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Introduction
Manufacturing facility management’s need to reduce oper­
ating cost through more immediate awareness of the status
of plant operations is increasing. The IBM 2790 Data Com-
| munication System (Figure 1) is a two-way data communi­
cation and production reporting system. It is a highly
flexible two-way data communication system designed to
meet the expanding requirements for in-plant data commu-
| nications and production monitoring. The 2790 system
provides for rapid transfer of information from various area
stations (AS’s) and data entry units (DEU’s) to a central
computer for recording, processing, and analyzing.
The AS’s accept alphameric data from standard
80-column punched cards; they accept numeric data from
punched identification badges and manual entry units. The
DEU’s accept ten positions of numeric data from punched
| cards or punched badges; they also accept information from
manual entry units. The AS and DEU information is trans­
mitted by area stations to a transmission control unit
(system controller). The transmission control unit (TCU)
communicates with an IBM System/360 via a local (multi­
plexer channel) or a remote (binary synchronous trans­
mission line) attachment.
Either an IBM 2715 Transmission Control Unit or an
IBM 1800 Data Acquisition and Control System with an
1800/2790 Adapter may be used as the system controller
for the 2790 system. For further information about the
IBM 1800 performing as the system controller, see Systems
Reference Library manual,
IBM 1800 Data Acquisition and
Control System Functional Characteristics , GA26-5918-7,
with TNL N26-0241, or a later version.
The IBM 2790 system configuration consists of a central
processor (IBM System/360), a transmission control unit
(IBM 2715), area stations (IBM 2791 or IBM 2793), data
entry units (IBM 2795 or IBM 2796), and other I/O devices.
The 2790 system configuration consists of as many as 100
AS’s connected in a loop configuration, starting and ending
at the TCU. Adjacent units of the 2790 Data Communi­
cation System are connected by a twisted-pair cable (except
the IBM 1035 Badge Reader and IBM 1053 Printer which
attach to the area station by multiwire cable). For example,
the units may be installed at intervals of 1000 feet by using
#22 AWG twisted-pair wire, or up to 4500 feet by using
RG 130/21 coaxial cable (Figure 2). DEU’s can be attached
to an AS. Connection between a DEU and an AS is estab-
Data Entry Units
Figure 1. A Typical IBM 2790 Data Communication System
Introduction 5