Zhone Technologies Z-PLEX-10-24-DOC-SC Manuel D’Utilisation

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Zhone Technologies / 5-1
Diagnostics
T1 loopbacks
Chapter 5
Diagnostics
This chapter describes how to perform loopbacks on the Z-Plex unit interfaces. It also 
describes the system’s LEDs. It includes the following topics:
5.1
T1 loopbacks
The T1 interfaces support local and line (network) loopbacks:
During a line (network) loopback, the signal is looped back to the network. The receive 
T1 signal is looped onto the transmit T1within the framer chip.
During a local loopback, the signal is looped back to the user. The transmit T1 signal is 
looped onto the receive T1within the LIU. 
The Z-Plex unit supports ESF loopback detection sent from remote equipment. These codes 
are ANSI T1.403 compatible with DS1 networks and allow the unit to detect a latching 
loopback to remote DS1 equipment. The Z-Plex detects payload loopback (PLB), network 
loopback (NLB), and line loopback (LLB). The Z-Plex also supports TR 54016 for loop up 
and loop down cases.
Figure 5-1 on page 5-2 illustrates T1 loopbacks on the Z-Plex unit.