ATT System 25 Reference Manual

Pooled Facility - Dial Access
Administration Requirements
Voice Terminal Port:
l Restrictions - Refer to “Calling Restrictions” feature description.
Trunk Port:
l Assign facility access codes.
l Allow dial access for facility (yes or no).
November 19952-259 

Features and Services
Pooled Facility - Direct Access
Description
This feature allows multiline voice terminal users to access a common pool of trunks via a Direct
Facility access (FACILITY) button.
Upon pressing a FACILITY button and going off-hook, a multiline voice terminal user is connected
to a common pool of outside trunks (i.e., CO, FX, WATS, tie). If the Status and I-Use LEDs
associated with the button light steadily, the user may complete the call. If no idle trunk is available
(facility busy...

Pooled Facility - Direct Access
Administration Requirements
Voice Terminal Port:
l Assign Direct Facility Access (FACILITY) buttons.
l Restrictions—Refer to “Calling Restrictions” feature description.
Trunks:
l Assign Facility Access Codes.
l Allow dial access for facility (yes or no).
November 19952-261 

Features and Services
Power Failure Transfer (PFT)
Description
This feature provides service to and from the CO for a limited number of prearranged single-line
voice 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...

Power Failure Transfer (PFT)
Only FCC registered single-line voice terminals may be used for PFT stations. Rotary sets
must be used for dial pulse PFT trunks; touch-tone sets must be used for touch-tone PFT
trunks.
In the event of a Power Failure Transfer (switch has lost power or a major fault has
occurred) a contact closure is provided to the Central Office (CO) over a dedicated pair of
wires.The CO then makes busy all DID trunks.
When power is restored, the closure is
removed and the CO restores DID...

FEATURES AND SERVICES
Figure 2-38.10B Emergency Transfer Unit (ETU)
2-264 

Power Failure Transfer (PFT)
SYSTEM 25
CABINET
TRUNK
PORTTAE
CALLPROCESSOR
ETU
ETU TO SWITCHETU TO
25-PAIR(TRUNK)CO
-48V
CPU
TOADDITIONALADDITIONALETUsETU
CENTRAL
OFFICE
25-PAIR
OCTOPUS
ETU TO SWITCH(LINE)
ETU TO
SIP
STATION
PORT25-PAIRCABLE
PART OF SIP
858A
ADAPT.
UP TO FIVE POWER FAILURE
TRANSFER (PFT) STATIONS
(REGISTERED SINGLE-LINE)
(a) ETU CONNECTIONS (DASHED LINES) NORMAL OPERATION - (NO PFT)
(TRUNK SUPPORTS STANDARD CO CALLS)
ETU
TAE
-48V REMOVEDCENTRAL
OFFICE25-PAIR
TO PFTSTATION
(b) ETU...

FEATURES AND SERVICES
NOTES:
1. TRUNK AND STATION CONNECTIONS TO ETU 2-4 ARE SIMILAR TO ETU (1).
2. THREE OF EIGHT STATION LINES (FROM ANALOG STATION CP) AND THREE OF EIGHT TRUNKS
(FROM CO TRUNK CP) WHEN USED ARE“FED-THROUGH” ETU, THEY ARE NOT SWITCHED IN THE EVENT
OF A POWER FAILURE.
3. MAXIMUM ETU(S) = 4, MAXIMUM PFT STATIONS PER ETU = 5.
Figure 2-40.Multiple ETU Arrangements
2-266 

Program
Program
Description
This feature enables system users to store numbers for access by feature buttons or code
dialing. Multiline voice terminal users can program numbers on REP DIAL and FLEX DSS
buttons.Both multiline and single-line terminal users can store Personal Speed Dialing
numbers. FLEX DSS buttons provide access to inside extension numbers only; REP DIAL
buttons and Personal Speed Dialing are used for account codes and outside numbers
(maximum of 28 digits and 25 digits, respectively)....

FEATURES AND SERVICES
CHAR.USED IN PERSONAL SPEED DIALING NUMBERS
VProduces a 1.5 second pause.
—  Since System 25 does not have a Dial Tone detector,
judicious use of the pause character will help to ensure that
intermediate Dial Tones are obtained before more digits are
sent.
—
The pause character should not be programmed for internal
calls.
# V
Transmits an actual “ V ”.
# #Transmits an actual “ # ”.
# 1xxRepresents a System Speed Dialing code (where xx = 00-89) or a
Virtual Facility code (where xx=...