Northern Telecom DMS-1 User guide

NORTHERN
TELECOM PRACTICES
SECTION
363-2011-300
Issued: 78
11
10
Standard N
DMS-1* DIGITAL MULTIPLEX SYSTEM
SYSTEM OPERATION
I.
2.
3.
4.
CONTENTS
PAGE
GENERAL
.•••••••••••••••••••••••
I
ALARMS
•••.•••••••••••••••••••••
I
Charts
1.
RCT
Alarm Display Operation .... 3
2.
CCT
Alarm Display Operation .
...
4
CONTROLS
•••••••••••••••••••••••
s
Charts
3. Power Supply Reset . • . • . • • • • • • • . s
4. System Controller Restart
.••.••••.
6
s.
Protection Switching, Bypass,
and Loopback . •• . • . • . • . • . • • . • . • 6
6. Traffic Measurement . • . • . • . • • • • . • 10
7.
Priority/Dedicated Selection
.••.••.
II
TEST ACCESS
••••••••••••••••••••
12
Charts
8. QPP425 System Test Circuit Pack
Calibration and Tests . • • • • • • • • . • . 23
9. QPP424 Line Test -Office
Circuit Pack Operation . • . • • • • • • • . 28
10. QPP450 Test Control Circuit
Pack Tests . • • . • . • • • • • . • • • • • • • .
31
11. QPP448 Test Access Circuit
Pack Operation . • • • . • . • • . . • • • • • . 34
S.
ORDER
WIRE
• • • • • • • • • • • • • • • • • • • • 37
Charts
12. Initiating a Call
at
an
RCT
. • . . • • . 37
13. Initiating a Call from a Repeater
Site . • . . . • • . • • • • • • • • • • • • • • • • • . 38
14. Answering a Call
at
the
CCT
.••..
39
6. EMERGENCY
POWER
• • • • • • • • • • • • • 40
Charts
15. Connecting and Removing
an
Emergency Generator
at
an
RCT
40
7.
DIGITAL
LINE
FAULT
LOCATION • • • • • • • • • • • • • • • • • • • • • • •
41
• DMS-1 is a trademark
of
Northern Telecom Limited
I.
GENERAL
1.01 This section outlines procedures required for
the operation
of
the
DMS-1 Digital Multiplex
System. The information contained in this section is
supplementary
to
the descriptive
and
maintenance
practices.
1.02 Reason
for
Reissue:
to
add new
and
revised
information.
1.03 The DMS-1 system normally operates
automatically. The monitor and alarm circuits
within the system detect
and
indicate
any
degradation
in performance
or
any equipment failure. When the
system is functioning correctly and all input signals
are
present, there are
no
visual
or
audible alarms.
When the system detects trouble, office alarms,
remote alarms, and equipment alarms are activated.
1.04 The indicators
on
the faceplates
of
the alarm
circuit packs (Fig. 1
and
2) are used as a
f~rst
step in fault location. The functions
of
these
indicators are described in 363-2011-500.
1.05 Controls
on
the faceplates are used for
adjustments, system testing,
and
fault
location.
2. ALARMS
2.01 Most
RCT
alarms are displayed
on
the
QPP420 ALM
REM
circuit
p_ack
(Fig. 1).
The Remote Concentrator Terminal (RCT) alarms
are
also transmitted
to
the Control Concentrator
Terminal (CCT) and displayed
on
the QPP421
ALARM
OFFICE
circuit pack together with
CCT
alarms. In addition
to
the centralized alarm display,
failure
of
the initial
or
the backup circuit pack, where
optional backup circuit packs are installed, is
indicated by a light
on
the QPP431 SYS
CONT
and
QPP426
RING
GEN.
®Northern Telecom Limited 1977
Printedin
Canada
Page 1
41
Pages

