Filter
Top Products
T1
T1
Loop Back Testing
Strata CTX I&M 06/04 8-21
Refer to Figure 8-3 and the CSU manufacturer’s Installation and Maintenance manual for
information on CSU Local/Network Loopback Tests.
Figure 8-12 Network/CSU/RDTU Span Test
Notes
● Local loop back and network loop back test cannot be performed simultaneously.
● CSU local/network loop back is a function of the CSU, not all CSUs provide this function –
see CSU I&M documentation for CSU loop back test procedures.
Test RDTU Lines
³ After loop back testing is complete and synchronized with the far end T1 circuit, perform test
calls on all RDTU lines.
RDTU
RDTU TX Open
MITEL Chip
P4
MM8976B
P1/P26 Transmit
P2/P27 Receive
NDTU Cable
RDTU Amphenol Pin Nos.
Network
CSU
Network
Interface
Unit (NIU)
2581
Top LED
Bottom LED
T = About 1/2 Second
Continue to Cycle when
P4 is in ON Position
0
0
0
0
0
ON Steady
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
Busy
FALM
FMALM
YALM
BALM
T1 T2 T3 T4 T5
0
0
ON or OFF, Steady
ON or OFF, Steady
Primary SYNC
Secondary SYNC
LEDS ON RDTU PCB
T6
1673