ATT System 25 Reference Manual

							System Administration
LEGEND:
B1 –
C1 –
C2 –
W1 –
Z3A1 ADU –C3 –355AF ADAPTER –Z3A4 ADU –C1 –
C7 –
248B ADAPTER –
400B2 ADAPTER –
2012D TRANSFORMER –
* MAY NEED LOCAL POWER† FURNISHED BY INSTALLER
Figure 2-59.
TYPICAL-103A CONNECTION BLOCK†MODULAR CORD (D8W-87) - PEC 2725-07G
OCTOPUS CABLE (WP90780) - PEC 2720-05P
4-PAIR INSIDE WIRING CABLE†
EQUIPPED WITH 3-FOOT PLUG-ENDED EIA CORD - PEC 2169-001
EIA CROSSOVER CABLE (M7U-87)
RS-232 RECEPTACLE TO MODULAR JACK
EQUIPPED WITH 3-FOOT RECEPTACLE-ENDED EIA CORD
MODULAR CORDS (2) (D8W-87)
MODULAR POWER CORD (D6AP-87)PEC 62515MODULARIZES 2012D TRANSFORMERPOWER ADAPTER15-18V AC SOURCE
SAT On-Premises Switched Connections
November 19952-325 
						

							Features and Services
LEGEND:
C1 –
C2 –
C3 –
355AF ADAPTER –
MODULAR CORD (D8W-87) - PEC 2725-07G
OCTOPUS CABLE (WP90780) - PEC 2720-05P
EIA CROSSOVER CABLE (M7U-87) - PEC 2724-30C
RS-232 RECEPTACLE TO MODULAR JACK - PEC 2750-A25
Figure 2-60.SAT Off-Premises Direct Connections
2-326November 1995 
						

							System Administration
LEGEND:
C2 - OCTOPUS CABLE (WP90780) - PEC 2720-05P
OPS - OFF-PREMISES STATION
C3 - EIA CROSSOVER CABLE (M7U-87)
355AF ADAPTER - RS-232 RECEPTACLE TO MODULAR JACK
Z3A4 ADU - EQUIPPED WITH 3-FOOT RECEPTACLE-ENDED EIA CORD
C1- MODULAR CORDS (2) (D8W-87)
C7 - MODULAR POWER CORD (D6AP-87)
PEC 62515
248B ADAPTER - MODULARIZES 2012D TRANSFORMER400B2 ADAPTER - POWER ADAPTER2012D TRANSFORMER - 15-18V AC SOURCE
Figure 2-61.SAT Off-Premises
Switched Connections
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							FEATURES AND SERVICES
System Maintenance
Description
The primary objective of System 25 maintenance is to detect, report, and clear troubles as
quickly as possible and with minimum disruption to normal service. This goal is supported
by periodic automatic diagnostic tests and fault detection hardware. System design allows
most troubles to be resolved to the circuit pack level.
System 25 hardware and software are organized as independent units or maintenance
objects. Each maintenance object is normally a separately replaceable unit. These units
include circuit packs, power units, fans, voice and data terminals, cross-connect hardware,
auxiliary, and peripheral equipment.
There are two general categories of system errors:system-detected errors and user-
reported problems.The system can automatically detect and log errors without human
intervention. For system-detected errors, an Alarm LED on the Attendant Console is lighted
if the error qualifies as a Permanent System Alarm (a serious error). Most alarms can be
verified by checking the LEDs located on the front edge of the system circuit packs. (At least
one Red LED will be on.) User-reported problems are usually detected at individual voice
and data terminals and are often related to alarmed conditions.
Alarms may be retired automatically and can also be cleared manually. After a trouble has
been cleared, the system retests the previously faulty area.If the fault is no longer present,
the error message (and alarm, if applicable) is cleared.It is not necessary for maintenance
personnel to retire alarms after a problem has been fixed. However, they may clear error
messages and alarms by entering the proper commands at the System Administration
Terminal.
System Errors And Alarms
If a maintenance object fails periodic tests, the system automatically generates an error
record that is placed in one of three software tables (error logs). The failure may be
classified as a Permanent System Alarm or as an unverified failure that never becomes a
Permanent System Alarm.A Permanent System Alarm causes the Alarm LED on the
Attendant Console to light.This alarm indication is a signal to the attendant to contact
maintenance personnel.
System alarms are classified as:
l Permanent System Alarms: Failures that cause degradation of service and require
Immediate attention. These alarms cause the Alarm LED on the Attendant Console
to light and an alarm record to be stored in the Permanent System Alarm error log.
l Transient System Errors: Potential failures that may cause degradation of service.
