Tests
DS0 Tests
4-20
SpectraComm 553 Fractional T1 DSU
076R155-000
Installation and Operation Manual
Issue 7
Figure 4-22
DS0 Circuit Delay Test
DS0 Loopback
A DS0 Loopback commands the DSU to loop one, selected DS0 back to the remote. The remote
site is responsible for test pattern generation and checking.
A DS0 Loopback can be initiated from the terminal interface or by SNMP control.
Figure 4-23
DS0 Loopback
SC 553 DSU
Remote DSU
DTE
Inter-
face
TPG
TPC
Framer
TX
Driver
Analog
Receiver
Network
Analog
Receiver
TX
Driver
Framer
DTE
Inter-
face
TPG = Test Pattern Generator
TPC = Test Pattern Checker
Local DSU transmits and monitors test pattern on
the selected DS0, and measures time required
for the round trip.
SC 553 DSU
DTE
Inter-
face
Framer
TX
Driver
Analog
Receiver
Network
Only the selected DS0 is looped