ATT System 25 Installation And Maintenance Manual

							MAINTENANCE
Memory (ZTN81 [RIV7] or ZTN127 [RI V2]J: The red LED on this CP lights
when power is applied and goes dark upon successful completion of the
ROM checksum test initiated by the Call Processor CP. Failure is indicated
by a steadily lighted red LED.
Call Processor [ZTN82 (R1V1) or ZTN128 (R1V2)]: The green LED on this
CP lights when power is applied and flashes during normal operation. When
the system resets itself, the green LED lights and then goes dark for a few
seconds while the Call Processor performs its self-tests. Once testing is
complete, the green LED flashes and the Call Processor resets all port CPs.
Failure is indicated when the green LED remains steadily lighted or dark.
CPU/Memory [ZTN129 (R2V1) or ZTN130 [R3]; The green LED on this CP
lights when power is applied and flashes during normal operation. When the
system resets itself, the green LED lights and then goes dark for a few
seconds while the CP’s call processor performs its self-tests. Once testing is
complete, the green LED flashes and the call processor resets all port CPs.
Failure is indicated when the green LED remains steadily lighted or dark.
Port Circuit Packs; The red LED on port CP lights during power-up testing
and goes dark upon successful test completion. The green LED lights when
translations have been loaded and remains lighted during normal operation.
The red LED remains lighted for any port CP that fails the start-up test or
fails while in use. The amber LED lights when any port on the CP is in use.
Note:A red LED indicator immediately lights an alarm at the
console for all port CPs except the TN767. Because of the
sensitivity of this CP to noise and transients, a 15 minute
delay exists in lighting the console LED to allow the problem
to correct itself. This will help eliminate service calls for
transient problems caused by weather or noise.
Clock/Service Circuit (ZTN85 or ZTN131 [R3]): The red LED on this CP
lights during self-testing and goes dark upon successful test completion. The
amber LED flashes during normal operation (indicating that the clock
generator is active) and remains lighted when any tone receiver on the CP is
in use. When the amber LED is dark, the CP is not translated or a problem
exists.The green LED lights when translations have been loaded and
remains lighted during normal operation.
November 19954-5 
						

							MAINTENANCE
Attendant Console LED
A lighted green Alarm LED on the console indicates the presence of a
 Permanent System Alarm. The LED flashes with each new alarm. The attendant
can press the associated button to cause the LED to light steadily. A lighted red
Alarm LED indicates a barrier code violation.
Power Supply LED
A lighted green LED on the power supply indicates normal power operation.
Switches and Test Points
The power switch on the back of the cabinet controls cabinet ac power and
should be left in the “On” position (1 =“On”), except when otherwise indicated.
The system has no other field accessible switches, fuses, or circuit breakers.
The power supply contains its own fuses, but these are not field replaceable.
The test points (-5 V, +5 V, 48 V, and GNU) for the power supply are located on
the upper right corner at the front of the cabinet.
System Administration Terminal
The SAT used to administer the system may also be used to read and clear the
error log tables. The error log is read by logging on the SAT, selecting the main
menu item “SEARCH,” and then selecting the table to be read (that is,
Permanent System Alarms, Transient System Errors, or Most Recent System
Errors). To log on the SAT and access an error table, refer to the procedures
provided in “Error Log.”
Remote Initialization and Maintenance (RIM)
Service
Description
The Remote Initial
provides an AT&T
feature, the technic
and maintenance.ization and Maintenance
technician remote access
an can do System 25 initialization, ongoing administration,Service (RIMS) (R2V1 or R3)
to System 25. Using the RIMS
The RIMS port is a logical port on the ZTN129 or
ZTN130/ZTNl 42 (R3) CPU/Memory circuit pack: 
November 1995 4-6 
						

							MAINTENANCE
Using RIMS, the remote administrator can initialize translations after the
switch itself is installed. As long as there is no hardware change, the remote
administrator can do ongoing administration without having to visit the
customer’s site. Similarly, to trouble-shoot a problem, a technician can call
the RIMS port and check the Error Log to determine the cause of the trouble.
The technician can clear alarms remotely and decide whether or not a service
dispatch is necessary.
The remote administrator can establish a call to the RIMS port by one of the
following methods:
l The remote administrator dials the listed directory number (LDN) for
the RIMS trunk. When the call rings at the station (typically, the
attendant console), the called party transfers the call to the RIMS
port. When the RIMS port is connected, the transferring station is
disconnected from the call.
l The remote administrator directly dials the RIMS port using the
Remote Access feature. The Remote Access feature is described in
this manual.
By first dialing a trunk access code, the on-site technician can also establish
a call to the RIMS port using either of the two methods described above.
