Bell 103A User manual
BELL
SYSTEM
PRACTICES
Plant Series
SECTION
591-014-100
Issue 5,
January
1961
AT&TCo Standard
DATA
SET
l03A
TYPE
IDENTIFICATION
AND
OPERATION
1.
GENERAL
1.01
This sectio;n includes identification
and
op-
eration
of
Data
Set
103A type
(Fig.
1
and
2).
It
does
not
include
information
related
to
business machines used
with
this
type
data
set.
1.02
This
section is reissued
to
include
informa-
tion concerning
the
D35C-61
cord
which
replaces
the
D25C-61
cord
which is
Manufacture
Discontinue
(MD).
Since
there
are
data
sets
using
the
D25C-61 cord,
information
concerning
this
cord
and
its
uses will be
retained
in
this
section.
1.03
Data
Set
103A
type
was
designed
to
simul-
taneously
transmit
and
receive low-speed
serial
data
at
rates
up
to
300
bauds
in
DATA-
PHONE*
service over
the
voice message switched
\
8-3/4
IN.
----\
-r-
network,
or
at
rates
up
to
150
bauds
in
TWX
service over
teletypewriter
exchange
type
facili-
ties.
*Service
Mark
of
the
American
Telephone
and
Telegraph
Company
(1)
Data
Set
103A1 is used -
• with customer-provided business
machine
or
computer-type
terminals
at
TWX-CE
stations,
• with customer-provided business
machine
or
computer-type
terminals
at
DATA-
PHONE
service
stations
in
systems
pro-
viding communications
with
3-row tele-
typewriter
equipment.
II
IN.
-------~
Fig. 1 - Data
Set
103A Type and Data
Auxiliary
Set
804B1
©American
Telephone
and
Telegraph
Company, 1967
Printed
in
U.S.A. Page 1
SECTION
591-014
..
100
Fig. 2 - Data
Set
103A Type and 567PB-61 Telephone
Set
(Manufacture Discontinue)
(2)
Data
Set
103A2 is
used-
•
with
customer-provided business machine
and
computer-type
terminals
at
DATA-
PHONE
service
stations,
but
•
not
with
customer-provided business
ma-
chine
or
computer-type
terminals
at
DA
TA-PHONE
service
stations
in
systems
providing
communications
with 3-row tele-
typewriters.
1.04 A
Data
Auxiliary
Set
804B1
(Fig.
1)
or
567PB-61 Telephone
Set
(MD)
(Fig.
2) is
required
for
external
control
of
the
data
set
and
for
establishing
the
data
set
transmission
path.
The
data
auxiliary
set
or
telephone
set
may
be
arranged
either
for
voice
communication
on
DDD
or
for
call
progress
tone
monitoring
only
on
TWX.
1.05
Data
transmission
is accomplished over
two
frequency
shift
channels.
The
fre-
quency
channel
used
by
each
station
during
a
connection is
determined
by
the
station
that
originates
the
call
(Table
A).
2.
DESCRIPTION
2.01
Transmission
output
level options
and
dis-
connect options
are
provided by
the
strap-
ping
arrangement
of
TB1
(Fig.
3).
TABLE
A
FREQUENCIES
FREQUENCY
(Hd
STATION
SIGNAL
MODE
TRANSMITTED
DATA
SET
DATA
SET
lO3Al lO3A2
Originating
fl
mark
(f
1m
) 1070 1270
fl
space
(f
1s
) 1270 1070
Answering
f2
mark
(f
2m
) 2025 2225
f2
space
(f
28
) 2225 2025
Page 2
ISS
5, SECTION
591-014-100
Fig. 3 - Data
Set
103A Type,
Top
View, Cover Removed
2.02
Components
of
Data
Set
103A
type
are
enclosed in a two-tone
gray
plastic
covl.~red
case.
The
cover is heI
rl
in
place by
four
retaining
screws
in
the
base
(Fig.
