Data Line Set Expander. Permits attachment of up
to eight additional lines to the Data Line Set feature.
IBM Line Set 1A. Allows attachment to the 2703 of
up to eight half-duplex lines with 2740/2741 terminals.
Used for two-wire local use (up to 4.75 wire miles).
IBM Line Set lB. Allows attachment to the 2703 of up
to eight half-duplex lines with 2740/2741 terminals.
Used for four-wire local use (up to 4.75 wire miles).
IBM Line Set 2. Allows attachment to the 2703 of up
to eight half-duplex lines with IBM 1030's, 1050's,
1060's, 1070's, 2740's or 2741 'so Used for two-wire
local use (up to 8 wire miles).
Telegraph Line Set. Allows attachment of up to eight
lines via common-carrier private-line telegraph
service--such as Telephone Company Type 1002
(45.5 and 56.9 bps) and Type 1005 (74.2 bps) Private-
Line Service, and Western Union Class A, B, and C
Channels. AT&T 83B2/83B3 and Western Union Plan
115A terminals at 75 bps and IBM 1050 or 2740
Model 2 terminals can be connected to the 2703 using
Telegraph Line Set Expander. Allows attachment of
up to eight additional lines to the Telegraph Line Set
Synchronous Line Set. Allows attachment of up to
four synchronous lines using voice-grade facilities.
Allows IBM 2701 's and IBM 2703's with System/360
processors, or System/360 Model 20 and IBM 1130's
with appropriate communications adapters, and IBM
2780's to be connected to the 2703.
Synchronous Clock. Required when attachment of
Western Electric Data Sets 202C1 or 202D1 are used.
Allows attachment to the 2703 of up to four such data
This group of features can be divided into five classi-
fications: (1) Line-Speed Options; (2) Auto Call;
(3) 2712 Attachments; (4) Two-Processor Attach-
ment; and (5) Isolation.
Line Speed Options. These features provide the
attachment of the various synchronous and asynchro-
nous terminals with the following speeds:
Autocall. Provides the 2703 with automatic dialing
capabilities for up to eight communications line
2712 Attachment Features. These include:
2712 Attachment--Needed for any 2712 lines.
2. 2712 Modell Adapter--Allows attachment of
up to eight 2712 Modell lines.
3. 2712 Modell Expander--Allows an additional
ninth and tenth line to the 2712 Modell Adapter
4. 2712 Model 2 Adapter--Allows attachment of
up to eight 2712 Model 2 lines.
5. 2712 Model 2 Expander--Allows an additional
ninth through fourteenth 2712 Model 2 line.
Two-Processor Switch Feature.
Enables the 2703 to
be physically attached to the multiplexer channels of
two System/360 processors. The 2703 must be in a
neutral state for the switching to occur. When in this
neutral state, the 2703 monitors both multiplexer
interfaces and automatically switches and locks to the
first channel addressing any line of the 2703. The
attached processor can return the switch to neutral
under program control or through a manual reset.
Isolation Control Unit. Allows power to be turned on
or off in the 2703 without generating spurious
C OMMUNIC A TIONS FACILITIES
Figures 1-2 and 1-3 show the
ties used with the 2702/2703, the data set used for
attachment of each terminal, the operating speed, and
As previously mentioned, the multiplexers appear as
control units to the IBM