Avaya Media Gateway G250, Руководство администратора

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Issue 5 June 2008 351
Chapter 12: Configuring Emergency
Transfer Relay (ETR)
The ETR feature provides basic telephone services in the event of system failure, such as a
power outage or a failed connection to the MGC. ETR is activated automatically. When ETR is
activated, the Avaya G250/G350 Media Gateway connects the fixed analog trunk port to the first
fixed analog line port (see
Table 92 ). An outside telephone exchange can be connected to the
trunk port and an analog telephone can be connected to the line port. All calls are then directed
by the analog relay between the outside line and the analog telephone. A current-loop detection
circuit prevents ongoing calls from being disconnected when normal functioning resumes. If a
call is in progress on LINE 1 when the problem ends, the call continues. The fixed trunk port and
analog line ports do not start to operate until the active call ends.
The ETR for each of the G250/G350 models closes the tip/ring contacts for the ports listed in
Table 92 .
!
CAUTION:
CAUTION:
Some ports should not be administered as DID ports to avoid having the ETR
“loop-start” trunk connected directly to the tip and ring circuit of the DID trunk,
thus creating two battery feed circuits driving one another.
- G250 . Integrated port V305
- G250-BRI . Integrated port V302
- G250-DCP . Integrated port V305
- G250-DS1 . Integrated port V302
- G350 . Integrated port V702
When ETR is active and the G250/G350 has power, the ETR front panel LED is lit.
Table 92: Emergency Transfer trunk-to-port latching
Gateway model Fixed analog trunk port First fixed analog line port
G350 7/1 7/2
G250-Analog V301 V305
*
* These values are permitted only if they are not previously administered as DID trunks.
G250-BRI V301 V302
G250-DCP V301 V305
G250-DS1 V301 V302