AT&T LT-2 Guide

AT&T 356-024-510
Issue 1
Provisional
Task Oriented Practice
(TOP)
LT-2 DIGITAL TRANSMULTIPLEXER
MAINTENANCE
Copyrighte19S4AT&TTechnologies
All RightsReserved
Printedin U.S.A.
TPG-()()0
Page 1of 1

AT&T 35&024-5 10
18sve1 m-m 1
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TASK INDEX LIST
FIND YOUR JOB IN THE LIST BELOW. . . . . . . . . . . . . . . . . . . . . . .. THEN GOTO
-10 DBMO Test Tone Toward Analog Facility for Far-End Trunk Adjustment —
-10 DBMO Tone Toward Digital Facility for Far-End Digital Tests –Send .
Control and Access Unit –Initialize . . . . . . . . . . . . . . .
DATS For Circuit Tests —Connect . . . . . . . . . . . . . . .
Daisy-Chain Problem —Clear . . . . . . . . . . . . . . . . .
Digroup in 48-Channel Module –Establish ............
Digroup in 96-Channel Module –Establish . . . . . . . . . . . .
Echo Canceler Circuit Pack(s) –Install .............
Echo Canceler Option to Digroup –Add . . . . . . . . . . . . ,
Echo Canceler Test –Conduct . .
Failed Fan –Replace .....
Fan Air Filter –Replace . . . .
Fuse Alarm –Clear . . . . . .
Fuse(s) in 39C Fuse Block –Install
J-68967A LT-2 Digital Transmultiplexer
Maintenance Philosophy . . . . .
Major Alarm –Clear . . . . .
Minor Alarm —Clear . . . . .
Or Remove Circuit Pack –Install .
Power Converter Unit(s) –Install
Provisioning Data from CAU to CH-PR
Send . . .
. . . . . .
......
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. . . . . .
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. . . . . .
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.....................
.....................
. . . . . . . . . . . . . . . . . . . . .
.....................
Framework Assembly –Accept .......
.....................
.....................
. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .
–Download . . . . . . . . . . . . . . .
DLP-522
DLP-523
DLP-509
DLP-520
TAP- 104
NTP-005
NTP-004
DLP-513
NTP-007
DLP-515
DLP-525
DLP-526
TAP- 103
DLP-505
NTP-003
TAD- 100
TAP-101
TAP- 102
DLP-519
DLP-507
DLP-524

:
IXL-001 AT&T 356-024-510
Page 2of 2ISSU91
FIND YOUR JOB IN THE LIST BELOW. . . . . . . . . . . . . . . . . . . . . . .. THEN GOTO
Provisioning Data from CH-PR to CAU –Upload . . . . -. . . . . . . . . . . .
Receive Gain At LT-2 Equipped With SL174 Channel Processor Unit (DATS Not
Required) -Align . . . . . . . . . . . . . . . . . . . . . . . .
SL112VF Access Unit– Test. ......................
Signaling Circuit Packs –Install ......................
Signaling Option to Digroup -Add .....................
Signaling-type Parameters(s) –Change ...................
Software Provisioning –Perform ......................
System Overview and Acceptance . . . . . . . . . . . . . . . . . . . . . .
DLP-504
DLP-511
TAP -105
DLP-512
NTP-006
DLP-514
DLP-51O
NTP-002

