
Chapter 4 Maintenance IP6704A TDMoEthernet
Loop Telecommunication International, Inc.
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4.
MAINTENANCE
4.1.
Self-Test
When the Loop-IP6704A is powered up, a complete self-test routine is run to check all I/O
ports, read/write memory, and data paths to validate system integrity. During system
self-test, "TESTING" message and testing code are shown on the VT100 terminal screen.
If any error is found, a testing code will be showed on the VT100 terminal display. Various
system diagnostic methodologies can be found in the following paragraphs.
4.2.
Near End Loopback
The near end loopbacks such as digital local loopback and line loopback are activated by
the Loop-IP6704A. The loopbacks are at the near end facility. The following paragraph
describes each loopback in detail.
4.2.1.
E1/T1 Line Loopback
Line Loopback is illustrated in Figure 4-1. The incoming E1/T1 Line signal is loopback to
the E1/T1 Line before the Payload mapper. This Line Loopback is used to isolate the local
equipment from a problematic E1/T1 transmission line. Line loopback test can be
activated from the VT-100 terminal.
2
Line Loopback
Loopback to Ethernet
LIU
1
2
1
Line
Figure 4-1 Loopback Block Diagram