These do not light the Alarm LED on the Attendant Console. These are errors that
have not been verified by system self-tests, and are not yet serious enough to be
classified as Permanent System Alarms.
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							System Maintenance
If an error that begins as a Transient System Error is verified or reaches a threshold
level of severity, it is reclassified as a Permanent System Alarm.
Transient system errors are stored in the Transient System Error log. The system
can store a combined total of 40 Permanent System Alarms and Transient System
Errors in the error tables.
l Most Recent System Errors:The ten Most Recent System Errors are recorded by
the system, regardless of their level of severity. These are stored in the Most Recent
System Errors log.
Error Logs
The three error logs can be displayed via the System Administration Terminal. The data in
the log is useful in diagnosing and analyzing troubles, particularly when the problem has not
yet caused an alarm or when alarms cannot be retired by replacement of maintenance
objects.
The error log is historical in nature.It lists faults that have not been resolved as well as past
alarms, and provides a profile of system maintenance.
Automatic Maintenance Tests
There are two kinds of maintenance testing initiated (only) by the system:
l Periodic
l Demand
Periodic tests are run by the system at fixed intervals.The tests do not affect service.
Demand tests are run by the system when it detects a condition requiring a need for testing.
Demand tests are only performed when errors are detected.Maintenance personnel cannot
initiate these tests.
For additional information, see AT&T System 25 Installation and Maintenance Manual.
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							FEATURES AND SERVICES
Tandem Trunking
Description
Tandem trunking provides an enhanced networking capability for System 25. With this
feature, tie trunks can be used to call through System 25 to reach another switching system
(CO or PBX). Calls may be completed over on-network or off-network facilities.
To be treated as tandem trunks, tie trunks must be assigned trunk numbers beginning with
the digit 9. Incoming calls on these trunks may route out of System 25 over ground start,
loop start, or tie trunks. Tandem trunks can gain access to outgoing facilities either indirectly
(by the ARS feature) or directly (by dial access).
System 25’s Tandem Trunking feature does not support traveling class marks or centralized
attendant service.Users cannot activate most System 25 features or services at either the
tandem or far-end terminating switch.
Considerations
The use of tandem
between branches.
Interactions
trunking with tie trunks provides a cost-effective alternative to toll calling
The following features interact with Tandem Trunking.
Automatic Route Selection: Tandem trunk calls that route outbound via ARS receive the
same treatment as calls originated by a System 25 station, with one exception. If all facilities
in a routing pattern are busy, call queuing is not provided.In this case, busy tone is returned
to the calling party.
The second digit of the trunk number is used to specify the trunk’s “station” Facility
Restriction Level (FRL) for use with ARS.FRLs may be specified as follows:
Trunk Number
SecondStation
RangeDigitFRL
9000-91990 or 10
9200-93992 or 31
9400-95994 or 52
9600-99996, 7, 8,3
or 9
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							Tandem Trunking
To gain access to an ARS routing facility, the tandem trunk’s “station” FRL must be equal to
or greater than the route’s FRL. Thus, a tandem trunk with a FRL of 0 has the least ARS
privileges, while a FRL of 3 provides the most privileges.
If the restriction level of the
tandem trunk is less than all route FRLs, reorder tone is returned to the calling party.
Dial Access: No toll restriction is provided for tandem trunk calls. However, access to
outgoing facilities can be controlled via the “allow dial access” option in the outgoing trunk’s
administration.Tandem Trunk calls receive the following treatment when attempting dial
access of System 25 facilities:
l If the requested trunk pool is dial accessible, an outgoing trunk is selected and the
call proceeds normally.
l If the requested trunk pool is not dial accessible, reorder tone is returned to the
calling party.
Any attempt to dial an outgoing trunk pool by non-tandem tie trunks (that is, tie trunks whose
trunk number does not begin with 9) results in reorder tone being returned to the calling
party.
Paging System Access: Tandem trunks can access paging ports (auxiliary or CO trunk
interface), as long as the paging ports are dial-accessible.
Station Message Detail Recording (SMDR): After accessing an outgoing facility, the tandem
trunk’s Facility Access Code (FAC) will be recorded in the STN field on the call’s SMDR
record.If the tandem trunk has no FAC, then the 4-digit trunk number (9xxx) will be
recorded in the STN field. All other SMDR fields are unaffected.
Administration Requirements
Except for the need to specify the trunk number as described above, administration of
tandem trunks is the same as for any other tie trunk.
Hardware Requirements
Only dial-in tie trunks (types 1003-1008) may be used for tandem trunking.
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							FEATURES AND SERVICES
Test
Description
This feature provides users of the 7300H series voice terminals the ability to test their
terminals.