SECTION 363-2011-300
I
I
ALM
REM
LP
I
"'
•
DFA
.
DFB
.
LFA .
LFS
.
lt
FP
.
L
PF
.
RMJ
.
RMN
.
CPF
.
AC
.
SAT
.
TEM
.
DOOR
.
i
FUSE
.
•
•
•
•
ON
OFf
Fig. 1 - QPP420A ALM REM Circuit Pack
Page 2
I
ALARM
OFFICE
•
II'ITCE
~·
ALM
i
l .
OCP
FAIL - A
l .
DCP
FA
IL-
8
li
NE
FA
ll-
A
4.
LJN£
fAll-8
S.
liHE
fA
IL-
P
6. 8YPASS
DP
7. LP8K
DP
S. T
BAT
9.
L1NE
PW;
lO
.
RINC
CEN
ll
.
COM
PWR
u•
•c
FAtL
ll
.8AT
fAll
14
.
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TE"P
lS .
DPEN
OODR
16 . RI
NC
OIST F
11.
HUL
T
LOC
18.
ll
OET
fA
IL
19
.
SYS
CO
NT
lO
•
H.
n •
23
•
ER
QPP421A
Fig.
2 -
QPP421 ALARM OFFICE Circuit Pack

SECTION 363-2011-300
CHART I
RCT ALARM DISPLAY OPERATION
This chart describes the operation
of
the LP TST button and display ON/OFF switch on the QPP420 ALM
REM circuit pack at the RCT.
STEP PROCEDURE
1 Switch the display ON/OFF switch to the ON position.
Requirement:
If
there are any alarms, the corresponding indicator shall light.
2 Press and hold the LP TST button on the QPP420 circuit pack.
Requirement:
All
indicators shall light
while
the button
is
pressed.
3 Release the LP TST button.
4 Switch the ON/OFF switch to OFF.
Requirement: No alarm indications on QPP420.
If
any of the requirements are not met, replace the QPP420 circuit pack.
Page 3

SECTION 363-2011-300
CHART 2
CCT ALARM DISPLAY OPERATION
This chart describes the operation
of
the controls on the QPP421 ALARM OFFICE circuit pack at the CCT.
STEP PROCEDURE
A.
ACO
Operation
When an office alarm
is
caused by the DMS-1 system, press the ACO button (Fig.
2).
Requirement
1:
The audible office alarm must stop ringing.
Requirement 2: The visual office alarm must
go
out.
Requirement
3:
The bay alarm light must
go
out.
Requirement
4:
The alarm indication on the ALARM OFFICE display must remain lit.
B.
Display Selection
Note:
When an office alarm
is
caused by the DMS-1 system, one
of
the four
RCT
lamps
or the CCT lamp on the QPP421 circuit pack must light.
2 Press and hold the LP TEST button.
Requirement:
All
indicators shall light
while
the button
is
pressed.
If
the requirement
is
not met, replace the QPP421 circuit pack.
3 Release the LP TEST button.
Requirement:
All
indicators shall
go
out.
4 Switch the MTCE ALM switch on the QPP421 to the ALM position.
5
Tum the RCT/CCT selector until the pointer
is
pointing to the indicator which is lit.
Requirement: One or more indicators on the QPP421 circuit pack must light.
6
If
the FAULT LOC lamp
is
lit, switch the MTCE ALM switch to the MTCE position and the
RCT/CCT selector to the indicator which
is
then lit.
Page 4
Requirement: LED indicating the faults must light.
Note: Refer to 363-2011-500, Fig. 1 for interpretation
of
the alarm and maintenance
lights.

SECTION 363-2011-300
3. CONTROLS
CHART 3
POWER SUPPLY RESET
This chart describes the steps to be carried out to restore the QPC85 5/12-V converter and QPP439line power
converter to operation after replacement or repair
of a system fault causing an over-current condition.
STEP PROCEDURE
1 On the
fuse panel check the 48-V supply fuse for the converter.
Requirement 1: The fuse current rating must match the value indicated on the fuse panel,
and the colored indicator on the
fuse must match the colored insert in the fuse holder.
Requirement 2: The fuse indicator must not protrude from the face of the fuse.
2 Check the QPP420 at the RCT or the QPP421 at the CCT as applicable.
Requirement 1: The CPF (at RCT) or COM PWR (at CCT), or the LPF (at RCT) or
PWR (at CCT) indicator must
be lit.
Requirement 2: The FAIL indicator on the line power converter must light if the line
power converter has failed.
3 Press the RESET button on the faceplate of the power converter.
Requirement: The indicators on the alarm display and the FAIL indicator on the line
power converter
(if applicable) must go out.
If the requirement is not met or a fuse blows, refer to 363-2011-500, Flowchart 6 (for a line
power converter) or Flowchart 8 (for a common power converter), for locating and correcting
the fault.
4 Release the RESET button.
Page 5

