Bell 9508 Operating and installation instructions

..
BELL
SYSTEM
PRACTICES
AT&
TCo
Standard
SECTION
666-600-1
01
Issue
2, December 1977
1.
2.
3.
4.
5.
SWITCHED DIGITAL
OAT
A
SYSTEM
9508
TESTBOARD
(J70176C)
DESCRIPTION AND OPERATION
CONTENTS
PAGE
1.
GENERAL
GENERAL
PHYSICAL
DESCRIPTION
FUNCTIONAL
DESCRIPTION
OPERATION
Originating a Telephone Call
Answering and Terminating a Telephone
Call
Using
the AUD
OFF
Key
Using
the
TEL
ALM
Key
Placing
a CO
Line
on
Hold
Placing
a Station
Line
on
Hold
Conference Call
Multipoint Signaling Unit
Control and
Test
Codes
Dummy and Signal
Plugs
Clock
Circuit
Check
Using
the
TRK
FAIL
ACO Key
Using the
TST
BD
F/PWR
UN
FAIL
ACO
Key
REFERENCES
4
9
17
17
17
18
18
18
18
19
19
19
20
20
20
20
20
1.01
This section contains a physical
and
functional
description
of
the
950B testboard.
1.02
This section is reissued to:
•
Add
information
concerning
the
alarm
indicator panel.
• Add references to
the
921A
data
test
set
(DTS).
• Add references
to
the
71D
and
76D
power
units.
• Make revisions due
to
equipment changes.
Since
this
reissue constitutes a general revision,
arrows ordinarily used to indicate changes have
been omitted.
1.03
The
950B
testboard
(Fig. 1) is located in a
serving
test
center (STC)
and
is used for
testing
the
switched digital
data
system (SDDS)
equipment
at
the
DS-0 (64-kb/s) level. The
950B
testboard may also be used
for
testing
private line
digital
data
system (DDS) equipment.
1.04
The
950B
testboard
contains jacks,
alarm
indicators, remote digital register sender
interface
unit
(DRSIU) jacks, cord reel units, a
clock circuit, a control
and
test
code
generator
(optional), a multipoint signaling unit
(MSU)
(optional),
a digital signaling
test
unit
(DSTU) (optional), a
local maintenance center display (LMCD) referred
to as
trunk
failure display (TFD)
in
SDDS (optional),
and
telephone circuits. A KS-20908 DTS digital
receiver
and
a KS-20909 DTS digital
transmitter
NOTICE
Not for use
or
disclosure outside the
Bell System except under
written
agreement
Printed
in U.S.A. Page 1

SECTION 666-600-1
01
Page
2
STRIP
CORD
REEL
UNITS
DUMMY
TELEPHONE
HANDSET
------l.l
CONTROL
CODE
SWITCH
HEADSET
JACKS
MULTI
POINT
SIGNALING
UNIT
WRITING
SHELF
ALARM
I
NDICATORS
TRUNK
FAILURE
DISPLAY
JACK
PANELS
DRSIU
JACKS
DRSIU
DECAL
DIGITAL
SIGNAL
TEST
UNIT
DATA
RATE
DECAL
CALL
PROGRESS
CODES
DECAL
KS
-20909
DTS
(TRANSMITTER)
CLOCK
SWITCH
TOUCH-TONE
DIAL
TELEPHONE
KEY
ASSEMBLY
---POWER
UNIT
Fig.
1-0verall
View
of
9508
Testboard
NO.I
(OTHER)
POWER
UNIT
N0
. 2
(DSTU)
CIRCUIT
PACKS

are
also mounted in
the
testboard
but
can be
removed for use as portable
test
sets.
Note:
The MSU is used for private line
multipoint system testing only.
1.05 The testboard contains up to 12 key-operated
telephone circuits associated
with
a key
telephone
unit
(KTU) shelf assembly to allow
communication over station line circuits with local
DDS
and
SDDS equipment bays,
and
over
central
office
(CO)
line circuits with
other
STC testboards,
customers,
and
telephone company (telco) employees
in
the
field in order to properly coordinate
any
tests.
1.06
The testboard is equippd with a
TOUCH-TONE®
or
rotary
dial for use
in
conjunction with a
push-to-talk handset. Headset jacks
are
provided
below
the
handset
so
that
a telephone headset can
also be used
in
conjunction with
or
in place of
the
handset.
1.07 The testboard is also provided
with
the
following:
• A buzzer to
alert
the testboard
operator
of
incoming calls.
• A key to disable
the
buzzer.
• A key to place central office line calls on
hold.
• A key to enable the
CO
service
alarm
on
an
incoming call when
the
testboard
is
left
unattended.
• A key to enable the
CO
service
alarm
on a
testboard fuse
or
power
unit
failure when
the
testboard is left unattended.
• A key to enable the
CO
service
alarm
on a
trunk
failure when
the
testboard is
left
unattended.
• Twelve
pickup
keys
that
are
used
in
coordination with the telephone circuits so
that
incoming calls can be identified
by
an
illuminated lamp under
the
key.
• A feature
that
allows conference calls
to
be
set up by bridging telephone lines.
ISS
2,
SECTION
666-600..1
01
1.08 A KTU shelf assembly is associated
with
the
950B
testboard. The KTU shelf assembly
provides a maximum of
12
telephone lines. A
second KTU shelf
may
be used to provide
an
additional
12 lines.
If
a CALL DIRECTOR®
telephone, private
branch
exchange (PBX), etc, is
to be connected to
the
lines between
the
testboard
and
the
KTU shelf, a KS-19252 bridging
adapter
must
be used.
1.09 The
transmitter
and
receiver DTSs
are
mounted in
the
control panel
and
writing
shelf assembly of
the
testboard. The
transmitter
DTS is used to generate
test
signals
and
control
codes for loopback
and
straightaway
testing. The
receiver DTS is used to monitor signals
and
detect
and
display errors.
1.
10 The MSU is used to gain access
to
any
multipoint junction
unit
(MJU) -port, located
downstream from
the
MSU, for
testing
purposes.
After
the
MSU
has
gained access to a desired MJU
port,
the
transmitter
and/or
receiver DTS can
then
be used to
test
the local customer channel by
performing
loopback
tests
as
in
point-to-point
operation.
1.11 The control code
generator
can
generate
11
control codes: 9
are
presently generated
plus
the
ALL 1's code which
are
available on a
switch-selectable basis
at
four outputs simultaneously.
The
test
code is available continuously
at
each of
the
four
test
outputs simultaneously
with
the
DSTU
and
six
test
outputs
without
the
DSTU. The control
and
test
code generators
are
used in place of
the
transmitter
DTS when repeated control codes
are
requiredduringprolonged
testing
from
the
testboard.
1.12 Jack circuits in
the
testboard
provide access
to individual lines (customer channels)
and
interoffice
trunk
circuits
brought
into
the
testboard.
·
In
an
MJU network,
the
jack
circuits provide access
to each
port
of every MJU in
the
hub
office.
Supplemental jack bays
are
also available for use
with
the
testboard when
the
number of customer
channels exceed the
number
of
jack
circuits in
the
testboard
and
another fully equipped
testboard
is
not
needed
just
to provide
the
extra
jack
circuits.
1.13 The TFD provides a centralized display
of
alarm
conditions
for
up to
64
trunk
circuits.