AT&T33&024-510
ksuel NTP-002
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SYSTEM OVERVIEW AND ACCEPTANCE
SYSTEM OVERVIEW
A. Generol
The LT-2 is an intelligent terminal, employing microprocessors to provide user communication with the bay.
The built-in microprocessors allow remote control of circuit parameters including via net loss, channel level
adjustment, echo control, and signaling conditioning. Also, the microprocessors control alarm collection and
channel access for maintenance. The user can communicate with the LT-2 by using akeyboard terminal. A
number of bays can be connected together to enable the circuit provisioning of all bays from one location.
The LT-2 continuously monitors its own circuits by means of self-generated looping tones which detect
failures in circuit packs.
B. MkroproeessorControl Hierorchy
Each LT-2 bay contains one microprocessor located in the Control and Access Unit. This unit serves as the
bay communicator to the user and may be mounted in any powered shelf in the bay. This unit also
communicates with up to 16 other microprocessors, one per equipped Channel Processor Unit. Each of these
digroup level microprocessors responds to commands from the Control and Access Unit.
C. 11-2 Communicat.wn Access
T%ere are two ways to access an LT-2 bay. One is over the daisy-chain connector (on the distribution panel
at the top of the bay) which is used to link bays together and provide communication access to multiple
bays via asingle data bus. The other method is through the Control and Access Unit (CAU) faceplate
connector, providing single bay access. Abay can be accessed through only one of its connectors; i.e., daisy
chain or CAU faceplate, at any one time. The CAU faceplate connector access takes precedence over the
daisy-chain connector.
Bay communication via the daisy chain is inhibited once bay communication via the CAU faceplate
connector is granted. To establish bay communication via the CAU faceplate connector, connect aterminal
to it and depress any key. Faceplate control is granted (indicated by aREADY message on the terminal
plugged into the faceplate) once any communication in progress is completed by that bay. ABAY GOING
OFF-LINEmessage is transmitted from the link connector on that bay. To restore daisy-chain communication
to the bay, unplug the terminal from the CAU faceplate connector. ABAY BACK ON-LINE message is
transmitted over the daisy chain by that bay,
The LT-2 bay must be part of an active daisy chain before it can grant CAU faceplate control with the READY
message. If this message does not appear on the terminal, the daisy chain probably is not complete to the
main LT-2 keyboard terminal or modem (which connects to the daisy-chain connector on the first bay in the
lineup). However, faceplate control can be obtained by pressing the RESETbutton on the CAU after the termi-
nal is connected to the CAU faceplate connector.
An on-line bay is one which communicates via the daisy-chain data bus. An off-line bay is (1) one which has
been accessed through its CAU faceplate connector, (2) one with an insane CAU: the sanity timer has
expired, lighting the ALM light-emitting diode (LED) on the Control and Access Unit, or (3) one without a
powered-up CAU.
Abay that has been accessed via its CAU faceplate connector or one that has gone insane does not break
the daisy-chain data bus communication for any other bay. However, abay without apowered-up CAU

NTP-002 AT&T 356-024-510
Pag*20f3 Issuo 1
breaks the daisy chain at that bay, resulting in none of the subsequent bays (bays farther away from the
daisy-chain terminal than this off-line bay) being able to communicate via the daisy-chain data bus. If this
condition occurs, the daisy-chain break can be temporarily bypassed by unplugging the two data-bus cables
from the two daisy-chain connectors on the distribution panel at the top of the bay and plugging these two
cables together. This restores daisy-chain continuity to the subsequent bays.
With daisy-chain communication, all on-line bays are listening to commands as they are being entered.
Either one or all bays can be addressed in asingle command. Once an addressed bay begins its response, it
will complete its output before another bay begins its response. The addressed bays will not necessarily
respond in the same order as their daisy-chain lineup positions.
In adaisy-chain environment, one bay is the echoing bay. This bay echoes each character entered at the
daisy-chain terminal and reports any syntax errors via the daisy-chain data bus. The echoing bay is the last
on-line bay, i.e., farthest from the daisy-chain terminal, in the daisy chain. If the echoing bay goes off-line,
the next preceding on-line bay becomes the echoing bay- When echo is passed to the next preceding on-line
bay, an ECHO TRANSFERREDTO THIS BAY message is transmitted over the daisy-chain data bus by the new
echoing bay.
If anonechoing on-line bay goes insane, the next preceding on-line bay becomes an echoing bay. This results
in aduplicate echo over the daisy-chain bus, since the original echoing bay continues to echo.
D. General Operating Information
Baud rate of the daisy chain is determined by the communication device (modem, TTY, etc.) attached to tha-
daisy-chain bus. The baud rate switches must be set on the Control and Access Unit in each and every bay
to be consistent with the daisy-chain baud rate. The baud rate of any device plugged into the Control and
Access Unit faceplate connector must be consistent with the faceplate baud rate switch settings on the
Control and Access Unit.
E. Handheld Terminal
The Type 12 pocket terminal has multifunction keys on its keypad. To activate the second function of akey
(printed in white on ared background), press the SHIFT key at the top left-hand corner of the keypad before
pressing the desired function key. If you make amistake, you can backspace by pressing CONTROL Hor
SHIFT3, or you can delete the whole line by pressing SHIFT @. Processes can be stopped using CTRLX(CONTROL
X), which invokes the same function as CANCELor DELETEon most full-sized terminal keyboards.
If for some reason the user cannot regain control of the system, CTR1O(Control “Zero”) will abort’ all
processing. This invokes the same function as BREAKor ESCAPEon most full-sized terminal keyboards.
Caution: The use of CTRlO,BREAK,or ESCAPEis intended as ararely-used immediate
halt. Use of this function may cause database inconsistencies between the CA U
and CH-PR. For this reasonj C4NC& DELET4or CONIROlXare the preferred halt
functions. Recovery from this type of abort should include an examination of the
CA Uand CH-PR data bases for consistency. Test setup status should also be
examined.
F. Helpful Hints far SuccessfulCommand Usage
Only one command may be entered at atime. All requested processing for acommand must be completed
before the next command is entered. Entering anew command before processing has been completed by all
bays addressed by the previous command, can produce unpredictable results.
Sometimes auser might enter acommand and not receive aresponse or an error message. This will most
likely happen if the user enters avalid command with avalid address format, but the address used does not
belong to any of the bays on the daisy chain. Each bay reads the command line, recognizes the command

