Northern UTA220/UTA220k - Manual (Page 121)

UTA220/UTA220k
14-1
Diagnostics
Chapter 14
Diagnostics
COMMUNICATION DIAGNOSTICS
Communication diagnostic tests verify that the UTA220, the
DTE, the NT1, the central office switch, and the remote unit
are operating correctly. These tests can help determine the
source of a fault down to a particular element responsible for it.
GLOBAL TESTS
Communication tests are initiated and terminated via the front
panel under the GLOBAL TEST submenu of the
DIAGNOSTIC OPTIONS menu. The following sections
describe each of the diagnostic tests, when to use them, and
what it means if they fail.
2B+D Loopback
This test sets the UTA220 up for a data integrity test that is run
from the central office switch (Figure 14-1). This test causes
the unit to loop data received from the ISDN on the D-channel
and each B-channel back to the ISDN.
Figure 14-1. 2B+D Terminal Loopback Test
This is not a complete loopback; it is an echoing loopback
where the D-channel loopback point is different from the
B-channel loopback points.