Supplemental units
are
also available to expand
the
capacity of the TFD.
Page 3

SECTION
666-600-101
1.14 All
test
equipment
in
the
testboard
is
synchronized by the timing supply (TS).
The testboard is provided with two clock lines from
the
TS, designated "A"
and
"B"
and
either
one
of
the
lines can be selected
and
connected to
the
clock circuit. The clock circuit derives
an
8-kHz
and
a 64-kHz clock signal from
the
composite TS
signal
and
uses
them
to synchronize
the
SDDS
test
equipment. The clock circuit distributes
the
clock
signal to
the
test
equipment
and
provides necessary
alarms
for absence of clock.
1.
1
5 Cord reels
are
used to provide access from
the MSU
or
the
transmitter
and receiver,
DSTU and outputs from
the
control
and
test
code
generator to
the
jacks in
the
jack
panels.
1.
16 The
950B
testboard can be used to
test
a
data
service
unit
(DSU), channel service
unit
(CSU), office channel
unit
(OCU), service
channels between
the
STC and
the
units,
an
MJU,
subrate
data
multiplexer links
at
the
DS-0 (64-kb/s)
level,
and
through
the
758C
switch.
For
information
concerning
the
units
and
channels tested by
the
950B
testboard,
refer
to
the
following Bell System
Practices:
SECTION
314-901-500
314-910-500
314-911-501
314-911-502
314-917-500
595-100-500
Page
4
TITLE
Digital
Data
System-Serving
Test
Center-Private
Line
Circuit-
Test Procedures
DigitalDataSystem
-Office
Channel
Unit
(OCU)
Assembly-Test
Procedures
Digital
Data
System-Subrate
Data
Multiplexer-Initial
Tests
Digital
Data
System-Subrate
DataMultiplexer-Trouble Location
and
Correction Tests
Digital
Data
System-Multipoint
Junction
Units
and
Auxiliary
Circuits-
Test Procedures
Digital
Data
System-550A-Type
Channel
Service
Unit-Test
Procedures
SECTION
595-300-500
TITLE
Switched Digital
Data
System-
SOlA-Type Switched
Data
Service
Unit-
Test Procedures
1.17
The
950B
testboard can be used in performing
the
following tests:
(a)
Straightaway
tests
from STC to customer
location
or
vice
versa
to
verify
proper
operation of installations
and
to isolate trouble.
The
tests
require a telco employee
at
the
customer
location with
test
equipment (912A, 914-type,
or
921A
DTS).
(b) Remote loopback
tests
from
the
test
board
to
the
interface side of
the
DSU, channel
side
of
the
CSU,
or
channel side
of
the
OCU.
(c) STC to
another
STC
dynamic
test
to
verify
proper facility operation.
(d) Signal tracing
tests
can be performed by
transmitting
the
test
code (00011100)
through
the
system.
(e) Remote loopback
tests
of
trunks-near-end
or
far-end loopback
test
by means
of
test
line in
the
758C
switch.
2.
PHYSICAL
DESCRIPTION
2.01
This
part
contains a description
of
the
physical
features
of
the
950B
testboard
and
the
components in
the
testboard, as shown in Fig.
1.
2.02
The J70176C
testboard
is
11
feet 6 inches
in
height
and
is
23
inches wide. The
testboard
is of
the
cable duct-type
arranged
for
2-
by 23-inch mounting plates. The
alarm
indicator
panel is located in
the
upper portion of
the
testboard.
The panel contains
the
following
alarm
indicators:
trunk
failure display fuse
alarm
(TRK
FAIL
DISPL
FA), testboard fuse
alarm
(TST BD FA),
and
power
unit
failure
alarm
(PWR UN
FAIL
ALM).
Keys
and
indicators for
the
trunk
failure
alarm
cutoff (TRK
FAIL
ACO),
and
testboard
fuse/power
unit
failure
alarm
cutoff (TST
BD
F
/PWR
UN
FAIL
ACO)
are
also located on
the
alarm
indicator
panel.
2.03
The TFD (J98722C) located below
the
alarm
indicator panel,
has
64
trunk
status
indicator

(SI) LEDS
or
lamps arranged
in
a
matrix
of
16
columns and 4 rows.
In
addition
to
the Sis, each
unit
contains a row of horizontal indicator lamps
with associated driver (CP1)
and
vertical indicator
lamps with associated driver (CP2). A
status
cutoff
key (SCO)
and
lamp
test
(LT) keys
are
located on
the left side
of
the TFD. When necessary, up to
three
supplementary
trunk
failure display (STFD)
units (J98722D) can be mounted below
the
initial
unit. The
rear
of
the
TFD (Fig. 2) contains
the
following:
Note: The numbers precedingeach description
below correspond
to
the
numbers in Fig.
2.
(1)
Two KS-16672 L-10 connectors (J1
and
J2)
for connection from
the
trunk
circuit
distribution
frame
to a maximum of four
horizontal indicator drivers (CP1).
(2)
One KS-16786, L-2 connector (J3)
for
connection
to
a STFD.
(3) One
285A
terminal
strip
for connection to
the
fuse block located
at
the
rear
of
the
alarm
indicator panel.
(4) Five
927B
printed circuit board connectors
for up to four CP1s
and
one CP2.·
2.04
Beneath
the
TFD assembly, space is provided
for up to
ten
jack panels (KS-21042-L3)
according to
the
number of STFDs required. Each
2
A
I
0
t\
t
0\
\
J0
(..
le}
0
J2
J3
""0
0
0
ISS
2,
SECTION
666-600-101
jackpanel consists of
30
six-jackmodules (KS-21156-Ll
through
L30); therefore,
the
testboard
can contain
up to
300
modules. The jacks in
the
modules
are
miniature-type telephone jacks. A colored pin is
located
in
the
middle
of
the
top four
jacks
in each
module to indicate
the
data
rate
of
that
particular
channel (Fig. 3). Dummy plugs can be inserted
into
the
jacks for opening channel lines
at
the
testboard. Designation signal plugs
are
also available
for
priority
circuits to
prevent
channel service from
being inadvertently
interrupted
at
the
testboard.
Designation labels above each
jack
module can be
marked so
that
data
channels can be identified.
2.05
Supplemental
jack
bays (ED-73449-30), used
to provide additional
jack
appearances,
may
be located adjacent
to
the
testboards
and
are
available in 7-foot
or
11-foot 6-inch heights. The
jack
bays
are
available
in
two configurations: one
configuration is a
jack
bay with a
writing
shelf
assembly
and
space for up
to
15
jack
panels (450
six-jack modules)
and
the
other
configuration is a
bay with space for up to
26
jack
panels (780 six-jack
modules).
2.06
Immediately below
the
jack
panel is space
for
up
to six cord reel units. Each cord
reel
unit
(ED-73469-30) contains two plugs
and
four
KS-21001-L1 jacks. Connection
to
the
cord reel is
at
the
KS-19088-L7 connector on
the
rear
of
each
cord reel unit. On
the
right
side of
the
cord reel
units
are
four DRSIU access jacks, which
are
3
I
J
a-----a
a-----a
~
[!
a-----a
a-----a
A
0
0
0
0
4
I
4
a-••
--
•a-•
CP1
--··-----·---·
3
====-=-=-::=:
CP1
2
====-=-=-::=:
CP1
:=:=-=-=-==-=
CP2
0
0
0
'---
0
-'---v-~-s
-~-~-~-o-~_o_~_o_~_go_~_o_~-~-~-~-
5
-~-~-~-~-
1
-~-~......L....L-:----1
~-----=-:_8k_l~
_1
_
__,;:;_
Fig.
