Avaya S8700 - Page 1884

Maintenance-Object Repair Procedures
555-233-143
8-1162 Issue 1 May 2002
Figure 8-67. ISDN-PRI Outgoing Test Call
Looped-back data
stream pattern is
generated by digital
port 1 and checked
by digital port 2 on
the TN771
Digital
Port 1
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TN771
Maintenance/Test
SPE
UN332
MSSNET
TN1655
PKT-INT
TDM
Bus
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Control
. . . . . .
Loop-back
Circuitry
Far-End
Equipment
B-channel carries
looped-back test signal
D-Channel instructs
far end to connect
loop-back circuitry
across B-channel
signal
External DS1 Facility
PBX Equipment
TN464
DS1
Interface
Packet
Bus
Digital
Port 2