SECTION 363-2011-300
CHART 4
SYSTEM CONTROLLER RESTART
This chart describes the steps to be carried out to start a QPP431
SYS CONT initially or to restart it after
maintenance operations.
STEP PROCEDURE
Check the FAIL indicator on the QPP431 faceplate.
Requirement: The FAIL indicator must be lit.
2 Press both the RESTART and RESTART ARM buttons simultaneously, and then release both
buttons.
Requirement: The FAIL indicator must go out.
If the requirement is not met, refer to 363-2011-500 Flowchart 15 for locating and correcting the
fault.
CHART 5
PROTECTION SWITCHING, BYPASS, AND LOOPBACK
This chart describes the steps to
be carried out to initiate manually a protection switch, an RCT bypass, or a
digital
line loopback. The functions of the controls and indicators on the QPP429 PROT SW OFF circuit pack
and QPP499 1-for-n PROT SW
OFF circuit pack are described in Table A.
Note:
All manual switches on the QPP429 and QPP499 are toggle types with detents to lock them into
position. To change the position
of a switch:
(1) pull out on the switch toggle,
(2) move the toggle to the
new position,
(3) release the toggle, allowing it to
fall into the detent at the new position.
STEP PROCEDURE
A. Protection Switching
Page 6
On the QPP429 or QPP499 at the CCT, switch the ARM switch to the ON (up) position.
Requirement: The ARM indicator must light.
2 To transfer traffic from working digital
line A (or B) to the protection line, switch the PS A (or B)
switch to the ON (up) position.
Requirement 1: The PS A (or B) indicator must light.
Requirement 2: On the QPP429, the PS OP counter must increase by one count.
Chart Continued

SECTION 363-2011-300
CHART S Continued
PROTECTION SWITCHING, BYPASS, AND LOOPBACK
STEP PROCEDURE
3 To release the protection switches and restore traffic to the digital line A (or
B),
switch the
PS
A
(or
B)
switch to the RELEASE/INHIBIT (down) position.
Requirement: The PS A (or
B)
indicator must
go
out.
4 To inhibit automatic operation
of
the protection switch, switch the PS A (or
B)
switch to the
RELEASE/INHIBIT position.
5 To allow automatic operation
of
the protection switch, switch the PS A (or
B)
switch to the
NEUTRAL (center) position.
6 When testing
is
complete, release the ARM switch.
Requirement: The ARM indicator must go out.
Note:
In
systems equipped with protection switching circuit packs, but with no protection
line
available, leave the PSA and
PSB
switches in the INHIBIT (down) position, and ARM
switch
in
the
ON
(up) position.
B.
RCT
Bypass
Caution: Bypassing an
RCT
denies service to subscribers on the bypassed
RCT.
7 On the QPP429 or QPP499, set the ARM switch to the ON (up) position.
Requirement: The ARM indicator must light.
8 To bypass
RCTl
(or
2,
3,
4) switch the BPI (or
2,
3,
4) switch
to
the
ON
(up) position.
Requirement 1: The office major alarm must operate.
Requirement 2: The BYPASS OP and
RCTl
(or
2,
3, or 4) indicators on the QPP421
circuit pack must light.
9 To release the bypass relays at the bypassed
RCTl
(or
2,
3,
4) switch the BPI (or
2,
3, 4) switch
to the RELEASE/INHIBIT (down) position.
Requirement 1: The office major alarm must be turned
ofT
(if
not canceled previously by
means of the ACO switch).
Requirement 2: The BYPASS OP and
RCTl
(or
2,
3, or 4) indicators on the QPP421
circuit pack must
go
out.
Note: An RCT
will
bypass automatically
if
both +5 V power supplies
fail.
If
this occurs,
set the appropriate BYPASS switch and the ARM switch to the
ON
(up) position before
repairing the RCT. After repair is completed, restore service by setting the BYPASS switch
to the RELEASE (down) position.
10
When testing
is
completed, release the ARM switch.
Requirement: The ARM indicator must
go
out.
Chart Continued
Page 7