2-Rear
View
of Trunk Failure Display
Page 5

SECTION
666-600-101
FROM
FAR
TO
NEAR
MON
FAR
~1
~
\
*DATA
SPEED
COLOR
CODE
TO
FAR
FROM
NEAR
MON
NEAR
*
THE
DATA SPEED
COLOR
CODES
ARE
AS
FOLLOWS:
PIN COLOR DATA SPEED
( kb/s l
ORANGE
2.4
YELLOW
4.8
GREEN
9.6
8WE
!56
Fig.
3-Jack
Module
connected via DRSIU
test
lines to the DRSIU
at
the
758C
switch.
2.07 The DSTU is located
just
below
the
cord
reel units. The DSTU is held in place by
screws
in
each
of
two mounting brackets, which
are
on
the
sides of
the
DSTU. A clock cord
and
a power cord with connectors
at
one end
are
furnished with
the
testboard. A signal cord is
supplied with
the
DSTU. The cords have 5-pin,
3-pin,
and
15-pin connectors, respectively. The
signal cord plugs into
the
cord reel unit;
the
clock
cord
and
power cord plug into
the
DSTU. Functions
of
the
controls
and
indicators on the DSTU
are
covered in Section 107-602-100.
2.08 The
transmitter
and
receiver DTSs
are
located in
the
control panel
and
writing shelf
assembly (J70176AA) (hereafter referred to as
the
"control panel") below
the
DSTU. The
test
sets
are
held in place by a sliding bracket located on
the sloping shelf so
that
they can be removed for
portable use.
Page
6
2.09
The receiver
and
transmitter
DTS signal
cords plug into
the
RCV
(KS-21001-Ll)
and
TRMT (KS-21001-L1) jacks, respectively, in
the
rear
of
the
control panel. The
RCV
and
TRMT
jacks
are
then
connected through a cable
to
the
rear
of
the
MSU when
the
MSU is provided;
otherwise,
the
RCV
and
TRMT jacks
are
connected
to
the
connector on
the
rear
of a cord reel unit.
The
dock
cords from
the
test
sets
are
inserted
into a 5-pin male connector located
at
the
top
rear
of
the
equipment shelf. The power cords plug
into a duplex receptacle on
the
rear
of
the
control
panel.
2.10 The
front
panel ofboth DTSs containswitches
to
condition
the
test
set
for transmission
or
reception
of
data
and
indicators
[lamps
and
light-emittingdiodes (LEDs)] to indicate
the
position
and
status
of
the
switches. The controls
and
indicators on
the
receiver
are
described in Section
107-601-100. The controls
and
indicators on
the
transmitter
are
described in Section 107-600-100.
2.11 The push-to-talk telephone
handset
located
on ·the control panel is a G5G
R-61
handset
and
is connected to
the
telephone circuitry in
the
950B
testboard
via a
latching
cord reel unit.
Located below
the
handset
is a
pair
of
223A
jacks
to be used for connection of a headset. An 8J
rotary
dial
or
a 35Y3A TOUCH-TONE dial is used
in conjunction with
the
handset.
2.12 The
CONT
CODE switch, located on
the
control panel below
the
receiver DTS
and
to
the
right
of
the
handset, is a 12-position
rotary
switch. The codes
are
printed above
the
switch
and
the
numbers adjacent to
the
codes correspond
to
the
switch positions.
2.13 The MSU control panel, located below the
receiver DTS
and
to
the
right
of
the
CONT
CODE switch, contains
the
following:
• A momentary contact pushbutton switch
(DISPLAY TEST) associated
with
the
display
readouts.
•
Eight
pushbutton
keys (TST, SIG, CLR,
BLK,
and
four
BRANCH keys)
with
a
328-type lamp located under
the
TST, SIG,
and
CLR
keytops.
• A display which is divided into two sections
(OLD
and
NEW) with each section containing

two LED readouts for
the
hub identification
(HUB ID) code
and
one LED readout for
the branch (BR) number. Each LED readout
contains seven segments.
• The BLK (block) key is reserved for
future
applications.
2.14
The telephone key assembly, located below
the
transmitter
DTS
and
to
the
left
of
the
dial, may contain
12
pickup keys, a HOLD key, a
TEL
ALM
key (optional), and
an
AUD OFF key.
Each of the keys is push-to-operate and push-to-release
type equipped with a 51A lamp. The pickup keys
and
the
TEL
ALM
key contain clear plastic keytops.
The HOLD
and
AUD OFF keys contain a red
and
an amber plastic keytop, respectively. Designation
tabs
appear under
the
plastic keytops so
that
the
keys can be identified.
2.15
When more
than
one 950-type
testboard
is
installed in a hub office, A25D connector
cables may be used to connect
the
telephone circuits
between testboards
are
shown in Fig.
4.
The
cables
are
connected to 66E3 connector blocks on
the
rear
of
the
control panel.
2.16
The
CLOCK
switch, located to
the
right
of
the
dial, is a 3-position
rotary
switch. A
clock failure lamp is associated with
the
CLOCK
switch and is located directly above it.
2.17
The
rear
of
the
control panel contains
the
following:
Note:
The numbers preceding each description
below correspond to
the
numbers
in
Fig.
5.
(1) Two KS-21001-L1 signal jacks,
J9
and
J10
(labeled
RCV
and
TRMT, respectively).
(2) Three KS-19088-L7 connectors:
•
P8-Connects
to
the
two signal
jacks
J9
and J10.
•
P12-Connects
to the CONT CODE switch.
•
P14-Connects
to
the
CLOCK switch, clock
alarm
circuitry
and
lamp,
and
to
the
two
clock connectors on
the
rear
of
the
equipment
shelf.
ISS
2,
SECTION
666-600-101
(3) One 8-contact
terminal
strip
(TSA) labeled
CLK-Connects
to
the
CLOCK switch
and
terminates
the
lines from
the
TS.
(
4)
One 3-contact
terminal
strip
(TSB)-Connects
to
the
PWR
SUP
and
DIAL fuses
and
terminates
the
CO
battery
lines.
(5) Two 70D-type fuses
rated
at
5A
and
labeled
PWR SUP
are
the
following:
•
F2-Handles
power to
the
74A
or
78A
power units
•
F3-Handles
power to
the
71D
or
76D
power units.
(6) One 70A-type fuse (F1)
rated
at
1-1/3A
and
labeled
DIAL-Handles
power to the telephone
circuitry.
(7) One duplex 117-volt ac
receptacle-Supplies
power to
the
transmitter
and
receiver DTSs.
(8) Two 66E3 connecting blocks:
• TSF
-Connects
the
KTU shelf assembly
or
connecting block
TSH
of
the
preceding
testboard to connecting block TSG
•
TSH-Connects
the
succeeding
testboard
to
the
KTU shelf assembly.
(9) One 66E7 connecting block
(TSG)-Connects
to connecting blocks TSF, TSH,
and
the
pickup key assembly.
