Verilink DIU 2130 (880-503297-001) Product Manual - Manual (Page 76)

56K NMS Option Overview
6-16 Verilink
This field selects which loop code to send in the channelized
data to the remote end when the RL lead on the DTE
connector interface module is forced high. Various loop
code types include:
V.54 Most useful in DDS mode
FT1 Used for fractional T1
Verilink Not useful in DDS mode
AM2000
Loopback
Activity Menu
Figure 5 is a AM2000 screen display of the loopback selections
available in AM2000.
Figure 5
AM2000 Display of the Select DIU 2130/DDS Loopback Activity
There are sub-menus for DDS latching loopback menu selections.
DDS Latching
Loopbacks
Once this loopback is started, it remains in effect until released by
another specific code sequence. This eliminates most restrictions
on the test data that can be transmitted.
NOTE: The DIU 2130 must be optioned for the 56K NMS Option for
latching loopbacks to work.
When you select the DDS latching loopback, the screen in Figure 6
appears. The possible choices are: