IBM 2790 User manual

File No. 2790-09
Order No. GA27-3015-1
Systems Referen e Library
Component Des ription!
IBM 2730 Data Communi ation System
The IBM 2790 Data Communi ation System is a two-way ommuni ation
and produ tion reporting system. This publi ation des ribes the 2790
system units along with its apabilities, features, and appli ations. This
publi ation presumes a tele ommuni ations ba kground and IBM
System/360 experien e. The purpose of this publi ation is to assist
programmers and systems analysts in designing and operating the 2790
system.
This publi ation des ribes the 2790 system using the 2715 Transmission
Control Unit as the system ontroller. The IBM 1800 Data A quisition
and Control System, whi h ould also be used as the system ontroller,
is not des ribed in this manual. Information about the following units
is in luded in this publi ation:
IBM 2715 Transmission Control Unit IBM 2796 Data Entry Unit
IBM 2791 Area Station IBM 1035 Badge Reader
IBM 2793 Area Station IBM 1053 Printer
IBM 2795 Data Entry Unit
The following IBM publi ations are re ommended for use with this
manual:
IBM 35 7/1030/2 790 Badge Specifications, GA21 -9028
IBM System/360 Bib iography, GA22-6822
IBM Te eprocessing Bib iography, GA24-3089
IBM 2740 Communications Termina : Component Description,
GA24-3403
IBM 2740/2741 Communications Termina -Operator's Guide,
GA27-3001
IBM System/360 Operating System, Basic Te ecommunications
A ccess Method, GC 30-2004
IBM System/360 Disk Operating System, Basic Te ecommunications
Access Method, GC30-5001
IBM System/360 OS/DOS P anning for Improved BTAM Support o f
Remote BSC Stations, GC30-1005

Preface 2790 SRL Publications Availability Guide
This manual des ribes the IBM 2790 Data Communi ation
System with the IBM 2715 Transmission Control Unit as
the system ontroller. For information about the IBM
1800 system used as a system ontroller, see Systems Ref
eren e Library manual, IBM 1800 Data Acquisition and
Contro System Functiona Characteristics, GA26-5918-7
(with TNL N26-0241) or later edition.
Before using this manual, you should have a ba kground
in tele ommuni ations and experien e in using the IBM
System/360. This manual is designed for use as a ompre
hensive referen e manual by programmers and systems
analysts. Information about the following 2790 system
units is presented:
IBM 2715 Transmission Control Unit
IBM 2791 Area Station
IBM 2793 Area Station
IBM 2795 Data Entry Unit
IBM 2796 Data Entry Unit
IBM 1035 Badge Reader
IBM 1053 Printer
For information about programming the System/360
to operate with the 2790 system, see Systems Referen e
Library manuals: IBM System/360 Operating System,
Basic Te ecommunications Access Method, GC30-2004;
IBM System/360 Disk Operating System, Basic Te e
communications Access Method, GC30-5001; and IBM
System/360 OS/DOS for Improved BTAM Support o f
Remote BSC Stations, GC30-1005.
Manuals related to this publi ation are referen ed in the
Publi ations Availability Guide.
I
Second Edition (March 1970)
This is a major revision of, and obsoletes, G 27-3015-0. Significant new material
has been added throughout, and existing material has been changed extensively;
therefore, the entire manual should be reread.
Changes are periodically made to the information herein; any such changes will
be reported in subsequent revisions or Technical Newsletters.
This manual has been prepared by the IBM Systems Development Division, Publi
cations Center, Department E01, P.O. Box 12275, Research Triangle Park, North
Carolina 27709. form for reader’s comments is provided at the back of this
manual. If the form has been removed, comments may be sent to the above address.
©Copyright International Business Machines Corporation 1969, 1970