SECTION 363-2011-300
CHART 5 Continued
PROTECTION SWITCHING, BYPASS, AND LOOPBACK
STEP
PROCEDURE
C. Loopback
Caution: Looping back the digital lines
at an RCT denies service to the subscribers on all
higher numbered
RCT (e.g., loopback at RCT1 denies service to subscribers on RCT2 and
RCTJ).
11 On the QPP429 or QPP499, set the ARM switch to the ON (up) position.
Requirement: The ARM indicator must light.
12 To loopback one digital line (in a single-digroup system) or both digital lines (in a dual-digroup
system) at RCT1 (2
or 3), switch the LP1 (2 or 3) switch on the ON (up) position.
Requirement 1: The office major alarm must operate.
Requirement 2: The LPBK OP and RCT2 (3 or 4) indicators on the QPP421 circuit pack
must light.
13 To release the loopback relays at RCT1 (2 or 3) switch the LP1 (2 or 3) switch to the
RELEASE/INHIBIT (down) position.
Requirement 1: The office major alarm must be turned off (if not canceled previously by
means
of the ACO switch).
Requirement 2: The LPBK OP and RCT2 (3 or 4) indicators on the QPP421 circuit pack
must go out.
14 To allow automatic operation of the loopback relays at RCT1 (2 or 3) switch the LP1 (2 or 3)
switch to the NEUTRAL (center) position.
15 When testing is completed, release the ARM switch.
Requirement: The ARM indicator must go out.
Page 8

SECTION 363-2011-300
TABLE A
PROTECTION SWITCHING, BYPASS, AND LOOPBACK CONTROLS
AND INDICATORS ON QPP429 AND QPP499
DESIGNATION TYPE FUNCTION
A. Controls
ARM 2-position, toggle ON - allows operations initiated by the
switch; locked other manual switches on the QPP429 or
detents QPP499 to be carried out.
OFF- prevents operations initiated by the
other manual switches on the QPP429 or
QPP499 to be carried out.
PS A 3-position, toggle ON -initiates a protection switch from
and switches; locked the working
line (A or B) to the protection
PS B detents
line at the CCT and at all RCT.
NEUTRAL -
allows automatic operation of
the protection switches.
RELEASE/INHIBIT -restores traffic to
the working
line (A or B), if the protection
switch has previously been operated; or
inhibits automatic operation,
if no protec-
tion switch is operated.
BPI 3-position toggle ON -initiates operation
of the bypass
BP2 switches; locked relays at the selected RCT.
BP3 detents
BP4 NEUTRAL -equivalent to RELEASE.
RELEASE -releases the bypass relays at
the selected RCT
if previously operated.
LPI 3-position toggle ON -initiates operation
of the loopback
LP2 switches; locked relays at the selected RCT.
LP3 detents NEUTRAL -allows automatic operation
of the loopback relays.
RELEASE/INHIBIT -releases the
loopback relays at the selected RCT,
if
previously operated; or inhibits automatic
operation
of the loopback relays.
LAMP TST pushbutton Lights the ARM, PS A, and PS B
indicators; and, on QPP429 only, causes
the
PS OPS display to indicate 888.
Table Continued
Page9

SECTION 363-2011-300
TABLE A Continued
PROTECTION SWITCHING, BYPASS,
AND
LOOPBACK CONTROLS
AND
INDICATORS
ON
QPP429 AND QPP499
DESIGNATION TYPE FUNCTION
B.
Indicators
ARM
PS A
PS B
PS DPS
BUSY
Red LED Indicates that the ARM switch
is
turned
on.
Red LED Indicates that traffic on working line A
has been switched onto the protection line.
Red LED Indicates that traffic on working line B
has been switched onto the protection line.
3-digit LED display Indicates the number
of
protection switch
operations that have occurred.
Red LED On QPP499 only; indicates that the
protection line
is
in use by another DMS-1
system.
CHART
6
TRAFFIC MEASUREMENT
There is only one control on the QPP434 TRAFFIC circuit pack. It
is
used to reset the high-hourly-CCS counter
to zero.
STEP PROCEDURE
1 Press the RST button on the faceplate
of
the QPP434 circuit pack.
Requirement: The reading on the high-hourly-CCS counter shall change to all zeros.
2 Release the RST button.
Page 10