Placing the Test/Program (T/P) switch in the“T” position causes all red and green LEDs to
light alternately and the tone ringer to sound.If the terminal has a display module, the
following responses also occur:
l The display shows 16 darkened squares.
l After the Test switch is returned to its normal position, the Local Display alarm clock
produces 3 short beeps.
Considerations
The Test feature assures users that all visible indicators (LEDs and display screen) and
audible signaling devices (tone ringer, built-in speaker, and timer alarm) of their terminals are
working properly.
The Test switch on some voice terminals is spring loaded; upon release, the switch returns
to a normal on-line position. On other terminals, the switch must be manually returned to the
center (normal on-line) position.
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							Third-Party Call Setup
Third-Party Call Setup
Description
The Third-Party Call Setup feature allows a data terminal (the third party) to set up, via
Command Mode, a call between an on-premises voice or data terminal (the source) and
another voice or data terminal (the destination; can be on- or off-premises). Once the call
has been set up, the third-party drops off and is not included in the call.
Each third-party data terminal may be administered to have a particular source terminal
“associated” with it. This association allows an abbreviated form of dialing when activating
the Third-Party Call Setup feature.Through further administration, the third-party data
terminal may be given permission to set up calls for any source terminal, for only the
associated source terminal, or for no source terminal (feature disabled).
When the user successfully activates Third-Party Call Setup and has dialed all digits
correctly, the following occurs, depending on the source terminal type:
l Voice Terminal (source)
The source voice terminal (if not busy) receives priority ringing. A priority ringing
cycle consists of two short bursts followed by one long burst. The source terminal’s
handset must be picked up within three ringing cycles; the destination terminal will
then be called. Regardless of the call outcome, the third-party data terminal displays
the message CONFIRMED and DISCONNECTED immediately after calling the
destination terminal.
If the source terminal’s handset is not picked up within three priority ringing cycles,
the third-party data terminal displays the messages NO ANSWER and
DISCONNECTED. If the source phone is busy, the third-party data terminal displays
BUSY and DISCONNECTED.
A call to a source terminal that has the Hands-Free Answer on Intercom (HFAI)
feature activated results in the automatic answering of the source end, and the
destination terminal will be called. The third-party data terminal displays CONFIRMED
and DISCONNECTED.
l Data Terminal (source)
If the source terminal is a data terminal whose speed is set to the highest optioned
speed of the data port, the message REMOTE SETUP is displayed at the source
terminal and the CONFIRMED/DISCONNECTED message is displayed at the third-
party data terminal.The destination terminal will then be called automatically from
the source terminal. If the source terminal and destination terminal are compatible, a
data connection is established.
Since the System 25 does not provide call progress tone detection for an off-premises call
(can’t detect second dial tone,for example), pause characters should be inserted at
appropriate places in the dialed digit string.In addition, Third-Party Call Setup calls are
subject to the administered restrictions assigned to the source voice or data port. For
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							FEATURES AND SERVICES
example, if the source terminal is restricted to on-premises calls only, a call to an off-
premises destination terminal will be blocked.
Setting Up A Third-Party Call
To set up a call from the third-party data terminal, the user selects  from the
entry-level Command Mode menu (see Figure 2-58). The user then enters the characters as
required to call the destination terminal.Calls may be completed as follows.
Note:If a character is entered incorrectly, the ASCII character backspace (BS or
CTRL-H keys) or underscore (_) may be used to cancel a previously entered
character.
Calling a Destination Terminal (source terminal is NOT associated with the third-party data
terminal)
After the user has selected  from the Command Mode menu, a DIAL: prompt is
displayed on the third-party data terminal.The user has 15 seconds to begin entering the
digits to be dialed before being disconnected.The format of the digits following the DIAL:
prompt is shown below:
DIAL: {Destination}F{Source}
The Destination number must include all digits required to call the destination terminal and
may contain facility access codes, Speed Dialing codes, and pauses ( V ). An “F” may be
entered immediately following the Destination digits; this character is used to separate the
Destination number from the Source number. The Source number must be a Personal Dial
Code when the source is a voice terminal, or a Data Dial Code when the source is a data
terminal. Floating PDCs are not allowed.
If the user enters the Destination number but not the Source number, the system prompts as
indicated below:
FROM: {Source}
The user must then enter the Source number.
Calling a Destination Terminal (source terminal is associated with the third-party data
terminal)
Following the DIAL: prompt the user enters the Destination number only. (System 25 will
automatically select the associated PDC or DDC as the Source number.)
If the third-party data terminal is permitted to establish calls for any source terminal, the
format {Destination}F{Source}must be used to set up calls for any terminal except the
associated source terminal.
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