ADTRAN MX2800 M13 - Manual (Page 112)

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Section 6, Loopbacks MX2800 M13 Multiplexer User Manual
NOTE
Only one T1 port may engage a CSU Loopback, CSU Loopback w/BERT,
or a Line BERT. If a CSU Loopback, CSU Loopback w/BERT, or a Line
BERT is already active at the time a new CSU Loopback, CSU Loopback
w/BERT, or Line BERT is selected, the former test is terminated, and the
latter test is engaged.
3. DS3 LOOPBACKS
After DS3 Loopback is selected, the menu in Figure 6-8 appears. The sections following the figure
provide descriptions and illustrations of the testing options. Select Data Mode to end a test in progress.
Figure 6-8. DS3 Loopback Menu
CAUTION
If IP forwarding is enabled, a user should not perform a DS3 Loopback
from the menus of the far-end (non-LAN end) MX2800. The communi-
cation link is over the DS3. If a loopback is performed, communication
will be lost with the far-end MX2800. If this happens and a loopback
timeout is not active, the user must cycle power to the far-end MX2800 to
cancel the loopback and regain access to the shelf.