CHART
7
PRIORITY/DEDICATED SELECTION
SECTION 363-2011-300
This chart describes how to set the switches on the front
of
the QPP411
PRIOR/DED
circuit pack for priority
or
dedicated operation.
STEP
PROCEDURE
1 Determine the line number for which priority
or
dedicated service is
to
be provided.
2 Locate the line number on the designation strip on the front
of
the line shelf(Fig. 3). Verify that
the circuit pack
at
that location is a QPP411 PRIOR/DED.
32-3S
36-39
40-43
44-47
I
I I
~
PRIOR/
PRIOR/ PRIOR/ PRIOR/
OED
r- r-
PO PO
~0
PO
"'
~@
UNE
0
I@
UNE-o
@
UNEO
@
UNEQ
I@
LINE I
f@
LINE
l @
LINE
i @
UNE
I
@
LINE
2
@:
UNE
2
@LINE
2
@
LINE2
@LINE
3
@LINE
3
@LINE
J
@LINE
3
LINE
0
LINE 0 LlHE 0
LINE
0
LINE
I
LINE
1
LINE
J
LINE
1
LINE 2
LINE
2
LINE 2
LINE 3 LINE 3
LINE
3
LINE 3
QPNll
QPP.fl1
1 1
Fig. 3 - Line Circuit Pack Locations
3 Set the corresponding line switch on the faceplate
of
the QPP411 circuit pack
to
either P
or
D
depending on the type
of
service desired.
Example 1:
Dedicated channel operation is desired on line 33.
On the QPP411 circuit pack located
at
line-group position 32-35, set the
LINE
1 switch to
the
'D'
position.
Example 2:
Priority operation is desired on line 38.
On
the QPP411 circuit pack located
at
line-group position 36-39, set the
LINE
2 switch to
the
'P'
position.
Page
11

SECTION 363-2011-300
4. TEST ACCESS
4.01 DMS-1 system performance can be checked
from the
CCT using either:
(a) a QPP425 SYSTEM TEST circuit pack,
Fig. 4(a); the functions
of its controls,
indicators, and jacks are listed
in Table B;
calibration and operation are described
in Chart 8.
(b) a QPP450 TEST CONTROL circuit pack,
Fig. 4(c); the functions
of its controls and
indicators are listed
in TableD; operation is
described
in Chart 10.
4.02 Subscriber lines connected to the RCT can be
tested from the CCT by one
of two systems,
depending on the type
of test circuits installed at the
CCT and RCT:
(a) through the DMS-1 system using QPP423
LINE TEST REMOTE circuit packs at the
RCT, and a QPP424 LINE TEST OFFICE,
Fig. 4(b), at the CCT; either a QPP425
or a
QPP450
is used with the QPP424 at the CCT to
control the tests and to display the test results; or
(b) on a separate metallic test line bypassing the
digital circuits
of the DMS-1 between the CCT
and the RCT terminals to which the subscriber
Page
12
lines are connected; this system requires QPP447
TEST ACCESS REMOTE circuit packs and
REMOTE BYPASS assemblies (ED7208-32,G4)
at the RCT, and QPP448 TEST ACCESS
OFFICE circuit packs and OFFICE BYPASS
assemblies (ED7208-32,G3) at the
CCT; a
QPP425 or a QPP450
is used with the QPP448 at
the
CCT for local manual control of the test
access; a separate test instrument is required at the
CCT; this system can also be operated remotely
through an extension to the test center.
4.03 Functions
of the controls, indicators, and
jacks on the test circuit packs, and operation
of the circuit packs are described in the tables and
charts as follows:
(a) QPP424:
in Table C and Chart 9;
(b) QPP447 and QPP448: in Table E and
Chart 11;
(c) QPP423: there are no operating controls,
indicators, or jacks on the QPP423 faceplate.
4.04 Remote operation
of the Subscriber Line Test
Extension (SLTE) from a test center depends
on the facilities at the test center. Refer
to the
applicable manuals and procedures for the test center
for operating details.