2.18
An equipment shelf (J70176AB) is located in
the
lower section of
the
testboard
and, when
fully equipped, contains one 74A
or
78A power
unit, one
71D
or
76D
power unit,
and
six circuit
packs (CPs)
as
follows:
• HL49B line
terminator
• HL52 clock line driver
• HL66 control
and
test
code
generator
• HL67 line drivers
• HL81 MSU mode control
and
timing
• HL82 MSU
input/output
and memory.
Page
7

SECTION
666-600-101
950-TYPE
TESTBOARD
I
KTU
SHELF
(J70176ACl
NOTE:
950-TYPE
TESTBOARD
2 -
_.....;..
______
_
950-TYPE
TESTBOARD
6
ALL
CONNECTIONS
ARE
MADE
WITH
A250
CABLES
OR
EQUIVALENT
Fig.
4-lnterconnection
of
Telephone
Circuits
Between
950-Type Testboards in a Multi-Testboard Installation
~
,
..
~
)a 0
0
00
lr.
~ ~
T
: I
~
ij
I
•
v
T
<D <D
.._
~
~
h
m~m~~
~
PI~
~
0
~
Ia
~
\ /
SA
H/H
\.
Fl
fl
"
\_
_/
~
\_
'
8 9 8 7
Fig.
5-Rear
View
of
Control
Panel
The
74A
and
78A
power units
are
de-to-de converters
which require -48
and
-24 volts, respectively, from
the
CO
and
have
an
output of +5 volts
and
-12
volts de. This power
unit
provides +5 volts to
all
the
above CPs plus
the
controls and displays
of
the MSU
and
the
clock
alarm
circuitry
and
lamp.
It
also provides -12 volts to the DTSU.
The second power
unit
is also a de-to-de converter
and
may
be
a
71D
or
76D
that
requires -48
or
-24
volts, respectively from
the
CO.
It
provides +5
volts to
the
DTSU.
2.19
The
rear
of the equipment shelf contains
the following:
Note: The numbers precedingeach description
below correspond to
the
numbers in Fig.
6.
(1) One KS-19088-L16 male connector (P1) which
is wired to HL67 CP supplies
the
control
and
test
codes, via a cord, to
the
cord reel units.
Page
8
(2) Two KS-19088-L7 male connectors: One
connector
(Pll)
is wired to HL66 CP
and
connects
the
CONT CODE switch via a cord to
HL66 CP. The
other
connector (P13) is wired
to HL49B
and
HL52 CPs
and
one
74A
or
78A
power unit. This connector, via a cord, supplies
clock signals to two auxiliary clock plugs (P19
and
P20), supplies power to
the
clock
alarm
circuitry, connects
the
line
terminator
(HL49B
CP) to
the
clock
alarm
circuitry,
and
connects
the
CLOCK
switch to
the
line
terminator
CP.
(3)
Two 5-pin male clock connectors (P17
and
P18) which
are
wired
to
HL52 CP
and
supply
clock signals to
the
transmitter
and
receiver
DTSs.
(4)
One KS-16672-L12 female connector (J28)
which is wired to HL81 and HL82 CPs
and
connects to
the
MSU control panel via a cord.

ISS
2,
SECTION
666-600-1
01
/I
2\
3\
t
3\
2\
I
.---
I " \
I
\
\
I
f--
0 I
\1
~
n/
1-~
1 0
u u
----
0
0
......._
f-.-
.
~""";'""
r-;-
r-:-
r-;-
.
•
r-:-
. .
.--
....--
1--
0 0
f--
~
~
-7
~
~
1--
.....:...
.
.......:....
. .
L-
L----
.__
L--
\
0 \
49
34
31
27
24
21
19
17
0
\,
\
6
7
Fig.
6-Rear
View
of Equipment Shelf
in
a
9508
Testboard
(5) One 2-contact
terminal
strip
(TSC)
that
connects
the
74A
or
78A,
and
71D
or
76D
power units to
CO
battery
lines via TSB
and
fuses F2
and
F3.
(6)
Eight
940A
printed circuit board connectors.
(7) One 15-pin
terminal
strip, TSF, used for
ground connections.
2.20
Two auxiliary clock plugs (P19
and
P20)
are
also located under the writing shelf
and
are
wired to HL52 CP.
2.21
The KTU shelf assembly (J70176AC) (Fig.
7) is equipped with a KS-19175-11 interrupter,
a relay, a 19C2 power unit,
and
400D
and
416A
KTUs
as
required. The
19C2
power
unit
supplies
power to
the
interrupter, relay, KTUs, buzzer,
and
testboard key assembly lamps. The power
cord for
the
19C2
power unit is available in 1-1/2,
2-, 4-, 6-,
and
12-foot lengths.
A25D
cables (or
equivalent) connect
the
KTU shelf (or shelves) to
the
testboards. The cables plug into 66E3 connecting
blocks on
the
rear
of
the
control panel. One KTU
shelf can hold a maximum of
12
KTUs. The KTU
shelf can be equipped with 400D
and
416A KTUs
according to
job
requirements. Positions 1
through
4 in
the
shelf
are
for
416A
KTUs only, while
positions 5 through
12
are
for 416A
or
400D KTUs.
The HOLD key in
the
testboard
key assembly
functions only with
400D
KTUs. The KTU shelf
assembly can be located above
the
jack
panels
or
in a remote bay.
3. FUNCTIONAL
DESCRIPTION
3.01
This
part
contains
the
basic
functional
operation of the test equipment and components
in
the
950B
testboard.
3.02
The
alarm
indicators display failures of
the
power units,
testboard
fuses,
and
trunks.
When
the
testboard is
left
unattended,
the
alarms
.
can be connected to
the
CO
service
alarm
via
the
TRK FAIL
ACO
and TST
BD
F
/PWR
UN
FAIL
ACO
keys.
3.03
The TFD below
the
alarm
indicator panel
provides a centralized display of
trunk
alarm
conditions. When a
trunk
failure occurs, a
status
indicator (SI) assigned
to
that
trunk
will light. A
corresponding horizontal (HI)
and
vertical (VI)
indicators will light to indicate
the
grid
location of
the
lighted SI. The SI will remain lighted only
when
the
alarm
condition
is
present. The
HI
and
VI
lamps
are
locked in
and
will
remain
lighted
until
they
are
manually cleared by operation
of
the
SCO
switch. Additional failures can be displayed
without disturbing
the
initial
failure indication.
Page 9

SECTION
666-600-101
RELAY
w
...
t.rlt
£1•drl~
POWER
UNIT
0
KS-19175-LI
INTERRUPTER
Fig.
7-Key
Telephone Unit Shelf Assembly
Lamp
test
keys
are
provided to
test
the
SI, VI,
and
HI
lamps.
For
a detailed description of
the
circuitry, controls
and
indicators on
the
TFD,
refer
to
Section 365-330-110.
3.04
All line
and
trunk
circuits in
the
SDDS pass
through
the
950B
testboard
at
the
switch
hub office,
and
may be monitored (bridged)
or
opened by line jacks
or
trunk
jacks on the
testboard
(Fig. 8). The jacks in
the
jack panels
are
used to
monitorcustomer
data
or
test
signals and to
transmit
and
receive
test
signals
at
the
testboard. The
stations associated with a customer channel
and
brought into a
jack
module
must
be identified
as
either
far
end
or
near
end to correspond to
the
designations on the jack modules (Fig. 3). Line
jacks with the FAR designation
are
connected to
line circuits toward
the
758C
switch (Fig. 9). Line
jacks with
the
NEAR designation
are
connected to
lines toward the local channel.