Considerations
Only one terminal can be connected to the RIMS port at one time. Any
station with a touch-tone dial pad can transfer a call to the RIMS port.
Intercom (station-to-station) calls cannot be connected to the RIMS port.
The trunk connecting to the RIMS port receives busy tone if the port is
already in use.
For transfers, the transferring station receives confirmation
tone if the far end is successfully transferred to the RIMS port. The station
receives reorder tone if there is an error in the transferring sequence.
Interactions
A call to the RIMS port is logged by Station Message Detail Recording
(SMDR).
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							MAINTENANCE
Administration Requirements
For a RIMS call to be made during initialization, at least one voice station and
one trunk must be translated. A cold start with defaults provides these
translations.
The RIMS transfer code (*1 00) can be assigned to a Repertory Dialing feature
button on a multiline voice terminal. If the Remote Access feature is used,
the trunk used for RIMS access must be administered as a remote access
trunk.
Hardware Requirements
Customer’s Site:
None.
.
Remote Location:
A dumb terminal equipped with a modem that supports voice transfer to data
and an RS-232C connecting cable is required. An AT&T PC 6300 replaces
the terminal if the Advanced Installation Tool (AIT) software is used.
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							MAINTENANCE
MAINTENANCE STRATEGY
Fault isolation is the cornerstone of the System 25 maintenance strategy.
Maintenance activity isolates faults to one (or more) repairable or replaceable
maintenance units. Equipment should be tested in the following order:
1.
2.
3.
4.
5.
6.
Terminal equipment
Station wiring
Port circuit packs (CPs)
Common control circuitry
Power supply and cabinet
Backplane.
The first fault isolation step attempts to reproduce the fault, whether it is
system-detected or user-reported.A fault that can be reproduced is more
easily diagnosed and corrected.
Figure 4-1 presents a practical approach in responding to system troubles. If
the maintenance technician is sent to a System 25 site in response to a
trouble report, the maintenance activity will probably consist of isolating and
replacing one or more faulty units of equipment. However, multiple faults
recorded in the Error Log and user-reported troubles may require more
investigation and analysis’.
When the limits of trouble-clearing analysis are reached and the trouble is still
not cleared, the maintenance technician must escalate the problem to a
higher level of technical support.Problems should be escalated to the
National Service Assistance Center (NSAC) in Denver, Colorado. The
telephone number is 1-800-628-2888.
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							MAINTENANCE
SYSTEM
TROUBLE
REPORTEDUSER-REPORTEDDISCUSS THE TROUBLEWITH SYSTEM USERS
CAP ALARM
REPORTED
CAP ALARMED
READ PERMANENT
SYSTEM ALARMS
TABLE IN ERROR
LOG:
AND CHECK
CIRCUIT BOARDS
AND POWER LED
STATUSSYSTEM OR CANNOT
ACCESS ERROR LOG
DEFECTIVE
POWER
SUPPLY
CHECK POWER
LED AND FANS
READ (1) PERMANENT SYSTEM
ALARMS, (2) TRANSIENT
SYSTEM ERRORS TABLE,
AND/OR (3) MOST RECENT
SYSTEM ERRORS IN TABLE
ERROR LOG ;
AND CHECK CIRCUIT
BOARDS AND POWER SUPPLY
LED STATUS CPU/MEMORY
CIRCUIT FRONTPLANE/
BACKPLANE DIAGNOSTIC
REPLACE
POWER
SUPPLY
TYPE OF TROUBLE INDICATED
BY THE LEDS AND ERROR LOG
ERROR LOG CONFIRMS
USER-REPORTED TROUBLE
PORTSPOWER
SUPPLY
CABINET
OR FANSCPU/MEMORY
SERVICE CIRCUIT
FRONTPLANE/
BACKPLANE
DIAGNOSTIC
NO ERROR LOG
RESULTS
RECREATE USER-REPORTED TROUBLE
STATIONS TRUNKS OTHER
ISOLATE TROUBLE TO
REPLACEABLE MAINTENANCE
UNIT (SEE TEXT)RUN
STATION
TEST (S)
SEQUENCERUN
TRUNK
TEST (S)
SEQUENCE
(DEPENDING
ON PROBLEM,
SEVERITY)
FIRST. WARM
START. IF
PROBLEM PERSISTS
RESTORE
TRANSLATIONS
FROM TAPE. IF
PROBLEM PERSISTS
ESCALATE.
Figure 4-1.Response to System 25 Trouble Report
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							MAINTENANCE
Sometimes, faults recorded in the error log and user-reported troubles will
exist at the same time. The logged faults should always be cleared first, if
possible. This procedure often clears the user-reported troubles without any
additional maintenance.
