User Guide

T1
Loop Back Testing
8-20 Strata CTX I&M 06/04
Network/CSU T1 Span Test
This test verifies that the far end (CSU, Network, or CPE) T1 equipment and span cabling is
functioning properly. This test checks all T1 span cabling including the RDTU Amphenol cable
and connector. Guidelines for this test are provided in Figure 8-11.
Figure 8-11 Network/CSU T1 Span Test
Network/CSU/RDTU Span Test
This test checks all equipment that is checked with the test in the above paragraph, but this test
also checks that the RDTU Mitel LSI chip is functioning. Examples for this test are shown in
Figures 8-10~8-12.
Note Loop back tests with CSU and Network equipment can also be performed when connecting
the RDTU PCB directly to a customer premise (PBX, Key Hybrid, Channel bank) T1
circuit.
The RDTU Self Test is an active test of the RDTU circuit.
The Network/CSU Test checks all cables, the Network and CSU equipment (RDTU is not active).
The Remote Loop Back (RLB) Test is an Active test of RDTU (LSI MM8976B or DS2155), CSU,
Network equipment and all cables.
Network/CSU Check
Loop
Back
P1
Network
Interface
Unit
CSU
NDTU Cable
P2
On
On
P26, TT
P1, TR
P27, RT
P2, RR
Network
1672
Notes
● P1 and P2 to On position (see Figure 8-7).
● Unplug RDTU from Strata CTX back plane.
● CSU or Network T1 equipment should receive its own transmitted signal.
● Indications and results depend on CSU and/or Network equipment.
● Do not use the RDTU3A as a clock extraction unit.