Contents
Introduction
Typical pplications ..............................
ttendance Recording ........................
Material Control ....................................
Production Control ..............................
Data Entry U n i t s
2795 Data Entry U n it ..............................
Badge-Card Reader ..............................
2795 Data E n t r y ..............................
Selection S w it c h ..............................
Phone J a c k ..........................................
Error Indicator/Reset Button .
Request L e v e r ....................................
2796 Data Entry U n it ..............................
2796 Data E n t r y ..............................
Data Entry Unit Transaction Selection .
Transaction Expansion ........................
Area S t a t io n s
2791 rea S tation ....................................
Transmission Capability .
Card Reader ..........................................
Badge R e a d e r ....................................
Transaction Selection Switches
Control K e y s ....................................
Manual E n t r y ....................................
Visual D isp la y ....................................
Operator Guidance Panel .
rea Station ddresses ........................
2791 Data E n t r y ..............................
dapters ................................................
2793 rea S ta tion ....................................
IBM 2715 Transmission Control Unit
2715 TCU F un ction s ..............................
Models of Operation with System/360
2715 Machine Features ..............................
Standard Features for Models 1 and 2
Selective Features for Models 1 and 2
Selective Features for 2715 Model 1 .
Selective Features for 2715 Model 2 .
Configuration Parameters .
2715 General Characteristics .
Multiplexer Channel dapter (Standard on
2715 Model 1 ) ...............................................................................31
C om m ands.................................................................................... 32
Binary Synchronous Communications dapter
(Standard on 2715 Model 2 ) .......................................................33
Real-Time Clock ( R T C ).............................................................35
Day Number .................................................................................... 35
CE/Operator P an el .............................................................................. 35
2790 d a p ter.....................................................................................39
Data-Handling C a p a c ity .............................................................39
2715 Operational Characteristics ...................................................... 40
Data Management ........................................................................ 40
Data Format.................................................................................... 41
2715 Control Requests .................................................................. 43
2790 ERP Message F o r m a t ...................................................... 53
Restart-Number L oggin g ............................................................ 54
Core Storage.................................................................................... 54
System/360 R e se t ........................................................................ 54
2715 Performance........................................................................54
Error P roced u res.............................................................................. 57
Error at the 2795/2796 Data Entry Unit or 1035
Badge R eader.................................................................................... 57
Error at the 2791 rea S t a t io n ................................................57
I
Length C h e c k ........................................................................57
Digit C heck.................................................................................... 58
Other 2790 Transmission Line Error Checks .... 58
Error at the Transmission Control U n it ...........................................58
2715 Error Recording .................................................................. 58
2715 D iagn ostics ........................................................................ 59
Multiplexer Channel Error Recovery Procedures . . . 59
Programming Considerations ............................................................ 61
System O peration...............................................................................61
OS and DOS S u p p ort...............................................................61
| User Job Planning F o rm s .................................................................. 62
rea Stations and Data Entry Unit Table (Figure 32) . . 62
Transaction Group Table (Figure 3 3 ) ..................................... 64
Transaction List Table (Figure 3 4 ) ........................................... 64
Glossary................................................................................................71
Index ........................ 73
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Illustrations
Figure Title
1 Typical 2790 Data Communications System .
I 2 IBM 2790 Configuration ................................................
3 IBM 2795 Data Entry U n i t ..........................................
4 IBM 2796 Data Entry U n i t ..........................................
| 5 DEU Badge and 80-Column Card Punch Information .
6 2795 Data Entry as ssembled in the 2715 TCU
7 2796 Data Entry as ssembled in the 2715 TCU
8 Segm entation..................................................................
9 IBM 2791 rea Station......................................................
10 cceptable rea Station Character Set and Card Code .
11 Operator P a n el...................................................................
| 12 Sample L e tterin g.............................................................
13 2791 Data Entry as ssembled in the 2715 TCU
14 IBM 1053 and 2740 Printer Character Set . . . .
15 Loop ttachment and Shift Register ..............................
16 IBM 2793 rea Station ......................................................
17 IBM 2715 Transmission Control U n i t ........................
18 Line Transfer S w itc h ......................................................
Figure Title Page
19 Line Transfer Switch-Third U nit..................................29
20 Point-to-Point Line Initialization Examples .... 33
1
21 Multipoint Line Initialization Examples........................34
22 CE/Operator P anel............................................................36
23 Transmission Line Utilization C hart ............................. 38
24 Transaction Control B y t e ................................................41
25 Message Format-System/360 to 2740/1053 . . . 43
26 Message Format- S or DEU to 1053 44
27 Control R e q u e sts ........................................................... 45
28 Example 2740 P r in to u t................................................47
29 Read Deferred Data and Reinitialize Disk Sequence . 51
30 Example 2740 Printout of an Unsoliciated Message . 53
31 Simplified Example of User T a b l e ..............................65
32 S and DEU Table F o rm ................................................66
33 Transaction Group Table F o r m ................................... 67
34 Translation List Table F o r m ......................................... 68
35 Data Entries........................................................................69
Page
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IV