A7&T 356-024-510
Issue 1NTP-002
Page 3of 3
line as being valid, but ignores the command because the address does not match its own. Since all of the
bays on the daisy chain ignore the command, the user receives no response or error message.
An LT-2 bay, equipped with at least one digroup, contains-two storage locations for provisioning data. One
storage data base is located in the Control and Access Unit and the other is located in the Channel
Processor Unit of each digroup. When the changing or copying of data in any of these locations is
completed, the user should ensure that the data stored in the Control and Access Unit is the same as the
data stored in each of the Channel Processor Units. This practice maintains abackup memory for the data
stored in the bay.
If aControl and Access Unit is replaced with aspare unit, use the UL (UpLoad) command addressed to that
bay to copy the provisioning data from all Channel Processor Units in the bay up to the new Control and
Access Unit. Until the UL command is used to copy the data into the Control and Access Unit, the user
should be aware that the only backup for the provisioning data will be paper records.
If aChannel Processor Unit is replaced with aspare unit, use the DL(DownLoad) command addressed to
that digroup to copy the provisioning data from the Control and Access Unit down to the new Channel
Processor Unit. Until the DLcommand is used to copy the data to the Channel Processor Unit, the user
should be aware that the only backup for the provisioning data will be paper records.
PAPER RECORDS SHOULD ALWAYS BE KEPT FOR ALL PROVISIONING DATA IN ALL BAYS EVEN
IF BOTH DATA BASE LOCATIONS IN EACH BAY CONTAIN THE SAME DATA.
With an SL174 Channel Processor Unit, channel gain may be pre-service adjusted by temporarily installing
adigroup into the necessary bay location and conducting the auto-gain adjustment using the AG (Auto-
Gain) command. Upon completion of channel gain adjustment, the AG command stores the gain coefficients
for each channel in both the Control and Access Unit data base and the Channel Processor Unit data base.
A$er adjusting the gains, the temporary digroup circuits may be removed and used to pre-service adjust
another digroup location. However, the Control and Access Unit should remain in the bay. When the
permanent circuits arrive and are installed, the DL(DownLoad) command can be used to copy the gain
coefficients (and other provisioning data, if desired) from the Control and Access Unit down to the new
digroup Channel Processor Unit.
11-2 ACCEPTANCE PHILOSOPHY
The acceptance procedure for the LT-2 Digital Transmultiplexer frame is designed to verify that the bay
has been installed properly and that the communication panel (if installed) is operating properly. Since the
frame is shipped without circuit packs, circuit packs are tested as part of circuit order work requiring their
installation.
Acceptance procedures do not contain any trouble-clearing information. If trouble is encountered or if
requirements are not met, contact the responsible installation group.
All procedures are based upon the assumption that any specified test apparatus is functioning properly and
is conditioned and connected correctly.
LIST 1-11-2 DIGITAl TRANSMULTIPL.EXERACCEPTANCE TASK
Accept J-68967A LT-2 Digital Transmultiplexer Framework Assembly ......... NTP-003

