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...

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...

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...

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...

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...

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...

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,...

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...

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...

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...