4).
See
the
section en-
titled
Data
Set
103A
Type,
Maintenance
(591-014-300)
for
cover
removal
and
replacement.
2.03
Data
signals
at
th(~
data
set
interface
are
EIA
StaHdard
HS-2;;;2-A
(bipolar)
type.
2.04
Data
Set
Im~A
type
with
Data
Auxiliary
Set
804Bl
or
i')()7PB-61
Telephone
Set
(MD) is used
for
connection
to
a 2-wire
central
Page 3
SECTION
591-014-100
CONNECTOR
KS-19087,
L2
(P4)
(TO CUSTOMER
SUPPLIED
CORD)
KS-19088,
L2
(P5)
(TO
D25C
-
61
CORD
OR
D35C-61
CORD)
RETAINING
SCREW
Fig.
4 - Data
Set
103A Type,
Rear
View
office
or
PBX
line.
The
data
auxiliary
set
or
telephone
set
is used
to
control
the
functions
of
the
data
set.
2.05 A block
diagram
of
the
Data
Set
l03A
type
is
shown
in
Fig.
5.
It
illustrates
the
five basic
component
sections of
the
data
set
which
are:
•
Modulator
-
Data
transmitter
•
Demodulator
-
Data
receiver
•
Control
-Logic
and
timing
circuitry
• Line
circuit
-
Impedance-matching
trans-
former
and
ringing
detector
•
Power
supply
-Recti
fie
r
-+- 2.06 A
35-conductor
5-1/2
foot D35C-61
cord
-+-
for
connecting
telephone
circuits
to
data
set,
and
a
3-conductor
lO-foot
power
cord
KS-14532,
List
15
are
supplied
with
the
Data
Set
103A type.
Page
4
2.07 A 25-pin
connector
(KS-19087,
List
2) is
provided
at
the
rear
of
the
data
set
for
connecting
the
business machine.
This
connec-
tion is
made
with
a
customer-furnished
c'lble.
In-
terface
leads
present
at
this
connector
are
num-
bered
and
designated
as
shown
in
Table
B.
2.08
The
Data
Auxiliary
Set
804Bl
is equipped
with
a D30C-61
5-1/2
foot
cord.
The
567PB-61 Telephone
Set
(MD) is equipped
with
a
D50J
-61
5-1/2
foot
cord.
2.09
The
data
auxiliary
set
is equipped
with
a
589AG key.
The
567PB-61
Telephone
Set
(lVID)
is equipped
with
a 589AC key.
Designa-
tions
and·
functions
of
these
keys
are
shown
in
Table
C.
2.10
The
transmit
levels
of
both
the
low-fre-
quency
(originate)
channel
and
the
high-
frequency
(answer)
channel
can
be
individually
adjusted
by
rearranging
spade-tipped
straps
on
terminal
strip
TBI
in
the
data
set
(Fig.
3).
Strapping
information
can
be
found
in
Section
TELEPHONE
LINE
KEYS AND
TELEPHONE
~
MODULATOR
~
CIRCUIT
CONTROL
AND
TEST
LINE
CIRCUITS
CIRCUIT
r---
FILTER
DEMODULATOR
~
POWER
SUPPLY
-
~
ISS
5,
SECTION
591-014-100
RING INDICATOR
DATA SET READY
DATA
TERMINAL
READY
CLEAR
TO
SEND
DATA CARRIER DETECTOR
TRANSMITTED
DATA
RECEIVED
DATA
+
20
VOLT
INTE
RFACE
ECTOR
CONN
CE
"'
22
CC
"'
6
CD
./
20
CB
" 5
CF
"'
8
SA " 2
BS
./
"'
3
+P
9
CUSTOMER
EQUIPMENT
> -
20
VOLT
-P
~-----+~.------------------~<
10
SIGNAL GROUND AS
111---+-----------------<
7
PROTECTIVE GROUND
AA
Fig. 5 - Data Set 103A Type, Block Diagram
591-014-200.