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(A)
(B)
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(C) (D)
Fig. 4 -
(a)
(b)
(c)
(d)
Circuit Pack
QPP423
Line Test-
Remote
(Not
Shown)
OPP424
Line Test-Office
OPP425
System
Te
st
OPP447
Test
Access-
Remote
(Not
Shown)
OPP448
Test Acce
ss
-
Office
QPP450
T
est
Control
QPP424 Line Test Office
QPP425 System Test
QPP448 Test Access Office
QPP450 Test Control
SECTION 363-2011-300
Function
Connects
to
the
I
ine
to
be
tested,
carries
out
the
tests
and
transmits
test
results
back
to
the
OPP424
-Selec
ts
the
test,
indicates
the
test
results.
-- Indicates
the
s
tatus
of
the
QPP423
and
the
test
condition
-
Selects
the
I
ine
to
be
tested
-Indicates
if
the
line
is
busy
or
if
another
line
on
the
line shelf
is
ringing.
- Receives
control
data
from
OPP431
at
CCT.
-Drives
remote
bypass
assemb
li
es
(mounted
behind
each RCT shelf).
--
Drives 4
faceplate
indicators.
-Provides
interface
between
the
QPP431
and
office
bypass assemblies
(mounted
behind
each CCT
she
lf) .
-Provides 4
faceplate
switches
and
24
option
selectors
to
contro
l
test
access
operation.
-Drives 5
faceplate
indicators
.
-
Same
as
OPP425
; plus,
-
Di
splays local link
status
.
-Provides
permanent
signal release
(P
SIG
RLS)
control
and
status
display.
Page
13

SECTION 363-2011-300
TABLE B
QPP425 SYSTEM TEST CIRCUIT
PACK-
CONTROLS, INDICATORS, AND JACKS
DESIGNATION TYPE FUNCTION
A.
Controls
LINE selector switch Thumbwheel selector switch with Selects the
line
to
be
tested (0 through
individually adjustable units, 255). Line numbers above 255 are
tens and hundreds. interpreted as the selected line
minus 256.
CHANNEL selector Thumbwheel selector switch with Selects the channel on digroup A or B
switch individually adjustable units, and
to
which the selected
line
is
to
be
tens plus a digroup A or B assigned.
If
the channel number selected
selector is greater than
23
(i.e., 24 to 29) the
system controller will assign the next
available channel
to
the line.
ON/OFF Pushbutton switch, latching When pushed in (ON position),
indicates
to
the system controller that
the system test
etreuit
pack is in use.
ASSN Pushbutton switch, latching Instructs the system controller to assign
the selected channel
to
the selected line
to provide an end-to-end
vf
connection.
LOOP OFFICE Pushbutton switch, latching (a) Instructs the system controller:
(1)
to
assign the channel indicated on
the CHANNEL selector switch
to
the line number indicated on the
LINE selector switch.
(2)
to
operate the loopback relays on
the
line
and buffer circuit packs.
(b) Causes the system test circuit pack:
(
1)
to convert a
vf
signal from the
internal oscillator (or inserted into
the EXT SCE jack) into
digital
words and to insert the words into
the channel selected on the PCM bit
stream toward the CCT
line
circuits.
Table Continued
Page
14

SECTION 363-2011-300
TABLE B Continued
QPP425 SYSTEM TEST CIRCUIT
PACK-
CONTROLS, INDICATORS,
AND
JACKS
DESIGNATION TYPE FUNCTION
(2)
to extract and convert the digital
words on the channel selected
from the PCM bit stream returning
from the line circuit to a
vf
signal
and detects the
level
or connects the
signal to the EXT DET jack.
(3)
to
rate
the ring detector logic
on e line circuit and light the
HOOK lamp.
LOOP REM Pushbutton switch, latching Same as LOOP OFFICE except:
(1)
The
vf
signal
is
transmitted to the
RCT and returned from the line
circuit loopback.
(2) The
line
circuit hook and ANI
detectors (as applicable) are operated
and indicated by the HOOK and
ANI
lamps.
SELF TEST Pushbutton switch, latching Connects the digital word output
of
the
system test circuit pack
to
the digital
word input for calibration.
LAMP TEST Pushbutton switch, nonlatching Instructs the System Controller
to
light
all
of
the system test lamps.
Table Continued
Page
15

