ATT System 25 Maintenance Manual

							CLEARING USER-REPORTED TROUBLES
Note:For problems with administration equipment that is not connected
on a dedicated basis, refer to the Terminal Operations Manual (555-
520-710).
Time-Keeping Troubles
Symptoms:
Clock doesnt reflect current time or date.
Procedures:
1.Reset clock from SAT (see the Administration Manual for your
system). Clock has tolerance of +/- 3 minutes per month. Variances
outside this range indicate a faulty clock and require replacement of
the Call Processor. Time must be reset for Daylight Savings Time.
Voice Terminal and Wiring Troubles
Symptoms:
Intermittent voice terminal troubles.
Procedures:
1.
2.
3.
4.
5.
Swap a known good terminal with the questionable terminal to
determine if problem is localized to a single terminal. If local power is
provided, check power supply.
If troubles do not persist, problem is localized to single terminal.
Replace faulty terminal.
If good terminal does not work properly, fault is in wiring or circuit
pack (CP).
Check other terminals connected to same CP. If other terminals are
working properly, fault is probably in wiring. Swap wiring between
Station Interconnect Panel and terminal to verify wiring problem.
Check and clear any wiring problems.
If other terminals connected to same CP are not working properly,
fault is probably in CP.
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							CLEARING USER-REPORTED TROUBLES
6.Check CP translations from the SAT to be sure this CP has been
properly translated.
7.Check LEDs on CP. Red light-emitting diode (LED) is lighted if there
is a fault on the CP that affects all ports but may be lighted if one or a
few ports are faulty.
8.Check error log for relevant messages.
9.Reseat the CP, whether or not the red LED is lit. (See Reseating
and Replacing Circuit Packs in Section 8.) Replace faulty CP.
Voice Transmission Troubles
Symptoms:
Voice terminals not receiving tone transmission.
Procedures:
1.Check that green LED on power supply is lighted.
2.Check power supply for voltages.
Symptoms:
Many single-line sets or multibutton electronic telephone (MET) sets
are not able to dial correctly even though they are able to receive
calls.
Procedures: Using a single-line set, do the following to test touch-tone
registers:
1.At a single-line voice terminal, go off-hook, dial *3 and the 2-digit
number (01 through 12) of the touch-tone receiver to be tested.
Receivers 01 through 04 are on the ZTN85 CP. Receivers 05 through
12 are only present if your system has TN748 CP(s).
—
You will hear busy tone if the receiver is in use. You will hear
reorder tone if you misdialed or addressed a receiver not in
your system (for example, you dialed *305 and your system
does not have a TN748 CP). Try again.
—
If you hear dial tone, proceed with this test.
2.Dial the digits 1 2 3 4 5 6 7 8 9 0 * #.
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							CLEARING USER-REPORTED TROUBLES
—
—You should hear a DTMF signal as each key is pressed.
You will hear dial tone one to three seconds after entering the
# if the test passes.
3.Repeat the test for each touch-tone receiver.
4.Replace the Service Circuit CP if this test fails.
7300H Series Terminal Troubles
Symptoms:
7300H Series terminal LEDs and/or tones not functioning properly.
Procedures:
1.Move the T/P lever on the left-hand side to the T (Test) position
and hold it there.
2.Tone ringing should be heard.
3.All the red and green LEDs on the terminal should flash alternately
while the lever is held in this position.
4.Release the lever, letting it return to its normal position.
5.Ringing tone should be silenced and LEDs extinguished.
6.If any part of the test fails, the terminal is faulty and should be
replaced.
Symptoms:
Set keys dont click.
Procedures:
1.Check to be sure appropriate ZTN79 CP is translated.
2.Check for presence of -48 volts at power supply.
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							CLEARING USER-REPORTED TROUBLES
Trunk Troubles
Many trunk troubles originate in the central office (CO) facilities. The first step
in identifying trunk troubles should be to check for presence of dial tone at
the Trunk Access Equipment (TAE). If required, check the error log records,
and make a trunk test call.
Note that it is sometimes difficult for the user to detect or identify trunk
troubles. If an outgoing trunk is down, an error is recorded in the error log
and the trunk is taken out of service (see Note below). If an incoming-only
trunk is down, however, the only manifestation of trouble is customer
complaints that incoming calls are not being answered.