This
feature
enables
compromise
equalization
of
the
transmitted
data
signals.
3.
OPERATION
ATTENDED
STATION
OPERATION
3.01
The
transmission
path
for
the
originating
station
data
set
is
established
by
first
de-
pressing
the
TALK
button
on
the
associated
tele-
phone
set
or
data
auxiliary
set
and
placing
the
call
in
the
usual
telephone
manner.
3.02
At
the
answering
station,
ringing
current
will
cause
the
bell
to
ring
and
operate
cir-
cuitry
in
the
data
set
to
signal
the
business
machine
that
there
is
an
incoming
call.
It
also
prepares
the
data
set
for
the
answering
mode.
After
at
least
one
complete
ringing
cycle,
the
attendant
at
the
answering
station
should
de-
Page
5
SECTION
591-014-100
TABLE
B
INTERFACE
LEAD
DESIGNATIONS
PIN NO.
LEAD
AND FUNCTION DESIGNATION
1
PROTECTIVE
GROUND -Common to
signal
and
ac
power
service
ground
AA
2
TRANSMITTED
DATA
-
Customer
data
presented
to
data
set
BA
3
RECEIVED
DATA
-
Data
output
presented
to
business
machine
BE
5
CLEAR
TO
SEND
-
Signals
business machine
tha
t
da
ta
may
be
trans-
CB
mitted
--
6
DATA
SET
READY
-
Signals
business machine when
data
set
is
in
the
CC
data
mode
7
SIGNAL
GROUND -Common· to
frame
ground
and
ac
power
service AB
ground
8
DATA
CARRIER
DETECTOR-
Signals
business
machine
that
data
car-
CF
riel' is being received.
9
+POWER
-
Power
supply
(+20
volts)
+P
10
-POWER
-
Power
supply
(-20
volts)
-P
20
DATA
TERMINAL
READY
-Business machine applies on ON condition
for
auto
answer
and
an
OFF
condition
to
CD
disconnect
data
set
from
the
line
22
RING
INDICA
TOR
-
Indicates
presence
of
ringing
current
to
business
CE
machine
on incoming
calls
press
the
TALK
button
and
lift
the
handset
to
trip
ringing
and
place
the
data
set
in
the
answer
mode.
If
voice
communication
option is provided,
the
attendant
may
stay
in
the
talk
mode
to
con-
duct
voice
communication
or
go to
the
data
mode
by
depressing
the
DATA
button.
3.04
At
the
end
of
the
1-1/2
second
SF
guard
interval,
the
answering
station
will
transmit
an
f2
mark
tone to disable echo
suppressors
on
toll
trunks.
Echo
suppressors
will
remain
disabled
as
long
as
any
tones
are
being
transmitted.
3.03
When
the
answering
station
DATA
button
is depressed
and
released,
the
TALK
but-
ton
is
automatically
released
and
a
timing
inter-
val
of
1-1/2
seconds is
initiated.
This
timing
interval
is
the
single-frequency
(SF)
guard
interval.
The
purpose
of
this
guard
interval
is
to
insure
the
receipt
of
an
off-hook
signal
by
the
originating
(serving) office
from
the
ans-
wering
station.
Page
6
3.05
When
the
originating
station
attendant
hears
this
f2
mark
tone,
the
attendant
should
depress
the
DATA
button
until
the
DATA
lamp
lights.
When
the
DATA
lamp
li~hts,
the
DATA
button
should
be released. Release
of
the
DATA
button
causes
the
following to
occur
in
the
sequence
listed:
(1)
TALK
button
releases
(2)
Starts
a 1-1/2 second
timing
interval
ISS
5,
SECTION
591-014-100
TABLE
C
KEY
ASSIGNMENTS
KEY
NUMBER
KEY
ILLUMINATED
DESIGNATION
DATA
AUX
567PB-61 FUNCTION
KEY
SET
804B1
TEL
SET
AUTO 1 6 A locking key used
to
provide
automatic
Yes
answer
of
incoming
calls
A locking key used
to
connect
send
and
LOCAL 2 5 receive
leads
together
and
disconnect
data
No
set.
