). This test will fail if there is a hardware failure or a facility problem, or if the primary and secondary ISDN-PRI D-channels are not administered correctly.

The Primary and Secondary Signaling Link Hardware Tests (Tests #636 and #639), the ATM Remote Layer 3 Query Test (test #1291), and the Remote Layer 3 Query Test (#637) will detect most problems caused by hardware failures or incorrect administration.

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