1
NTP-003
Pago 1of 1
ACCEPT J-68967A 17-2 DIGITAL
TRANSMULTIPLEXER FRAMEWORK ASSEMBLY
AT&7 356-024-510
Issuo 1
DO ITEMS BELOW IN ORDER IJSTED ................. FOR DETAILS, GO TO
1. Note: R&er Any Problems to AT&T Installation Group
Perform Visual Inspection of Frame, Hardware, Cabling, Wiring, and Connectors DLP-500
2. Test Operation of ED-54845 Communication Panel, if Installed DLP-501

AT&~ 35~4-510
Issue 1NTP-004
Pogelofl
ESTABLISH DIGROUP IN 96-CHANNEL MODULE
DO ITEMS BELOW IN ORDER LISTED.. ............... FOR DETAILS, GO TO
1. Warning The LT-2 Circuit Packs Contain Static-Sensitive Components
Which Could Be Damaged by Electro-Static Discharge. Before Unpacking
or Handling Circuit Packs, Refer to Special Handling Preca utions in Section
032-173-301.
2. Connect Wrist Strap Between Wrist and LT-2 Bay DLP-502
3. Install Basic Digroup Circuit Packs DLP -503
4. Install Fuse in 39C Fuse Block. for Digroup Being Installed DLP-505
5. From Office Records, Determine if Signaling or Echo Canceler Options Are Required
(Either Signaling or Echo Cancelers, or Neither)
A. Install Signaling Circuit Packs (Two per Digroup) :DLP-512
B. Install Echo Canceler Circuit Pack(s) (One per Group) :DLP-513
6. Warnin& Do Not Install More Than One CA UPer Bay. Each Bay Requires
One Control and Access Unit (CA U) Mounted in CA UPosition of One and
Only One Shelf
If Not Already Installed, Install Control and Access Unit DLP-508
7. Install Power Converter Unit(s) DLP-507
8. If Not Already Installed, Install SL106 Alarm Unit DLP-506
9. If Not Already Initialized, Initialize Control and Access Unit DLP-509
10. If Parameter Data Is To Be Entered from Remote Office, Update Office Records to
Reflect Work Completed and Ignore Remaining Items in This Procedure
11. Enter Channel Signaling, Via-Net-Loss (ICL), and Echo Canceler Parameters DLP-51O
12. Establish Communication with Office at Far End of Analog Facility and Request
Assistance in Performing Item 13
13. Align Receive Gain (Do Aor B, not Both)
A. At LT-2 Equipped with SL114 Channel Processor Unit (CH-PR) (Using DATS DJ.P-521
L1,LB or Li MOD A) :
B. AT LT-2 Equipped with SL174 Channel Processor Unit (CH-PR) (DATS Not DLP-511
Required) :
14. If Required, Conduct Echo Canceler Test (Must Be Performed for Each End of Trunk) DLP-515
15. Terminate Communication with Far-End Office
16. Update Office Records