Note:
For Version 2 systems, the system will not busy out more than half
of the trunks in any pool. Thus, a permanent alarm may be logged
against a particular trunk, but the trunk may not be taken out of
service because of this constraint.
Outging Trunk Problems
Symptoms:
Difficulty is seizing outgoing trunks.
Procedures:
1.
2.
3.
4.
5.
Verify that dial tone is received from the CO at the TAE (see Note
below). If no dial tone is present, notify the CO through the proper
channels.
Note:For ground start trunks, you must apply ground to the Ring
lead to get dial tone.
Go off-hook at a test station and get system dial tone.
Dial *2 (the test code for all non-DID facility trunks).
Dial the 4-digit trunk number of the trunk to be tested. (This is the
same number used by the System Administrator to identify this trunk.)
Listen for dial tone from the accessed trunk. If dial tone is not
present, isolate the fault to a trunk port CP or location in the trunk
access equipment, etc., using a test set.
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							CLEARING USER-REPORTED TROUBLES
6.If dial tone is present, dial a working outside number. Verify that the
call is complete.
7.If trunk is busy, fast busy tone is heard. If a non-port trunk was
dialed, fast busy tone is heard.
Incoming Trunk Problems
Symptoms:
Incoming trunks (of any type) not working properly.
Procedures:
1.Place an incoming call through the troubled trunk.
2.Check the trunk translations via the SAT to be sure this trunk has
been properly translated. (See the Administration Manual for your
system.)
Error Log Interpretation: Loop Start Trunks
Procedures:
1.
2.
3.
4.
5.
6.
7.
Check error log for messages pertaining to loop start trunks.
If no loop current on incoming call is displayed, no loop current
was detected on an incoming call. The CP detected ringing, but not
loop current when it closed the loop. In this case, the CO facility is
probably good, but either the current sensor on the CP is faulty or the
CO battery circuit is faulty.
Switch trunk ports and see if the problem moves to the new loop start
trunk.
If the problem does not move, the loop start CP is faulty and must be
replaced.
If the problem moves, the fault is with the CO and should be notified
through the proper channels.
If no loop current on outgoing call is displayed, either of the above
conditions could be true. It is more likely, however, that the facility is
down.
Place an outside call on the line using the trunk test call steps under
Outgoing Trunk Problems. If you get fast busy tone, switch trunk
ports and try again.
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							CLEARING USER-REPORTED TROUBLES
8.If the problem does not move, the loop start CP is faulty and must be
replaced.
9.If the problem moves, the fault is with the CO. Notify CO personnel
through the proper channels.
Error Log Interpretation: Ground Start Trunks
Procedures:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Check error log for messages pertaining to ground start trunks.
If “no loop current on incoming call” is displayed, no loop current
was detected on an incoming call.The CP detected ringing, but not
loop current when it closed the loop. In this case, the CO facility is
probably good, but either the current sensor on the CP is faulty or the
CO battery circuit is faulty.
Switch trunk ports and see if the problem moves to the new ground
start trunk.
If the problem does not move, the ground start CP is faulty and must
be replaced.
[f the problem moves, the fault is with the CO and should be notified
through the proper channels.
If “fault on outgoing seizure”is displayed, either of the two
conditions is true. The first condition is that the trunk CP did not
detect loop current as in the case of the “no loop current on incoming
call” message.The second condition is that the trunk CP did not
detect Tip ground. This could be either a problem with the CO or the
ground detector on the CP.
Place an outside call on the line using the trunk test call steps
“Outgoing Trunk Problems.”If you get fast busy tone, switch trunk
circuits and try again.
If the problem does not move, the ground start CP is faulty and must
be replaced.
If the problem moves, the fault is with the CO. Notify CO personnel
through the proper channels.
If “Ringing no ground”is displayed, the T and R leads may be
reversed in the trunk access wiring. The T lead should have ground
and the R lead should have -48 volts. These can be verified by
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							CLEARING USER-REPORTED TROUBLES
reversing the ground and ring leads and checking with either a
voltmeter or a test set (with a polarity switch). A voltmeter should
indicate a presence of 48 volts. A test set should provide dial tone
when temporarily grounding the Ring lead.
11.“Ringing no ground” may also mean that the ground detect circuit on
the Ground Start CP is faulty. Check and replace this CP if necessary.
12.“Ringing no ground”may also mean the CO is unable to send
ground. If this is the problem, notify the CO through the proper
channels.
