APPENDIX B. COMMUNICATIONS FACILITIES
The 2703 operates in half-duplex mode over: • Common-carrier switched telephone network. • Common-carrier switched 150-baud Teletype­
writer Exchange (TWX) network • Common-carrier leased private-line telephone
service • Common-carrier leased private-line telegraph
service
a. Common-carrier Type 1002 and 1005 pri vate-line service
b. 150-baud Type 1006 pri vate -line service • Western Union Type 3002 channels with C1
conditioning • Western Union Type 3002 channels with C2
conditioning • World Trade Common-Carrier Private Line
Telegraph Circuits (Single Current and/or
Double Current) • Equivalent privately owned communications
facilities COMMON -CARRIER - PROVIDED FACILITIES
Common-Carrier Switched Telephone Network
1. At 134. 5 bps, a Western Electric Data Set 103A2* is required for each line equipped to
answer calls from asynchronous terminal
devices.
2. At 1200 bps, a Western Electric Data Set 202C1, * or a combination of a 202D1 * with a
Data Auxiliary Set 804A1, * is required for
each line equipped to answer calls from synch­
ronous terminal devices.
3. At 2000 bps, a Western Electric Data Set 201A3* is required for each line equipped to
answer calls from synchronous terminal
devices.
4. For each line arranged to automatically ori­
ginate calls, a Western Electric Automatic
Calling Unit 801A1 * or 801C2* is required in
addition to the data sets in items 1, 2, and 3. 5. For World Trade switched networks operating
at bit rates up to 600 bps, an IBM 3976 Model
2 is required.
6. For Binary Synchronous Communications at
speeds of 600 or 1200 bps on World Trade
*or equivalent
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switched networks, each line requires one
of the following:
a. IBM 3976 Model 3 Modem for use in
countries where approved.
b. GPO Date 1 1 1\Todel 5 for use in the
United Kingdom.
c. PTT D1200S (GH 2011 Model 5) for
use in Germany.
d. PTT GH 2002A for use in Sweden. NOTE: Automatic answering is available on each of the data
sets above.
Common-Carrier Switched Teletypewriter Exchange (TWX) Networks
1. For communications with common-carrier TWX stations (Model 33/35 type) at 110 bps,
a Western Electric Data Auxiliary Set 811B1 *
is required on each line equipped to answer
calls. NOTE: A common-carrier TWX station must be provided with the
first 811B1* unit ;t each site.
2. For communications with start/stop terminal
devices at 134.5 bps, a Western Electric Data Set 103A1 * is required on each line equipped
to answer calls.
3. In items 1 and 2 preceding, on lines equipped
to automatically originate calls, a Western Electric Automatic Calling Unit 801A1/ A6* or
801C2/C4* is also required for'each line.
Common-Carrier Leased Private-Line Telephone Service 1. At 134.5 bps, either a suitable IBM Line
Adapter, an IBM 2711 Line Adapter Unit equipped with a suitable IBM Line Adapter, or
a Western Electric Data Set 103F2* is required
for each line (see "Note"). World Trade
requires the IBM 3976 Modell modem.
2. At 600 bps (start/stop four-wire), either a 2711
equipped with a suitable IBM Line Adapter or
a Western Electric Data Set 202D1 * is required
for each line (see "Note"). World Trade
requires either an IBM 3976 Model 3 or an IBM
3977 Modell or 2.
3. When connecting to a 2712 Remote Multiplexer
Modell, a four-wire full-duplex Type 3002 Pri vate- Line Service with C2 conditioning and
a Western Electric Data Set 202D2* are re­
quired; when connecting to a 2712 1\Todel 2, a

four-wire full-duplex Type 3002 Private-Line Service with C1 conditioning and a Western
Electric Data Set 202D2 * are required. In
either case, alternate voice-data capability
with key-controlled ringing is recommended.
The Data Set 202D2* must be wired and equipped
by the local common carrier to provide full­
duplex data operation and a one-way, low-speed
reverse channel to accommodate signals trans­
mitted from the 2703 to the 2712. This wiring
arrangement must be ordered by the customer
at the time he places his data set order. NOTE: Where the line conforms to the specifications in the SRL manual A24-,:\435** for Limited-Distance Line Adapter Type
1, the IBM Line Set 1A (#4686) or 1B (#4687) can be used in
place of a data set for attachment of 2740 or 2741 terminals. \Vhere the line conforms to specifications in the cited manual
for Limited-Distance Line Adapter Type 2, the IBM Line Set 2 (#4688) can be used to attach IBM 1030, 1050, 1060, 1070, 2740, and 2741 systems and terminals.
4. For each line servicing synchronous term ina I
devices, the following is required;
a. At 1200 bps (synchronous), a Western
Electric Data Set 202D1 * is required.
b. At 2000 bps, a Western Electric Data Set 201A3* and Type 3002 Private-Line Service with C2 conditioning or better
are reqUired.
c. At 2400 bps, a Western Electric Data Set 201B1 * and Type 3002 Private-Line Ser­ vice with C2 conditioning or better are re­
quired. For operation at 2400 bps using
Western Electric Data Set 201Bl * on Type 3002 Private-Line Service with C2 condi­
tioning, there are additional restrictions
and limitations to the facility and opera­
tions. See the SRL manual, General In­
formation--Binary Synchronous Communi-· cations, Form A27 -3004, for details. 3004, for details.
d. At 4800 bps, Modems may be attached by
the customer under the provisions of the
'Mult.i.ple Supplier System Policy'; con­
sult your IBM Marketing Representative.
5. For each ',;orld Trade line servicing synchro­
nous terminal devices, one of the following
is required: '" or equivalent "'* Form .\24-3435-2, or subsequent revisions a, IBM Modems--At 600 or 1200 bps, an IBM
3976 Model 3 or an IBM 3977 Model 1 or
2 is required. At.speeds up to 2400 bps
(bit rate must match clock feature), an
IBM 3977 Model 2 is required.
b. PTT Modems--At 600 or 1200 bps, the United Kingdom uses GPO Datel 1 Model
5, Germany uses PTT D1200S (GH-2011
Model 5), and Sweden uses PTT GH- 2002B and PTT GH-2002C.
c, At 4800 bps, consult the appropriate IBM
Teleprocessing Coordinator for Modem
information.
d. NTT Modem--At 600 or 1200 bps, Japan
uses NTT Modem DT1203.
Common-Carrier Leased Private-Line Telegraph Service 1. On common-carrier Type 1002 or 1005 private­
line service, common-carrier data sets are
not required. However, a 62. 5-milliampere
neutral dc loop must be provided by the com­
mon carrier for each telegraph channel where
operation is via Te legraph Line Set (#7897)
2. On common-carrier 150-baud Type 1006 pri­
vate-line service, appropriate channel termi­
nation must be provided by the common carrier.
Western Union TyPe 3002 Channels with C1 Condi­
tioning
1. An IBM Line Adapter (#4639 for two-wile, or
#4647 for four-wire) on a 2711 Line Adapter Unit is required for each start/stop channel
termination. For operation at 1200 bps (syn­
chronous), a Western Electric Data Set 202D1*
is required for each channel termination.
Western Union Type 3002 Channels with C2 Condi­
tioning
1. At 2400 bps, a Western Electric Data Set 201B1 * is required for each line servicing
synchronous terminals.
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