NTP-005
Page 1of 1AT&T 356-024-510
Issue 1
ESTABLISH DIGROUP IN 48-CHANNEL MODULE
DO ITEMS BELOW IN ORDER LISTED. . . . . . . . . . . . . . . . . FOR DETAILS, GO TO
1. Warning The LT-2 Circuit Packs Contain Static-Sensitive Components
Which Could Be Damaged by Electro-Static Discharge. Before Unpacking
or Handling Circuit Packs, Refer to Special Handling Preca utions in Section
032-173-301.
2. Connect Wrist Strap Between Wrist and LT-2 Bay DLP-502
3. Install Basic Digroup Circuit Packs DLP-503
4. Install Fuse(s) in 39C Fuse Block for Digroup Being Installed DLP-505
.5. From Office Records, Determine if Signaling or Echo Canceler Options Are Required
(One or Both Options May Be Installed in Digroup Located in 48-Channel Module)
6. If Required, Install Signaling Circuit Packs (Two per Digroup) DLP-512
7. If Required, Install Echo Canceler Circuit Pack(s) (One per Group) DLP-51G
8. Warning: Do Not Install More Than One CA UPer Bay. Each Bay Requires
One Control and Access Unit (CA U) Mounted in CA UPosition of One and
Only One Shelf
If Not Already Installed, Install Control and Access Unit DLP-508
9. Install Power Converter Unit(s) DLP-507
10. If Not Already Installed, Install SL106 Alarm Unit DLP-506
11. If Not Already Initialized, Initialize Control and Access Unit DLP-509
12. If Parameter Data Is To Be Entered from Remote Office, Update Office Records to
Reflect Work Completed and Ignore Remaining Items in This Procedure
13. Enter Channel Signaling, Via-Net-Loss (ICL), and Echo Canceler Parameters DLP-51O
14. Establish Communication with Office at Far End of Analog Facility and Request
Assistance in Performing Item 15
15. Alia Receive Gain (Do Aor B, not Both)
A. LT-2 Equipped with SL114 Channel Processor Unit (CH-PR) (Using DATS L1,LB DLP-521
or L1 MOD A}
B. LT-2 Equipped with SL174 Channel Processor Unit (CH-PR) (DATS Not DLP-511
RequiredE
16. If Required, Conduct Echo Canceler Test (Must Be Performed for Each End of Trunk) DLP-515
17. Terminate Communication with Far-End Office
18. Update Office Records

NTP-006
Pogelofl
ADD SIGNALING OPTION TO DIGROUP
DO ITEMS BELOW IN ORDER LISTED. ................ FOR DETAILS, GO TO
1. Warning: The LT-2 Circuit Packs Contain Static-Sensitive Components
Which Could Be Damaged by E]ectro-Static Discharge. Before Unpacking
or Handling Circuit Packs, Refer to Special Handling Precautions in Section
032-173-301.
2. Connect Wrist Strap Between Wrist and LT-2 Bay DLP-502
3. Turn Off Power Unit for Digroup Being Modified
4. Install Signaling Circuit Packs (Two per Digroup) DLP-512
5. Turn On Power Unit for Digroup Being Modified
6. Update Office Records
.

NTP-007
Page lefl AT&T 356-024-510
hsue 1
ADD ECHO CANCELER TO
DO ITEMS BELOW IN ORDER LISTED. . . . . . . . . . . . . . . . . FOR DETAILS, GO TO
1. Warning The LT-2 Circuit Packs Contain Static-Sensitive Components
Which Could Be Damaged by Electro-Static Discharge. Before Unpacking
or Handling Circuit Packs, Refer to Special Handling Precautions in Section
032-173-301.
2. Connect Wrist Strap Between Wrist and LT-2 Bay DLP-502
3. Turn Off Power Unit for Digroup Being Modified
4. Install Echo Canceler Circuit Pack(s) (One per Group) DLP-513
5. If Installing Echo Cancelers in 48-Channel Module, Install Second Power Converter DLP-507
Unit, If Not Already Installed
“6. If Installing Echo Cancelers in 48-Channel Module, Install Second Fuse in 39C Fuse DLP-505
Block -,
7. If Installing Echo Cancelers in 48-Channel Module, Turn On Power Unit for Echo
Cancelers (PCU 1or PCU 3) Before Turning on Power Unit for Digroup Circuit Packs
(PCU 2or PCU 4)
8. Turn On Power Unit for Digroup Being Modified
9. Conduct Echo Canceler Test (Must Be Performed for Each End of Trunk) DLP-515
10. Update Office Records