DID Trunks Troubles
Symptoms:
User complaints that direct inward dialing trunks are not operating
properly (for example, callers hear trunks ring, but users hear no
ringing at voice terminals).
Procedures:
1.Check the trunk translations via the SAT to be sure that trunks have
been properly translated. (See the Administration Manual for your
system.)
2.Check the error log for messages such as:
l Rotary dial before wink
l Rotary dial pulse too early
l Rotary dial pulse during wink
l CO failure to release after PBX disconnect
l CO belated release.
These messages indicate CO problems. The first three errors are
very common when DID trunks are installed. The CO should be
notified through the proper channels about any of these problems.
3.CO failure to release after PBX disconnect can frequently be
corrected by disconnecting and then reconnecting the DID trunk. If
this procedure does not resolve the problem, notify the CO through
the proper channels.
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							CLEARING USER-REPORTED TROUBLES
4.
5.
6.
7.
8.
9.
Check each suspect DID trunk port by dialing in with the touch-tone
test set beginning at the network interface. (Be sure to use the
appropriate dialing mode: dial pulse or rotary.)
If the test call is successful at the network interface, the fault is
probably with the CO facility, and the CO should be notified through
the proper channels.
if the test call is not successful at the network interface, repeat this
test at the cabinet.
If the test fails at the cabinet, the DID circuit pack is faulty and must
be replaced.
If the test call is successful at the cabinet but not at the network
interface, the trunk access equipment wiring is faulty and must be
repaired.
Check the error log for any messages indicating unused (inaccessible)
DID trunks.
Special Port Circuit Options for Stations and
Trunks
Tables 9-A and 9-B provide the special port circuit options that are
administered in the system. System defaults and associated action codes
applicable to the various port CPs are also shown. Procedures are available
in the Administration Manual for your system for logging on the system and
accessing the information shown in Table 9-A. The administrable items
shown on Table 9-A should not be changed unless CO and maintenance
personnel agree that an item needs changing.
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							CLEARING USER-REPORTED TROUBLES
Table 9-A.Station/Trunk/Special Port Circuit Board Options
CIRCUIT BOARD OPTIONS
(See Applicable Actions—Table 9-B)
ACTIONDESCRIPTION
CO Disconnect time
(in 20 msec
increments)
End-To-End
Signaling Tone
Timing (in 20 msec
increments)
DATADEFAULT
32(0-2540) Msecs[500]
33(0-2540) Msecs[60]
[60] End-To-End
Signaling Pause
Timing (in 20 msec
increments)
(0-2540) Msecs34
1 - Resistor
0 - Resistor/Capacitor35Hybrid Balance
[*]
1 - Gain = 3db
0 - Gain = 0db
36Gain[0]
E&M Signaling Type2 - Type I Compatible
1 - Type V
2 - Type I
37[2]
38Answer Supervision
Delay Timing(0-5100) Msecs
[300]
* Default depends on CP type. Trunk ports are defaulted to 0 (RC
termination) while station ports are defaulted to 1 (R termination).
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							CLEARING USER-REPORTED TROUBLES
Table 9-B.Applicable Actions for Circuit Board Options
ACTIONS FOR CIRCUIT BOARD OPTIONS
(See Circuit Board Options—Table 9-A)
CIRCUITBOARDACTIONS
BOARDTYPE32333435363738
ZTN76GS Boardllll
ZTN77LS Trunkllll
ZTN78Tip/Ring Linell
TN742Analog Linellll
TN753DID Trunkllll
TN760BTie Trunklllll
TN763Aux. Trunkll
Data Line Troubles
Symptoms:
Data terminals connected via the data line card (TN726) dead or not
functioning properly.
Procedures:
1.
2.
3.
4.
5.
Check that the RS-232C connector onthe Asynchronous Data Unit
(ADU) is properly connected to the RS-232C connector on the data
terminal.Always tighten the screws or other fasteners on the
connectors.
Check terminal ac power connection.
Check to be sure connection to ADU is 4-pair modular plug.
Check ADU ac power connection (see Steps 5, 6, and 7). Note that
any ADU connected to a port on the Call Processor must have a local
ac power source. Briefly disconnect the ADU’s power cord.
If ADU is not externally powered, check pin 20 (DTR signal on the
RS-232C connector) for presence of at least +7 volts relative to pin 7
(ground).
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