BT BT Versatility manual 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	Power-fail extension
Line 1	Extn 26
Line 2	Extn 27
Line 5	Extn 34
Line 6	Extn 35
Line 9	Extn 42
Line 10	Extn 43
Line 13	Extn 50
Line 14	Extn 51

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.

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