SECTION 363-2011-300
TABLE B Continued
QPP42S SYSTEM TEST CIRCUIT PACK -CONTROLS, INDICATORS, AND JACKS
DESIGNATION TYPE FUNCTION
B.
Indicators
LINE
BUSY
Red LED Indicates that the selected line is
otT-
hook or has ringing voltage on it from
the switching equipment.
CHANNEL BUSY Red LED Indicates that the selected channel is
busy.
SHELF RNG Red LED Indicates that the test being made has
been terminated because the common .
ring/test bus on the line shelf under test
at the RCT
is
required for ringing.
LEVEL
HIGH/
Red LED Indicates that the loopback
vf
signal
is
OK/LO 2
dB
or more higher than nominal
(HIGH),
within, ±
2
dB
of
nominal
(OK), or 2
dB
or more lower than
nominal (LO).
DC SUPV Red LED (1)
In
LOOP REM mode, indicates
HOOK/ANI operation
of
the HOOK and ANI
detectors on the line circuit selected
at the RCT.
(2)
In
LOOP OFFICE mode, the
HOOK lamp indicates correct opera-
tion
of
the ring detector logic.
c.
Jacks
EXT SCE Bantam, tip-ring-sleeve Connects an external vf signal source to
the signal insertion circuits for calibra-
tion
or
loopback testing. Impedance
is
900 ohms, balanced.
EXT DETR Bantam, tip-ring-sleeve Connects an external detector to the
return
vf
signal for calibration or loop-
back testing. Impedance is 900 ohms,
balanced.
D.
A4iustment
GAIN CAL 20-turn screwdriver adjust Adjusts the internal receive amplifier
gain to calibrate the loopback.
TEST CAL 20-turn screwdriver adjust AdJusts the internal detector gain
to
calibrate the
level
test circuits.
Page
16

SECTION 363-2011-300
TABLE C
QPP424 LINE
TEST-OFFICE-
CONTROLS AND INDICATORS
DESIGNATION TYPE FUNCTION
A. Controls
ON/OFF Pushbutton switch When pushed
in
(ON position), it
indicates
to
the system controller that
the Line Test circuits are
in
use.
AUTO/SEL Pushbutton switch, latching When left out (AUTO position), it
causes the QPP423 line test remote
circuit pack
to
measure ac volts,
FEMF
(DC) resistance, and capacitance for the
selected line when the START/STOP
button
is
pressed. When pushed in
(SEL position), it causes test selected
by the VOLTS ac, FEMF de, RES,
CAP buttons to be repeated, and the
display updated at each repetition. The
test sequence
is
started by pressing the
START/STOP button and updated
continuously for 1 minute.
(See
Note.)
AC
VOLTS, Pushbutton switch, latching When pushed in, selects the test to be
FEMF (DC), repeated (AUTO/SEL switch
in
SEL
RES, Interlocked
so
that only one position) and results
to
be
displayed.
CAP can
be
selected at any one time
START/STOP Pushbutton switch, momentary Starts and stops testing as the button
is
pressed.
Table Continued
Page
17