Trunk
jacks
are
located on
the
opposite side of
the
switch from
the
line jacks (Fig. 8
and
10). Their function is
similar to
that
of
the
line jacks. When
the
RCV
cord reel plug is inserted into
either
one of
the
two monitor jacks,
the
channel is not
interrupted
and
data
can be monitored without disrupting
the
circuit. The
MON
NEAR
jack
permits monitoring
of
signals from
the
near end. The
MON
FAR
jack
permits monitoring of signals from the
far
end.
When
the
RCV
cord reel plug is inserted into
either
the FROM NEAR
or
FROM FAR jack,
the
channel
pair
is opened
at
this
point
and
data
or
test
signals
from
either
the
near
or
far
end can be checked
Page
10
at
the testboard. When
the
TRMT, CONT CODE,
or
TEST CODE plug is inserted into
either
the
TO
NEAR
or
TO
FAR jack,
the
channel
pair
is
opened
and
test
signals can be
sent
to
either
the
near
or
far
end from
the
testboard.
3.05
The cord reel plugs
are
used to connect
the
transmitter,
receiver, MSU, DSTU,
and
control
and
test
code generator to
the
jacks
in
the
jack
panels. The cord reel plugs
are
inserted
into
the
jacks in order to connect
the
transmitter,
receiver, MSU, control
and
test
code generator,
or
DSTU to the desired channel. Refer to Fig.
11
for cord reel designations. Connection
to
the
transmitter
is available
through
one cord reel plug.
Connection to
the
receiver
is
also available
through
only one cord reel plug. Connection to
the
control
code generator is available through four cord reel
plugs. Connection to
the
test
code
generator
is
available through four cord reel plugs
with
the
DSTU provided
and
six cord reel plugs
without
the DSTU. The
test
code is simultaneously available
on
the
test
code jacks, regardless
of
the
CONT
CODE switch setting. Connection to
the
DSTU is
available through two cord reel plugs; one for
receive
and
one for
transmit.
Two additional logic
level jacks (labeled
LLO
and
LLI)
are
provided to
allow far-end loopback
and
error
runs
over a
completed call circuit using
the
transmitter
and
receiver DTSs. Connection to
the
MSU is available
through
the
transmitter
and
receiver cord reel
plugs when
the
MSU SIG key is depressed. Access
to
the
transmitter,
receiver, MSU, control
and
test

code generator
and
DSTU can also be made by
meansof patch cordsfrom thejacks in
the
associated
cord reel units. The cords in
the
cord reel units
are
long enough to
permit
the
cord reel plugs
to
be
inserted into jacks in adjacent bays. The two
inner jacks located between
the
output
plugs on
the
front
of each cord reel
unit
(and
MON
jacks
on
the
DSTU cord reel unit) can also be used to
monitor
the
signals on the cord reel units. The
jack on
the
left side of
the
cord reel
unit
is
associated with
the
plug on
the
left
side
of
the
same cord reel
unit
and
the
jack
on
the
right
side
is associated with
the
plug on
the
right
side of
the cord reel unit.
3.06
The DRSIU jacks
at
the
right
of
the
cord
reel units provide access from
the
DSTU
at
the
758C
switch to
the
950B
testboard,
and
through
the testboard line
and
trunk
jacks to
any
point in
the
system.
3.07
For
a functional description of
the
circuitry,
controls, and indicators on
the
DSTU,
refer
to Section 107-602-100.
ISS
2,
SECTION
666-600-101
3.08
For
a functional description
of
the
circuit:cy,
controls, and indicators in
the
receiver
and
the
transmitter
DTSs,
refer
to Sections 107-601-100
and
107-600-100, respectively.
3.09
The MSU controls
and
display (Fig. 12)
function as follows:
• DISPLAY TEST
-Operation
of
this
key
causes all seven segments of each LED
readout in
the
display to light. Numbers
appearing in
the
display
at
the
time
the
key
is depressed will
not
be erased,
but
will
reappear when
the
key is released.
• TST
key-Operation
of
this
key connects
the
transmitter
and
receiver signal cords to
the
TRMT/RCV cord reel
unit
through
relay
contacts
in
the
MSU. A
lamp
under
the
keytop lights when
the
key is depressed
if
the
SIG key
has
been depressed
and
an
MJU
branch
has
been selected. The
lamp
is
not
lighted when
the
transmitter
and
receiver
are
being used for private line point-to-point
testing.
SODS
HUB
OFFICE
SWITCHING
SYSTEM
758C
SWITCH
--------
/
'\
I
,,-
....
,
\
I I
I
DLC
I I
DTC
I
LINE
JACKS
TRUNK
JACKS
"
,
TO
fROM
TO
fROM
LINE
NEAR
fAR
NEAR
fAR
./
-
SDOS
CUSTOMER
MON MON MON
NEAR
fAR
NEAR
'"
fROM
TO
fROM
TO
NEAR
fAR
NEAR
fAR
-
d
"'
"'
""
,..,
950B
TESTBOARD
JACKS
Fig.
8-Location
of
9508
Testboard Jacks
in
SDDS
TRUNK
-
MON
fAR
-
TOWARD
DISTANT
CUSTOMER
Page
11

SECTION
666-600-101
Page 12
"X
TO
CUSTOMER
LINE
TO
'
758C
SWITCH
(VIA
TRUNK CKT)
-
w
z
--
y
X
~l
n.
~"''"
'"~rL_
FAR
A~
MON
~
v
FAR
A
~l~·
~A
NEAR
rc
~~.1
V~MON
NEAR
Fig.
9-Line
Jacks
nMON
U
NEAR
MON
n
FAR
U
Fig.
10-
Trunk
Jacks
"'
TO
758C
SWITCH
(VIA
LINE
CKT)
TOWARD
FAR
SWITCH

®I
~~~~
I
oooo
I
~~~:
I®
®I~~~~
I
oooo
I~~~~
I®
RCV
JACK
LOGIC LEVEL
OUT
JACK
TRMT JACK
LOGIC LEVEL
IN
JACK
ISS
2, SECTION
666-600-1
01
®I~~~~
1
oooo
1
~~~~I®
®I~~~~
I
oooo
I~~~;
I®
Fig.
11-Cord
Reel Designations
MSU
DISPLAY
•
TEST
HUBIO
BR
Fig.
12-Front
View
of MSU
• SIG
key-Operation
of
this
key connects
the MSU
transmitter
and receiver to
the
TRMT/
RCV
cord reel unit. A lamp
under
the keytop lights when
the
key is depressed.
• BLK
key-Reserved
for
future
applications.
• CLR
key-Operation
of
this
ke
y causes
the
MSU
to
send
idle
code
to
the
MJU
s
downstream
and
remove
them
from
the
test
mode. A lamp
under
the
keytop will
light
for approximately one-half second when
the
key is depressed. The
lamp
will also flash
if
the
CLR key is
not
depressed
before
the
TRMT cord reel plug is removed from
the
testboard
jack
after
an
MJU
has
been
signaled.
• BRANCH keys
(1
through
4)- These keys
are
used to select
the
proper
MJU
port
s
required to gain access to a desired s
tation
downstream in
private
line service.