AT&T 354-034-510
Issue 1TAD-1 00
Page 1of 1
MAINTENANCE PHILOSOPHY
OVERAU STRUCTURE
All procedures are designed to be used on aprogrammed-logic basis; therefore, any attempt to use
procedures by other than the prescribed method of entry may cause erroneous test results and operational
troubles.
ALARMS
In the event of trouble, all alarms should be cleared first. If trouble remains, it should be cleared in
accordance with indicated procedures.
When major and minor alarms occur simultaneously, the major alarm should be cleared first.
Some panel lamps that light during alarm conditions may not be significant in clearing trouble; thus, they
may not be listed in the trouble-locating procedures.
TROUBLE-LOCATIONSEQUENCE
Trouble-location procedures are structured so that applicable adjustments are made first. If necessary, all
circuit packs that may be causing trouble are replaced (one at atime). If this does not clear the trouble,
associated wiring and components (external to circuit packs) are checked.
Aid in locating trouble in wiring and associated equipment not covered in this document may be obtained
by use of SDS, EDs, etc., as provided locally.
CIRCUIT PACKS
If acircuit pack is replaced with aspare in an attempt to correct atrouble, and the spare does not correct
the trouble, the original circuit pack should be re-inserted.
If acircuit pack is replaced with aspare and the spare does correct the trouble, all tests that preceded the
test in which the replacement was made should be repeated for any equipment that may be affected by the
replacement unit.
If acircuit pack must be replaced with aspare, when the original circuit pack has been conditioned and
adjusted according to prior procedures, those conditioning and adjusting procedures must be performed on
the spare circuit pack also before continuing with the procedure requiring circuit pack replacement.
Defective circuit packs will normally be sent to aservice center for repair.
TESTEQUIPMENT
All tests are based on the assumption that the required test equipment is functioning properly.

TAP-101
Page 1of 9AT&7 356-024-510
Issue 1
1.
2.
3.
4.
CLEAR MAJOR ALARM
(FIG. 1) At LT-2 terminal keyboard, enter following message using bay number of bay under test.
DS:bayA;CARRIAGE RETURN
Response: BAY =fffHfWf (fa) VER V.V
DIGROUP s,d
ALARM CONDITIONS:
(description of alarm)
DCFA COUNTER 000 (0000 HEX)
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V=generic version of firmware
s,d =shelf number, digroup number
DS:17:A; <CARRIAGE RETURN>
Where: 17 =2-character frame (or bay) address
A=Display parameter to give alarm status
<CARRIAGE RETURN> =Executes command line
FIG. 1-Example of DS Cammand line Input
The LT-2 display terminal will display trouble message. Did you receive one of these messages?
If OUT OF LOCK, then do Step 4.
If SIG CON OUT OF SYNC, then do Step 12.
If LOOP TONE FAILEDIN GRP X(WHERE X=1OR 2), then do Step 18.
If DCFA -REDALM, then do Step 23.
If DCFA -YEUOW AMA, then do Step 34.
If DCFA-RED,YELLOWALM, then do Step 49.
If NONE OF THESE,then continue to Step 3.
Which of these messages did you receive?
If BASIC CKT PKS NOT PRES,then do Step 58.
If TEMP EXCEEDSltMITS, then do Step 64.
If BOTH FANS FAILED,then do Step 72.
Check position of synchronization switches on SL119 Clock Unit.
Reference DLP-518

AT&r 356-024-510
Issue 1TAP- 101
Page 2of 9
5.
6.
7.
8.
9.
10.
11.
12.
13.
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 6.
Replace SL119 Clock Unit.
Reference DLP-519
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 8.
Replace SL115 T-Interface Unit.
Reference DLP-519
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 10.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
sheIf ), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
Caution: Service could be interrupted when RS-CP command is executed.
(FIG. 2) At LT-2 keyboard terminal, enter following message using bay, shelf, and digroup numbers
of digroup under te~t. RS-CP:bay,shelf,digroupFUU;CARRIAGE RETURN
Response: BAY =ffffWHf (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 14.
RS-CP:17,3,4:FULL; <CARRIAGE RETURN>
Where 17 =2-character frame (or bay) address
3=Shelf number
4=Digroup number
FULL =Parameter to cause full restart
<CARRIAGE RETURN> =Executes command line
FIG. 2- Example of RS-CPCommand line Input