This
permits
local
operation·
and
test
of
business
machine.
--
TEST
2 3 4 Nonlocking key used
to
test
data
set
under
No
the
direction
of
data
test
center
TEST
1 4 3 Nonlocking key used
to
test
data
set
under
Yes
the
direction
of
data
test
center
TALK
5 2 Locking key used to connect telephone
set
to
No
data
line
Nonlocking key used
to
shift
from
talk
to
DATA
6 1
data
mode (also
takes
data
set
out
of
test
Yes
mode
if
connected
in
error)
(3)
Transmits
fl
mark
tone
to
answering
station
(1)
AUTO
button
is depressed
(alternate
auto
.,
or
manual
answering
option).
(4)
Signals
business machine
at
originate
end,
over
the
CB
interface
lead,
that
data
con-
nection is completed
3.06 Upon
receipt
of
fl
mark
tone
at
the
answering
station,
the
station
signals
its
business
machine
over
the
CB
interface
lead
that
the
data
connection
has
been completed.
Data
transmission
can
now begin.
3.07
For
a
more
detailed
description
of
data
set
operation, see CD-
and
SD-1D034-01.
AUTOMATIC
ANSWER
3.08
Calls
may
be
answered
automatically
when
either
of
the
following options
are
provided:
(2)
Strapping
option is connected
to
provide
permanent
automatic
answering
on
all
incoming
calls
(permanent
automatic
answer-
ing
option).
Use
of
this
option bypasses
the
AUTO button.. .J
3.09
With
the
set
arranged
for
automatic
answer,
ringing
current
will
cause
the
bell in
the
telephone
set
to
ring
and
a
relay
in
the
data
set
to
operate.
Operation
of
this
relay
trips
ringing
and
causes
the
data
set
to
change
to
the
off-hook condition,
providing
an
ON condition is
present
on
the
CD lead.
Under
these
conditions,
the
line
control
circuit
will
initiate
the
1-1/2
second
SF
guard
interval.
From
this
point,
the
call
will
progress
as
previously described
in
3.05
and
3.06.
Page 7
SECTION
591.014.100
DISCONNECT
3.10 The connection
may
be
terminated
at
the
end
of
transmission by one
of
the
follow-
ing
options:
Automatic
(1)
With
INITIATE
DISCONNECT option
enabled: The
station
that
is
initiating
dis-
connect
must
momenta'rily apply
an
OFF
con-
dition to
the
CD
lead. This causes
the
data
set
to
transmit
a 3-second
burst
of
spacing
tone. The frequency
of
the
ft space tone is
1270 Hz
for
Data
Set
103A1 and 1070 Hz
for
Data
Set
103A2 when
acting
as
an
originate
station.
The frequency
of
the
f2
space tone
is 2225 Hz
for
the
Data
Set
103A1
and
2025 Hz
for
Data
Set
103A2 when acting
as
an
answer
Page 8
8 Pages
station.
After
transnlission
of
this spacing
tone,
the
station
will go to
the
on-hook con-
dition. Should
the
distant
station
be
arranged
for
RESPOND TO DISCONNECT option,
it
will recognize
the
space frequency
signal
for
1-1/2
seconds, disconnect
from
the
line,
and
go
to
the
on-hook condition.
(2) Without
INITIATE
DISCONNECT op-
tion:
An
OFF
condition on the
CD
lead
will cause
station
to disconnect
and
go to
the
on-hook condition immediately.
Manual
Both
attendants
must
lift
handset, depress
TALK
button
(this changes the
data
set
from
the
data
mode to the
talk
mode),
and
restore
handset
to on-hook condition.
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