Ea
ch
operation of a BRANCH key selects one
port
out
of each MJU located between the
MSU
and
the
station
to be checked
until
a
path
between
the
two is complete.
In
each
case
the
port
selected corresponds to
the
number on
the
BRANCH key. A
path
between
an
MSU
and
a
station
when
the
appropriate
BRANCH keys
are
depressed is
shown in Fig.
13.
When a BRANCH key
is depressed,
the
MSU sends
80
consecutive
bytes to an MJU downstream. The
80
bytes
are:
20
bytes of
test
alert
(TA)
20
bytes of MJU
alert
(MA)
20
bytes of
branch
code (BR1-4)
20
bytes of unassigned mux c
han
(
UM
C).
Page 13

SECTION
666-600-101
•
Display-
The MSU display will show
branch
(BR) numbers
and
hub identification (HUB
ID) codes received from MJUs selected by
the
BRANCH keys. The display will show
BR numbers
and
HUB ID codes as follows:
(a) When only one BR number
and
HUB ID
code is received,
they
will appear
in
the
NEW section of
the
display.
(b) When two BR numbers
and
HUB ID codes
are
received,
the
last
one received will
appear in
the
NEW section
and
the
remaining
one will appear in
the
OLD
section of
the
display.
(c) When more
than
two
BR
numbers
and
HUB
ID codes
are
received,
the
display will show
the
last
two received.
After
all BRANCH keys
are
depressed,
the
display will only show
the
last
two BR numbers
and
HUB ID codes received.
The
last
BR
number
and
HUB ID code received
will appear in
the
NEW section
and
the
next
to
last
BR
number
and
HUB ID code will
appear
in
the
OLD
section of
the
display. Figure
14
lsso-~P;-1
I
TESTBOARO
I
I
MSU
I
I I
I
,...,_--+
I I
MJU
(I~
-+-2----1...
3
4
MJU
(21)
MJU
(22)
.......
'
.......
, 2
shows
the
sequence
of
BR numbers
and
HUB
ID codes displayed when MSU BRANCH keys
are
depressed in order to access
the
station
specified in Fig. 13. Figure 14,
parts
A,
B,
and
C show
the
BR numbers
and
HUB ID codes
displayed
after
BRANCH keys
2,
2,
and
3
are
depressed, respectively. Figure 15 shows
the
sequence of operation followed when
an
MSU is
used to gain access
to
a desired station.
3.1 0
The telephone
handset
and
dial
are
used
with two types of line circuits: a
station
line circuit (416A KTU)
and
a
CO
line circuit (400D
KTU). The
station
line circuit is 2-wire
and
provides local voice communication via
an
interbay
talk
trunk
with SDDS equipment bays. One-way
signaling to
the
testboard
is provided when a telco
employee inserts his headset pluginto
the
appropriate
jacks
at
the
bay clock, power,
and
alarms
shelf.
The
CO
line circuit provides 2-way
automatic
signaling so
that
communication between
an
STC
and
another
STC
or
other
local
or
remote
testboards
is possible. The
CO
line circuit also provides access
to
the
direct distance dialing (DDD) network. The
*
THIS
STATION
IS
CONNECTED
TO
THE
MSU
WHEN
BRANCH
KEYS
2,
2,
AND
3
ARE
DEPRESSED
IN
THAT
ORDER.
L
___
:J
~--------------~
Page
14
MJU
(23)
2
MJU
(47)
Fig.
13-Connection
of
MSU
to a Desired Station
by
Selection
of
Proper
MJU
Branches

OLD
HUB
lD
1
I
OLD
HUB
ID
OLD
-,
I
-
HUB
ID
BR
BR
-
I I
.I=-
BR
NEW
I I
-,
I
1.1=
A
HUB
ID
BR
NEW
-,
I
-,
c~
~=
.1=
8
HUB
ID
BR
NEW
I I
-,
=I
=1.=
I
c
HUB 10
BR
Fig.
14-MSU
Display After Depression
of
Branch
Keys
telephone circuits also make
it
possible to have
conference calls with several persons; however, a
reduction in level occurs
as
each additional telephone
line is bridged for a conference call.
3.11 The pickup keys on
the
control panel
are
provided
so
that
calls can be placed from
and received
at
the
testboard. The
lamp
under
the
keytop lights when
the
key is depressed,
and
flashes when a call is being made to
the
testboard.
The flashing key
must
be depressed to establish
connection to
the
line over which
the
incoming call
is being made. Outgoing calls can be made on
CO
lines only.
3.12
The TEL
ALM
key permits activation of
the
central office service
alarm
when
an
incoming call is being received
at
the
testboard.
When
the
testboard is left unattended,
the
CO
service
alarm
will
alert
CO
personnel
of
an
incoming
call. Where multiple testboard installations occur,
the
TEL
ALM
key is located only in
the
testboard
that
connects directly to
the
KTU shelf. When
more
than
one KTU shelf is associated
with
a
group of testboards,
the
TEL
ALM
key can be
ISS
2, SECTION
666-600-1
01
multipled to
the
testboards associated
with
the
particular
KTU shelves.
3.13
The HOLD key permits
the
testboard
operator
to hold a
CO
line. When a line is placed
on hold, the pickup key
lamp
associated
with
that
line will wink.
3.14
The AUD OFF key is used to disable
the
buzzer. When
an
incoming call is being
received,
the
AUD OFF
lamp
will flash
at
the
same
rate
as
the
buzzer would normally buzz.
3.15
The
400D
KTUs in
the
KTU shelf provide
pickup
or
hold of a
CO
line when a call is
placed to or received from
another
STC
or
other
location. The 400D KTUs also cause
the
buzzer
to sound
and
the lamp under
the
keys to
light
on
an incoming call;
the
KTUs cause
the
HOLD key
lamp to light when
the
key is in
the
hold condition.
The 416A KTUs provide a
station
line circuit so
that
one-way signaling
from
SDDS
equipment
locations in a hub office to
the
testboard
can be
accomplished via an
interbay
talk
trunk.
The 19C2
power
unit
on
the
equipment
shelf
requires 117
volts ac
at
60
Hz. The power
unit
provides
10
volts ac
and
-24 volts de
and
delivers
it
to
the
KTUs,
the
buzzer,
the
interrupter,
the
relay
and
lamps in the testboardkey assembly. The
interrupter
is driven by an ac motor
and
it
gives
the
telephone
buzzer
an
alternating
on
and
off sequence. The
relay
operates on incoming calls
and
provides
power to
the
interrupter
through
a
set
of contacts.
Two
other
sets of relay contacts, in conjunction
with
the
operated TEL ALM key, activates
the
CO
service
alarm
when
an
incoming call is being
received.
3.16
The
CLOCK
switch selects
either
one
of
two bipolar clock lines (A
or
B)
brought
into
the
testboard
and
connects
the
line to
the
clock
line
terminator
(HL49B CP). The switch also
checks
the
clock failure
lamp
for proper operation.
WhEm
the
switch is operated to
the
middle position,
the
clock failure lamp, located above
the
switch,
should light.
If
the
lamp
lights when
the
CLOCK
switch is in position A
or
B,
this
indicates a loss
of clock
or
faulty clock on line A
or
B,
respectively.