SECTION 363-2011-300
TABLE C Continued
QPP424
LINE TEST-OFFICE- CONTROLS AND INDICATORS
DESIGNATION
B. Indicators
TIP-RING
TIP-GRD
RING-GRD
V AC
V DC
KOHM
J.LF
>RANGE
OVLD
CAL CHK
FAILED
HALTED
TESTING
TYPE
3 digit and sign,
Red
LED
Red LED
Red LED
Red LED
Red LED
Red LED
FUNCTION
Displays the results of the selected test
from tip-to-ring, tip-to-ground and ring-
to-ground.
Indicates the test parameters being
displayed when a test selection button is
depressed.
Indicates that the value being measured
is outside the measurement range of the
line test remote circuit pack,
or that the
results
of the test selected are not
meaningful because
of interference from
a previous value (e.g., de on pair
>9 V
because
of battery crossed to pair
being measured makes resistance
measurements invalid so the
>RANGE/
OVLD indicator lights).
Indicates that the line test remote circuit
pack has failed the self test calibration
check and should be replaced.
Indicates that testing has stopped
because:
( 1) another line on the shelf is being
rung,
(2) START/STOP control button has
been pressed.
Indicates that the tests are being carried
out.
Note: In the auto run mode, results of resistance and capacitance measurements are compensated for the
effects
of FEMF (de). In the selective mode, this is not so and changes in de voltage on the pair since the
preceding auto-run will give errors in results displayed.
Page
18

SECTION 363-2011-300
TABLED
QPP450 TEST CONTROL CIRCUIT
PACK-
CONTROLS AND INDICATORS
DESIGNATION
A.
Controls
LINE selector
CHANNEL selector
ON/OFF
ASGN
LOOP OFFICE
TYPE
Thumbwheel selector switch with
individually adjustable units, tens
and hundreds
Thumbwheel selector switch
with
individually adjustable units and
tens, plus a digroup A or B
selector
Pushbutton switch, latching
Pushbutton switch latching
Pushbutton switch, nonlatching
Table Continued
FUNCTION
Selects the line to be tested (0 through
255). Line numbers above
255
are
interpreted by the system controller as
the selected number minus 256.
Selects the channel or digroup A or B
to which the selected line
is
to be
assigned.
If
the selected channel number
is
greater than 23, the system controller
assigns the next available channel to the
line.
When pushed in (ON), indicates to the
system controller that the circuit pack
is
enabled; an automatic 1-second lamp
test
is
made when the switch
is
frrst
turned ON.
Instructs the system controller to assign
the selected channel to the selected line
to provide an end-to-end
vf
connection;
instructs the system controller to
take-down a permanent-signal-release
condition; instructs the system controller
to take down a local link connection
if
the selected
line
is
on a local link.
(a) Instructs the system controller:
(1) to assign the channel indicated on
the CHANNEL selector to the
line
indicated on the LINE selector,
(2) to operate the loopback relays on
the
line
and buffer circuit packs.
(3) to operate the ring detector logic
on the line circuit and light the
RING lamp.
(b)
Causes the QPP450, as controlled by
the system controller:
(1) to
insert
vf
signal digital words
into the selected channel on the
PCM bit stream toward the
CCT
line
circuits,
Page
19

SECTION 363-2011-300
TABLE D Continued
QPP450 TEST CONTROL CIRCUIT
PACK-
CONTROLS AND INDICATORS
DESIGNATION TYPE FUNCTION
{2)
to extract the digital words from
the selected channel
of
the PCM
bit stream returning from the
line
circuit, and to digitally detect the
level.
LOOP REMOTE Pushbutton switch, nonlatching Same as LOOP OFFICE except:
(a) The
vf
signal
is
transmitted to the
RCT and returned from the line
circuit loopback.
(b)
The
line
circuit hook and ANI
detectors (as applicable) are oper-
ated and indicated by the
HOOK
and
ANI lamps.
SELF TEST Pushbutton switch, nonlatching Connects the digital word output
of
the
QPP450 to the digital word input, for
calibration.
P SIG RLS Pushbutton switch, nonlatching Instructs the system controller to set up
a permanent signal release condition on
the selected line
if
the
line
is busy.
B.
Indicators
LOC LNK Red LED Indicates that the selected line
is
set up
in a local link at the RCT.
UNE
BUSY
Red LED Indicates that the selected line
is
off-
hook or has ringing voltage on it from
the switching machine.
P SIG RLS Red LED Indicates a permanent
signal
release
condition on the selected line.
CHANNEL
BUSY
Red LED Indicates that the selected channel
is
busy.
SHELF RNG Red LED Indicates that the test has been termi-
nated because the common ring/test bus
on the
line
shelf under test
at
the RCT
is
required for ringing.
Table Continued
Page 20