Power Fail; Analogue; Isdn - BT Versatility Installation And Maintenance Manual

Power fail

When planning the extension wiring for the system, consideration should be given to the use and location
of Featurephones and 2-wire extensions.

Analogue

In the event of a total system power failure, at least 50% of the equipped lines are switched to extensions.
Lines 1 and 2 are power-failed to extensions 26 and 27, the last two extensions on the basic unit. Line 5 is
power-failed to extension 34 and
Line 7 to extension 35, the last extensions on each of the expansion boards. These line positions are
summarised in the table below.
Note: If lines are power-failed to extension positions equipped with Featurephones, the user must replace
the Featurephone with a standard 2-wire phone to answer or make calls. FEATUREPHONES CANNOT BE
USED IN POWER FAIL.
Line position
Line 1
Line 2
Line 5
Line 6
Line 9
Line 10
Line 13
Line 14

ISDN

In the event of a total system failure, the ISDN lines will not operate. ISDN devices can be connected
directly to the ISDN NTE or an external S bus, and work independently of the system.
Installation and Maintenance Manual
Power-fail extension
Extn 26
Extn 27
Extn 34
Extn 35
Extn 42
Extn 43
Extn 50
Extn 51
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