3.17
The clock line
terminating
circuit (HL49B
CP) and
the
8-
and
64-kHz clock driver board
(HL52 CP)
are
located in
the
equipment shelf
and
are
associated with the clock
timing
signals. HL49B
CP provides
the
proper terminationfor
the
composite
Page
15

SECTION
666-600-101
MSU
SIG Key Depressed
(Connects
the
MSU
Transmitter and Receiver
to
the
TRMT/RCV Cord Reels)
BRANCH Key Depressed
(MSU
Sends a Continuous 80-Byte Command
to
the
MJU)
MJU
20
Bytes
of
TA
------------------------1~
Blocks All Branches
and
Sends
All
Zero Bytes Downstream
Enable
Display+-----------------------
20
Bytes
of
TA
20
Bytes
of
MA-----------------------+
20
Bytes
of
Hub
10
Code
HUB
ID
Code
Displayed4------------------------..J
20 Bytes
of
BR
-----------------------.
Prepares
to
Unblock Selected Branch
Displays Branch Selected
•-------------------
20
Bytes
of
BR
20
Bytes
of
UMC
BRANCH Keys are Depressed Until All
MJUs Have Been Signaled
to
Reach
the
Desired Station
TST Key Depressed
(Connects
the
Transmitter
and
Receiver
Test Sets
to
the
TRMT/RCV Cord Reels)
Test Customer Station
CLR Key Depressed
(Sends
1/2
Second
of
Idle Code)
Unblocks Selected Branch
Normal Operation
Fig.
15-0perational
Sequence
of a Multipoint
Signaling
Unit
clock signal selected by
the
clock switch. The
bipolar clock signal is a composite signal which
contains both the 8-kHz
and
64-kHz timing signals.
HL49B CP separates the
8-
and
64-kHz signals from
the
incoming clock signal
and
checks to see
if
they
are
present
and
in proper alignment.
If
the
incoming
clock signal is
out
of
alignment
or
is not present,
the
lamp located above
the
clock line switch lights.
The logic
output
from HL49B CP is
sent
to
the
driver board HL52 CP which distributes
the
timing
signals to
the
test
equipment.
Page
16
3.18
The CONT CODE switch can be used to
select each
of
nine control codes
or
an
ALL
l's
code
as
shown in Table
A.
Each
code is a
byte which consists
of
eight bits
and
is produced
by
the
control code
generator
(P
/0
HL66 CP)
located in
the
equipment shelf. HL66 CP also
produces a
test
code which is available
at
the
cord
reel outputs as described previously.
').'he
line
driver circuit pack (HL67 CP) converts
the
unipolar
logic signal of HL66 CP into
the
SDDS balanced
bipolar format
with
+
and
-3
volts amplitude.

TABLE A
CODES SELECTED
BY
CONT CODE
SWITCH
SWITCH
DESIGNATION CODE
POSITION
1 SR IDLE
01111110
2
56
IDLE 11111110
3 DSU LOOP
00101100
4 CHAN LOOP
00101000
5
OCU
LOOP
00101010
6 OUT
SYNC
00011010
7 TEST CODE
00011100
8 UASGN CHAN
00011000
9
NOT
READY
01111010
10,
11
--
ALL
1's
.ALL
l's
11111111
3.19
The CPs associated
with
the
MSU (HL81
and
HL82 CPs)
are
located in
the
equipment
shelf. HL81 CP provides the timing for HL82 CP
and
part
of HL81 CP and, in conjunction with
the
keys on
the
MSU,
it
controls
the
mode of MSU
operation. HL82 CP provides generation
and
recovery
of
certain codes (Table
B)
to
and
from
an MJU.
Screw
switch
Sl
located
on HL81 CP
(Fig.
16)
must
be
in
the
"up"
position
when
the
CO
battery
is
-48
volts
and
must
be
tightened
"down"
when
the
CO
battery
is
-24
volts.
3.20 The power units located in
the
equipment
shelf may be either a
74A
and
a
71D
(-48
volt
CO
battery)
or
a
78A
and a
76D
(-24 volt
CO
battery). The
74A
or
78A
power
unit
provides
+5 volts to
the
CPs
in
the equipment shelf, to
the
clock
alarm
circuit
and
clock
alarm
lamp,
and
to
the
MSU circuitry. A -12 volt
output
supplys
the
DTSU. The
71D
or
76D
power
unit
provides
+5 volts for
the
DSTU.
4.
OPERATION
4.01 This
part
contains operating procedures to
be followed when originating
or
answering
ISS
2,
SECTION
666-600-1
01
TABLE B
CODES GENERATED
BY
THE
MSU
DESIGNATION CODE
TEST ALERT 01101100
MJU ALERT
01110001
BRANCH 1
00101001
BRANCH 2
00101011
BRANCH 3
00101101
BRANCH 4
00101111
UMC
00011000
IDLE
01111110
HUBID
OXXXXXX1
*
* Bit positions 2
through
7 of
the
HUB ID
code can contain a 1
or
a 0 according to
the
office code.
telephone calls, using
the
MSU,
and
sending control
and
test
codes from
the
950B
testboard. Refer to
Sections 107-600-100
and
107-601-100, respectively,
for operating procedures concerning
the
transmitter
and receiver DTSs. Refer to Section 107-602-100
for operating procedures on
the
DSTU
and
Section
365-330-110 for operating procedures for
the
TFD.
Originating a Telephone Call
Note:
Outgoing calls to
other
.STC
testboards,
customers,
and
telco employees in
the
field
can only be placed over
CO
lines. Outgoing
calls
to
local SDDS equipment cannot be placed
over the
station
line circuit.
4.02
To
place a call, depress
the
appropriate
pickup key to make connection to a
CO
line
and
the
lamp under
the
pickup key will light. Dial
the
telephone number of
the
location
to
be called.
Answering
and
Terminating a Telephone Call
4.03 When a call is received
at
a
950B
testboard,
a buzzer
and/or
CO
service alarm,
if
enabled,
will sound
and
the
lamp under
the
associated pickup
key will flash.
To
answer
an
incoming call,
operate
the flashing pickup key. The
lamp
will stop flashing
and remain lighted.
To
disconnect
the
telephone
Page
17

SECTION
666-600-101
· SCREW
~SWITCHSI
Fig.
16-Screw
Switch
S1
on
HL81
CP
line, release
the
same pickup key
and
the
lamp
will extinguish.
Using
the AUD
OFF
Key
4.04
The AUD OFF key is operated
to
disable
the
telephone buzzer when a call is being
received.
Using
the
TEL
ALM
Key
4.05
When
the
TEL
ALM
key is operated,
the
CO
service
alarm
is enabled and
the
lamp
under
the
key lights. When
an
incoming call is
received,
the
service
alarm
will sound
and
the
lamp
under
the
pickup key associated
with
the
call will flash.
Placing
a CO
Line
on
Hold
4.06
To
place a
CO
line on hold:
(1) Originate
or
answer a call.
(2) Operate HOLD key. The HOLD lamp will
light
and
the
pickup
lamp
will wink.
Page 18
(3)
Release pickup key
and
pickup
lamp
will
still wink.
(4)
Release
HOLD
key.
HOLD
lamp
will
extinguish. (Line should now be
on
hold.)
(5)
Originate or answer
another
call.
4.07
To remove a call from hold,
operate
the
pickup key
and
pickup lamp will light.
4.08
To
terminate
a call, release
the
pickup key.