Clearing the most serious logged fault may clear some or all of the other
faults. Descriptions of the errors in the error log section indicate their relative
urgency.
Error log records should be manually recorded before clearing a recorded
error or alarm. If a faulty CP is located in the process of clearing a problem, it
must be replaced with a known good CP. The associated error record should
be included with the CP when it is returned for repair. If the SAT has an
associated printer, the error records can be printed instead of being manually
recorded.
Traditional troubleshooting methods still have a valid place in maintaining a
system as advanced as System 25. And sometimes these methods are
sufficient to locate and clear faults. These methods include voice terminal
substitution,visual inspections,
operating procedures with users.continuity checks,
and clarification of
Total System Failures
As the flowchart in Figure 4-1
circuitry (that is, CPU/Memory
immediately. This procedure mayshows, a failure of
and Service Circu
clear other problems
Port Problems
the common control
it) must be repaired
in the system as well.
Port CP failures can usually be cleared by replacing the CP that has a lighted
red LED (if reseating was unsuccessful). When replacing suspected defective
CPs, wait until the amber LED (indicating CP is in use) goes dark before
removing the pack.
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							MAINTENANCE
Common Control Problems
Common Control circuitry is difficult to troubleshoot. The system must be
powered down before any of these CPs are replaced. Before powering the
system down, save translations to tape (see“Using the Digital Tape Unit”).
Other repair procedures may also require the system to be powered down.
After removing a suspected faulty CP, do the following:
l Visually inspect the CP.If a problem is identified, attach a note to
the CP identifying the problem.
l Attach any error reports that may apply.
l Visually inspect the cabinet backplane.
After the suspected faulty CP has been replaced, the system can be powered
up. When the CPU/Memory CP is replaced, all historical data is lost. The
system will then have to be restored from the tape backup unit with the latest
copy of the system’s translations.If no tape exists, the system has to be
reinitialized.
Multiple errors and off-board errors are more likely to occur in common
control problems than in port problems.Use of the Error Log is imperative
in clearing common control problems.
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							MAINTENANCE
Station, Wiring, and Trunk Problems
If the system indicates that a fault is with a station, or if a user complaint
indicates a station problem, the trouble must be isolated to the station itself
or to the wiring between the cabinet or station interconnect panel and the
station.
The station wiring, particularly the mounting cord, should be visually
inspected in cases of station trouble reports. A dead station could be caused
by a loose mounting cord.Station trouble can also occur when wiring is
crushed or severed by furniture or traffic. Stations can be swapped with
known good stations of the same type to help isolate the trouble.
Trunk problems reported by alarms or by users can be evaluated with tests
from stations or by interpreting the error log. If trunk troubles appear to be
outside the System 25, the responsible common carrier should be asked to
make repairs.
Automatic Maintenance Tests
Because System 25 maintenance tests are performed automatically, no
provision is made for users or technicians to initiate maintenance tests. The
error log is read by entering commands from the SAT. Additional information
that may help in clearing complex or subtle troubles is also available through
the SAT (for example, the record of port locations).
Refer to the Administration Manual (555-540-500) for information on using
“Search” procedures from the SAT as an aid in troubleshooting.
Maintenance Failure
If a System 25 equipment problem cannot be corrected using the procedures
in this manual, follow established maintenance escalation procedures.
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							MAINTENANCE
USING THEDIGITAL TAPE UNIT
The Model DC4 Digital Tape Unit (DTU) or equivalent is extremely important
in system maintenance. System Translations are stored in the DTU and can
be accessed in the unlikely event that translations are lost during a system
failure.
This section covers the following:
l Setting Up the DTU
l Saving Translations
l Verifying Translations
lRestoring Translations.
Setting Up the DTU
The DTU must be properly connected to the system before it can be used.
Refer to Section 2,
“Installation” in this manual for connection information.
The DTU automatically turns on when ac power is applied.
The DTU must also be connected to the CPU/Memory CP. Normally, this
connection is made through port 3 in the octopus cable originating from the
CPU/Memory CP. This connection should be verified, however, because the
port can be reassigned from the SAT.
A high quality audio cassette tape should be used. Examples of acceptable
tapes are the Maxell UD XL-II C60 or C90, and the TDK SA C60 or C90.
Before operating the DTU, always follow these steps:
1.
2.
3.
4-14Press the STOP/EJECT button on the unit. (The plastic cover pops
up.)
Insert the cassette so the exposed portion of
unit’s buttons.Press the cassette downward
place.
Close the cover.the tape faces
until it snapsthe
into