TAP-1 01
Pago 3of 9AT&T 356-024-510
Issue 1
14.
15.
16.
17.
18.
19.
20.
21.
22.
Replace SL117 Signaling Control Unit.
Reference DIP-S19
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 16.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
shelf), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
(FIG. 3) At LT-2 keyboard terminal, enter following message using bay, shelf, and digroup numbers
of digroup under test. DG:bay,sheIf,digrou~CARRIAGE RETURN
Response BAY =ffffffffff (fa) VER V.V
DIGROUP S,d
Diagnostic Message
EXECUTION COMPLETE (M23)
Where f=2-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
s,d =shelf number, digroup number
Diagnostic Message (Dxx) =One of 22 diagnostic messages listed
in back of LT-2 USER GUIDE. This message will tell you
probable cause of trouble.
Follow instructions given in diagnostic message.
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 21.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
shelf ), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHISPROCEDURE.
DG:17,3,4;<CARRIAGE RETURN>
Where 17= 2-character frame (or bay) address
3=Shelf number
4=Dlgroup number
<CARRIAGE RETURN> =Executes command line
FIG. 3- Example of DG command line Input

AT&T 35-4-510 TAP-101
Issue 1Page 40f9
23. (FIG. 4) Loop digroup on itself by doing the following. At LT-2 keyboard terminal, enter following
message using bay, shelf, and digroup numbers of digroup under test. CN-LD:bay,shelf, digroup;
CARRIAGE RETURN
Response: BAY =HffWfff (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
24. Wait for 20 seconds.
25. Did red ALM stop?
If YES, then continue to Step 26.
If NO, then do Step 29.
CN-LD:17,3,4; <CARRIAGE RETURN>
Where 17= 2-character frame (or bay) address
3=Shelf number
4=Digroup number
<CARRIAGE RETURN> =Executes command line
FIG. 4- Example of CN-LD Cammand line Input
26. (FIG. 5) Remove digroup loop by entering following message using bay, shelf, and digroup numbers
of digroup under test. DC-1.D:bay,shelf,digroup;CARRIAGE RETURN
Response: BAY =ffWffHf (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
DC-LD:17,3,4:<CARRIAGE RETURN>
Where 17= 2-character frame (or bay) address
3=Shelf number
4=Digroup number
<CARRIAGE RETURN> =Executes command line
FIG. 5- Example of DGLD Cammand line Input

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TAP-1 O] AT&T 356-024-510
Page 5of 9Issue 1
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
Test indicates SL115 T-Interface Unit is working properly. Check for trouble either at far-end or
cable between near- and far-end.
STOP. YOU HAVE COMPLETEOTHIS PROCEDURE.
(FIG. 5) Remove digroup loop by entering following message using bay, shelf, and digroup numbers
of digroup under test. DC-lD:bay,shelf,digroup;CARRIAGE RETURN
Response BAY = ~ (fo) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Replace SL115 T-Interface Unit.
Reference DLP-519
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEOTHIS PROCEDURE.
If NO, then continue to Step 32.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel’ --
shelf), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEOTHIS PROCEDURE.
(FIG. 4) Loop digroup on itself by entering following message using bay, shelf, and digroup numbers
of digroup under test. CN-lD:bay,sheif,digroup; CARRIAGE RETURN
Response BAY =fffWHff (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Wait for 20 seconds.
Did yellow ALM stop?
If YES, then continue to Step 37.
If NO, then do Step 40.
(FIG. 5) Remove digroup loop by entering following message using bay, shelf, and digroup numbers
of digroup under test. DC-lD:bay,shelf, digroup;CARRIAGE RETURN
Response BAY =WffHfff (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Test indicates SL115 T-Interface Unit is working properly. Check for trouble either at far-end or
cable between near- and far-end.