Placing
a Station
Line
on
Hold
4.09
.To place a
station
line on hold:
(1) Answer a call from a DDS equipment location.
(2)
Instruct
the
person
at
the
DDS equipment
location
not
to
remove
the
headset
plug from
the
jacks
in
the
bay clock, power,
and
alarms
(BCPA) unit.
(3) Release
the
pickup key
and
the
lamp
under
the
key should
remain
lighted. (Line should
now be on hold).

(4) Answer
another
call.
4.10
To remove a call from hold, operate
the
pickup key. The lamp under
the
pickup key
will remain lighted
and
voice communication
may
continue.
4.11
To
terminate
a call, request
the
person
at
the
DDS equipment location to remove
the
headset plug from
the
BCPA jacks; then, release
the
pickup key.
Conference Call
4.12
A conference call between several· persons
can be made by performing the following
steps.
Note:
Volume is reduced for each additional
line bridged for conferencing.
(1)
Place a call to
or
answer a call from one
of the stations to be included in the conference.
(2) Place
the
line on hold as described in
4.06
or
4.09.
(3) Place a call to
or
answer a call from
the
other
stationsto be included in
the
conference.
Place these lines on hold.
(4)
After all calls have been made, operate
the
pickup keys associated
with
the
conference
participants.
(5)
The calls can be disconnected by releasing
the
pickup keys.
Multipoint Signaling Unit
4.
13
The following procedure describes how to
use
the
MSU to gain access
to
a desired
station
in
an MJU network for
test
purposes.
(1)
Insert
the
TRMT and
RCV
cord reel plugs
into the appropriate
jacks
in
the
testboard
associated with
the
desired channel.
(2) Depress SIG key
and
the
lamp
under
the
key will light.
(3) Depress
the
desired BRANCH key(s),
in
the
proper order, required to reach
the
desired
station. The MSU display will show each
BR
number and HUB ID code
as
they
are
received.
ISS
2,
SECTION
666-600-101
The
transmitter
DTS
IDLE
CODE
key
should
not
be
depressed
and
the
BYTE
ENCODER
switches
should
not
display
the
idle code
byte
(01111110
or
11111110)
before
or
during
the
following
steps.
(4)
Depress TST key
and
the
lamp
under
the
key will light.
Note:
If
a mistake is made while performing
Steps
(2)
through (
4)
above, depress
the
CLR
key
and
start
again.
(5)
Tests
can
now be
performed
using
the
KS-20908
and
KS-20909 DTSs.
(6)
At
the
conclusion
of
testing, depress
the
CLR
key and
the
lamp
under
the
key will
light
for approximately one-half second.
If
the
SIG
or
TST lamps under
the
keys
are
lighted
when
the
CLR key
is
depressed,
they
will
extinguish.
If
the
SIG
or
TST
lamps
under
the
keys were lighted
prior
to
the
CLR key being
depressed
but
were extinguished when
the
CLR
key was depressed,
they
will
remain
extinguished
and
the
MSU
will automatically go into
the
test
mode.
(7) After
the
CLR
lamp
extinguishes, remove
the
TRMT and
RCV
cord reel plugs from
the
testboard jacks.
Note:
If
the
TRMT
and
RCV cord reel
plugs
are
removed from
the
jacks before
the
CLR key is depressed,
the
CLR
lamp
will
flash. The CLR
lamp
will extinguish
after
the
TRMT
and
RCV cord reel plugs
are
reinserted into
the
jacks. Testing can
then
be continued
or
the
channel can be
returned
to normal by performing Steps
(6)
and
(7)
above.
Control
and
Test Codes
4.14
When using the control code
generator
and
test
code generator
to
send codes:
(1)
Set
the
CONT CODE switch to
the
desired
position.
Caution:
Verify
that
customer
data
is
not
being
transmitted
over
the
channel
to
be
tested
by
monitoring
the
channel
with
the
receiver
as
follows:
Plug
the
receiver
cord
reel
Page
19

SECTION
666-600-101
plug
into
the
appropriate
MON
jack.
If
receiver
BYTE
PATTERN
LED
8
is
lighted
and
LEDs
2
through
7
are
dimly
lit,
customer
data
is
being
sent
over
that
channel.
Notify
customers
at
both
stations
that
tests
are
about
to
be
performed
and
obtain
customer
permission
to
test
the
channel.
If
permission
is
granted,
inform
the
customer
that
data
should
not
be
transmitted
until
further
notice.
When
receiver
BYTE
PATTERN
LED
8
is
extinguished,
continue
with
the
test.
(2)
If
the
TEST CODE (00011100) is to be
transmitted,
insert
one of
the
test
code cord
reel plugs into
the
appropriate
jack
labeled
TO
NEAR
or
TO
FAR.
If
a control code is to be
transmitted, select
the
appropriate control code
and
insert
one of
the
control code cord reel
plugs into
the
appropriate
jack
labeled
TO
NEAR
or
TO
FAR.
(3) After completing all tests, remove
the
cord
reel plug from
the
jack
and
notify
the
customer
that
data
transmission
can
be
resumed.
Dummy and Signal
Plugs
4.15
Dummy plugs
are
used to open the channel
lines
at
the
testboard. The plugs can be
inserted into any of
the
top four jacks in a
jack
module when a channel is being tested.
4.16
A signal plug is used for priority circuits.
It
covers
the
top four jacks of a jack module
and
prevents plugs from being inserted into
the
jacks
and
interrupting
service on
the
channel lines.
Clock
Circuit
Check
Check
the
clock
failure lamp,
located
above the clock switch, and for presence
of
clock
signals
on both
lines
DAILY.
4.17
The lamp should be extinguished when
the
switch is
in
position A
or
B.
The lamp
Page
20
should be lighted when
the
switch is in
the
middle
position.
If
the
lamp does
not
light
when
the
switch is
in
the
middle position,
it
should be replaced
according to Section 666-600-301.
Using
the
TRK
FAIL
ACO Key
4.18
When the TRK FAIL
ACO
key is operated,
the
CO
service
alarm
is
not
activated by a
trunk
failure monitored by
the
TFD
and
the
TRK
FAIL
ACO
lamp is lighted.
Using
the
TST
BD
F/PWR
UN
FAIL
ACO Key
4.19
When
the
TST
BD
F
/PWR
UN
FAIL
ACO
key is operated,
the
CO
service
alarm
is
not
activated by a testboard fuse
or
power
unit
failure
and
the
TST
BD
F
/PWR
UN
FAIL
ACO
lamp
is
lighted.
5.
REFERENCES
5.01 This
part
contains lists
of
Bell
System
Practices (BSPs), schematic drawings (SDs),
and
circuit descriptions (CDs)
that
pertain
to
the
equipment
and
apparatus
in the 950B testboard.
5.02 For more detailed information on the testboard,
refer to
the
following:
NUMBER
TITLE
CD-
& SD-73076-01 KS-20908
Data
Test
Set
CD- & SD-73077
-01
KS-20909
Data
Test
Set
CD-
& SD-73085-01 950-Type Testboard
CD- & SD-73102-01 Digital Signaling
Test
Unit
CD- & SD-99609-01 LocalMaintenanceCenterDisplay
Circuit [Trunk
Failure
Display
(TFD)]
SD-69513-01 400D Key Telephone
Unit
SD-69559-01 416A Key Telephone
Unit
This manual suits for next models
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