Motorola UTA220, User Manual

Page: 124 / 187

14-4
UTA220/UTA220k
Diagnostics
Figure 14-4. Digital Loopback Test
To initiate the test, select the DIGITAL LOOPBACK option
from the PORT TEST submenu. The UTA220 must be on-line
when the test is initiated (a call must be placed) before the unit
can loop B-channel data. Any protocol, mode, and DTE rate
may be used, although the protocol and DTE rates on the two
units must be compatible. The remote unit should be set to the
same rate adaptation protocol as the local UTA220, and left in
normal data mode (NOT placed in Bilateral test mode). Data
sent by the remote UTA220 will be received by the local
UTA220, then echoed back to the remote UTA220. The test is
successful if the data is correctly echoed back to the sender. A
BERT device can be helpful in checking for data errors.
The test should be run in both directions if possible (i.e. use
the local UTA220 as both the sending unit and as the loopback
unit). If the B-channel data test is successful, it indicates that
the local and remote units and network are functioning. If there
are errors, the problem could be in any of those elements.