AT&r 356-024-510
Issue 1TAP-101
Page 6of 9
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
(FIG. 5) Remove digroup loop by entering following message using bay, shelf, and digroup numbers
of digroup under test. DC-lD:bay,shelf,digroup;CARRIAGE RETURN
Response: BAY = ~ (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Caution: Service could be interrupted when RS-CP command is executed.
(FIG. 2) At LT-2 keyboard terminal, enter following message using bay, shelf, and digroup numbers
of digroup under test. RS-CP:bay,shelf, digroup:FUU;CARRIAGE RETURN
Response BAY =fffHfWf (fa) VER V.V
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V=generic version of firmware
Has trouble been cleared?
If YES,then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 43.
Check equalizer switches on SL115 T-Interface Unit and ensure that one and only one switch is in
down position (bottom of rocker in).
Reference DLP-517
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 45.
Replace SL-115 T-Interface Unit.
Reference: DLP-519
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 47.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
shelf), or (SD-54502-01, 48-channel shelf).
S1OP. YOU HAVE COMPLETEDTHIS PROCEDURE.

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TAP-101
Paga 7of 9AT&T 356-024-510
Issuo 1
49.
50.
51.
52.
.53.
54.
5!5.
56.
57.
58.
(FIG. 4) Loop digroup on itself by entering following message using bay, shelf, and digroup numbers
of digroup under test. CN-lD:bay,sheif, digrau~CARR.IAGE RETURN
Response BAY =fffWf#f (fa) VER V.V
EXECUTION COMPLETE (M22) -
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
Wait for 20 seconds.
(FIG. 5) Remove digroup loop by entering following message using bay, shelf, and digroup numbers
of digroup under test. DC-1.D:bay,shelf,digroup;CARRIAGE RETURN
Response BAY =fffffHW (fa) VER V.V
EXECUTION
Where f=
Wait for 20 seconds.
Which alarms do you have now?
COMPLETE (M23)
10-character frame identification code
fa =2-character frame address
VER V.V=generic version of firmware
-.
If REDONLY, then do Step 23.
If YEUOW ONLY, then do Step 34.
If BOTH REDAND YELLOW,then continue to Step 54.
Replace SL115 T-Interface Unit.
Reference IMP-519
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 56.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
shelf), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
(FIG. 5) To determine which equipment is present in digroup, enter following message using bay,
shelf, and digroup numbers of digroup under test. DS:bay,shelf,digraup: E;CARRIAGE RETURN
Response BAY =HfffWff (fa) VER V.V
DIGROUP s,d
EQUIPMENT:
(Description of Equipment in Digroup)
EXECUTION COMPLETE (M23)
Where f=10-character frame identification code
fa =2-character frame address
VER V.V =generic version of firmware
s,d =shelf number, digroup number

AT&T 356-024-510
Issue 1TAP- 101
Page 8of 9
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
Is any equipment missing from digroup?
If YES, then continue to Step 60.
If NO, then do Step 62.
Install missing equipment.
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 62.
Check wiring in shelf and/or bay (SD-54500-01 application schematic),
shelf), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
Ensure all shelf covers (front and rear) are properly installed.
Ensure bottom air inlet grill for fans is not blocked.
Ensure fan air filter is clean (replace if necessary).
Reference DLP-526
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 68.
(SD-54501-01, 96-channel
Replace each SL113 Translation Unit in alarming shelf (one at atime), stopping after each
replacement to see if trouble is cleared.
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 70.
Check wiring in shelf and/or bay (SD-54500-01 application schematic), (SD-54501-01, 96-channel
shelf), or (SD-54502-01, 48-channel shelf).
STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
Ensure bottom air inlet grill for fans is not blocked.
Ensure fan air filter is clean (replace if necessary).
Reference DLP-526
Has trouble been cleared?
If YES, then STOP. YOU HAVE COMPLETEDTHIS PROCEDURE.
If NO, then continue to Step 75.