POWER FAILURE TRANSFER (PFT)

Description

Provides service to and from the CO for a limited number of prearranged single-linev o i c e terminals during a commercial power failure (or when voltage drops below 90 volts for longer than 250 milliseconds) and during other service interruptions. Any loop start or ground start trunk may be arranged to terminate at a specific station on a one-to-one basis. When a failure occurs, these prearranged connections are made, bypassing the system and connecting terminals directly to the CO trunks. System features and restrictions are not

available during

this

time.

The

system

supports

up

to four Emergency Transfer Units (ETUs). Each ETU can provide

up

to five

voice

terminals

with direct connection to CO trunks.

When the system connects to dial pulse trunks, only rotary sets may be used to support Power Failure Transfer (PFT). When the system interfaces the CO via touch-tone trunks, touch-tone single-line voice terminals are used as PFT stations.

When power is restored, the following will be restored to their previous state:

1.Night Service mode (on or off).

2.User-programmed Flex DSS numbers.

3. PDCs logged in at a ’’home station” or an ’’away station’’ remain logged in there.

4.If a voice terminal has been removed/not removed from a DGC group, the terminal will remain in that state.

5.User-programmed Repertory Dialing numbers.

6.All system/station features programmed through system administration.

Considerations

Power Failure Transfer provides emergency incoming and outgoing telecommunications service to a number of predesignated single-line voice terminals. This is particularly important for organizations providing public services such as fire, police, medical, etc.

Interactions

None

Administration Requirements

None

Hardware Requirements

The 10B Emergency Transfer Unit (ETU) in Figure 2-35supports up to five Power Failure Transfer (PFT) sets and a DID make-busy function. Up to four ETUs can be supported for a maximum of 20 PFT sets. The sets can be connected to selected Loop Start or Ground Start

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AT&T AT&T manual 189