ADTRAN TSU 120e - Manual (Page 93)

Chapter 7. Test Menu
61202129L1-1 TSU 120 User Manual 7-5
Remote Loopback can only be used with Fractional T1 if the ANSI
FT1 LLB is selected.
After a Remote Loopback option is selected, the TSU 120 veri-
fies that the far end is actually in a loopback by checking for the
receipt of a code looped back from the far end. Once the
Remote Loopback type is selected, the LCD displays the loop-
back progress by displaying
L OOPING
until loopback is verified.
Test Patterns
All Zeros
Sends an all zeros pattern to the network.
All Ones
Sends an all ones pattern to the network.
QRSS Pattern
The QRSS pattern is commonly used to simulate real data in T1
interfaces. This pattern can be assigned to appear in all DS0s or
only in TST DS0s. When QRSS is set in all DS0s and one of the
network loopbacks previously described is activated at the far
end, a total end-to-end integrity check can be run without the
need for any external test equipment. When QRSS is assigned
to TST DS0s, an integrity check of the link can be run along
with normal data flow. The TST DS0s are user-assigned as part
of the DS0 Map. This sets the pattern for the test and initiates
the transmission of the pattern. The test is terminated by select-
ing
N ONE
. The following patterns are available:
FT 1 LPBK Initiates the transmission of a FT1
loopback using the inband code
described in T1.403.
NO LOOPBACK Deactivates the loopback