Line Sase Positions Maximum*
Number
A S (
of Lines SiS I SiS I ! SiS I
sis I sis I --- SIS I siS I SiS II SiS I siS I Sync IA
176 SiS I sis I Sync IS Sis I SIS I Sync IIA SiS I SiS II Sis II
sis I Sync I A Sync IA 136 Sis I siS II Sync IA Sis I SiS II Sync IS ;28 SiS I Sync IS Sync IA
siS I Sync IA Sync IIA 124 SIS I Sync IS Sync IS 120 siS I Sync IS Sync IIA 116
sis I SIS II ---
sis I --- Sync IA 112
Sis I Sync II A Sync IIA
sis I --- Sync IS 104 sis I --- Sync IIA 100 sis I ------88
sis II SIS II siS II
sis II siS II Sync IA 72
sis II Sync I A Sync IA
sis II sis II Sync IS 64 siS II Sync IS Sync IA SiS II SiS II Sync rrA
sis II Sync IA Sync IIA 60 SIS II Sync IS Sync IS 56 SIS II Sync IS Sync IIA 52
siS II SIS II ---
--- Sync I A Sync IA siS II --- Sync IA
48
siS II Sync IIA Sync nA SiS II --- Sync IS 40 --- Sync IS Sync IA
Sis II --- Sync IrA
--- Sync IA Sync IIA
36
--- Sync IS Sync IS 32
--- --- Sync IA SIS II ------24
--- Sync II A Sync IIA
--- --- Sync IS 16
--- --- Sync IIA 12
Figure 8. Line Base Configurations
LEGEND SISI - Start-Stop Sase Type I (88 Max lines) siS II -Start-Stop Sase Type II (24 Max lines) Sync I A -Synchronous Base Type I A (24 Max lines) Sync I B -Synchronous Sase Type [B (16 Max lines)
Sync IIA -Synchronous Base Type IIA (12 Max lines)
Notes: I. The maximum total Start-Stop type bases is three,
while for the synchronous bases it is two. However,
the combined maximum total is three.
2. The line base types shown in this chart are assigned
by the base position (A, B or () to conform with ordering
procedures as follows:
A-F irst SiS bose.
B-Second SiS base, or Second Sync base.
(-Third sis base, or First Sync base.
* This maximum may be decreased when a 2712 Attachment or
the Sync (lock feature is attached to the 2703. Th is decrease
occurs whenever any 2712 Expander feature is installed, and
is as follows:
---Modell Expander -each of these features decreases the
maximum available I ines by six (6).
---Model 2 Expander -each of these features decreases the
maximum available lines by two (2).
37

Table 1. Line Sets Per Line Base and Per 2703. FEATURE NAME per Sis per SIS per Sync Base Type per 2703 Base Base
Type I Type II 1A 1B 2A
Data Line Set (inc!. expanders) 11 (5 exp.) 3 (1 exp.) -
- - 22 (10 exp.)
Telegraph Line Set (inc!. expo )* 11 (5 exp.) 3 (1 exp.) ---22 (10 exp.)
IBM Line Set IA 9 3 ---12
IBM Line Set IB 9 3 ---12
IBM Line Set 2 4 3
- - - I 4
2712 Modell Adapter (incl. expo ) 8 (4 exp.) 3 (or 2 and 1 exp.)
- - -
8 (4 exp.)
2712 !vlodel 2 Adapter (incl. expo ) 8 (4 exp.) 3 (or 2 and 1 exp.) I - I - I - I 8 (4 exp.) I Sync Line Set Sync Line Set with Sync Clock
speed operates al11ines of that speed within anyone 2703. The speed options available are: 45.5 bps, 50 bps, 56.9 bps, 74.2 bps, 100 bps, 110 bps, 134.5
bps, and 600 bps.
2712 Modell and Model:? Adapter Features
The 2712 Adapter features, when used in conjunction
with an IBM 2712 Remote Multiplexer, provide for
concentration of a number of low-speed lines over
one voice-grade (high-speed) line. Figure 9 shows
a typical Gonfiguration. Half-duplex low-speed lines
are brought into the 2712 Remote Multiplexer, which
bit-multiplexes data from the terminals onto a full­
duplex voice-grade line. The data is separated
at the 2703 and fed into the individual 2712 Adapters
in the 2703. Data going to the terminals is multiplexed at the 2703 by the 2712 Adapter and sent over the other
half of the full-duplex voice-grade line. The remote
2712 separates the data and sends it to th terminals
over the lower speed lines. To the CPU it appears
to be working with a number of low-speed lines.
Thus, no programming changes are required.
Two models of this feature are available. Model 1
operates with up to 10 lines (using a Modell
Expander feature to provide for lines 9 and 10) at
* includes W. T. single current and double current line sets
38
6 4 3 12
3 <) - D. U v
speeds of 134.5 bps. This model permits attachment
of such terminals as the 1050, 1060, 2740, and 2741.
Model 2 operates at 74. 2 bps with WU Plan 115A,
AT&T 83B2, or AT&T 83B3 line control (Model 28
teletypewriter terminal) and can have up to 14 lines
(using a Model 2 Expander feature to provide for
lines 9 to 14). A block of eight addresses must be
assigned for each expander, as well as for each
adapter feature. However, the 1\lodel 1 Expander
utilizes only two of the eight assigned addresses,
while the Model 2 Expander utilizes six of the eight
assigned addresses.
Figure 10 shows the various configurations using
the 2712 Model 1 and Model 2 Adapter features (with
the Expander features) on the 2703 with maximum
lines for each configuration. There can be a max­
imum of four expanded 2712 Adapter features (any
combination) on one 2703. NOTE: The 2712 Attachment feature is required for installa­
tion of either the 2712 Modell or Model 2 /\dapter. Modell requires a Type 3002 with C2 conditioning
full-duplex private-line data channel, while the
Model 2 requires a Type 3002 with C 1 conditioning
full-duplex private-line data channe 1. The 2703 is
connected to the communications channel \'ia Western Electric Data Set 202D2 or equivalent. I