Introduction
Manufa turing fa ility management’s need to redu e oper
ating ost through more immediate awareness of the status
of plant operations is in reasing. The IBM 2790 Data Com-
| muni ation System (Figure 1) is a two-way data ommuni
ation and produ tion reporting system. It is a highly
flexible two-way data ommuni ation system designed to
meet the expanding requirements for in-plant data ommu-
| ni ations and produ tion monitoring. The 2790 system
provides for rapid transfer of information from various area
stations (AS’s) and data entry units (DEU’s) to a entral
omputer for re ording, pro essing, and analyzing.
The AS’s a ept alphameri data from standard
80- olumn pun hed ards; they a ept numeri data from
pun hed identifi ation badges and manual entry units. The
DEU’s a ept ten positions of numeri data from pun hed
| ards or pun hed badges; they also a ept information from
manual entry units. The AS and DEU information is trans
mitted by area stations to a transmission ontrol unit
(system ontroller). The transmission ontrol unit (TCU)
ommuni ates with an IBM System/360 via a lo al (multi
plexer hannel) or a remote (binary syn hronous trans
mission line) atta hment.
Either an IBM 2715 Transmission Control Unit or an
IBM 1800 Data A quisition and Control System with an
1800/2790 Adapter may be used as the system ontroller
for the 2790 system. For further information about the
IBM 1800 performing as the system ontroller, see Systems
Referen e Library manual, IBM 1800 Data Acquisition and
Contro System Functiona Characteristics, GA26-5918-7,
with TNL N26-0241, or a later version.
The IBM 2790 system onfiguration onsists of a entral
pro essor (IBM System/360), a transmission ontrol unit
(IBM 2715), area stations (IBM 2791 or IBM 2793), data
entry units (IBM 2795 or IBM 2796), and other I/O devi es.
The 2790 system onfiguration onsists of as many as 100
AS’s onne ted in a loop onfiguration, starting and ending
at the TCU. Adja ent units of the 2790 Data Communi
ation System are onne ted by a twisted-pair able (ex ept
the IBM 1035 Badge Reader and IBM 1053 Printer whi h
atta h to the area station by multiwire able). 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 oaxial able (Figure 2). DEU’s an be atta hed
to an AS. Conne tion between a DEU and an AS is estab-
Data Entry Units
Figure 1. Typical IBM 2790 Data Communication System
Introduction 5

Up to 100 Area Stations
Up to 1024 Data Entry Units
Up to 32 Data Entry Units per 2791 Model 1 or 2793 Area Station
Up to three 1035 Badge Readers per 2791 Model 1 Area Station
One 1053 Printer per 2791 Model 1 or 2793 Area Station
| Up to 35 Area Stations per segment
Up to 1000 wire feet of two-wire communications line between Data Entry Units and Area Stations (No 22 AWG Twisted Pair) or 4500 feet using RG1 30/21 Coaxial Cable
Up to 1000 wire feet between Area Stations or between 2715 and Area Stations (No 22AWG Twisted Pair) or 4500 feet using RG130/21 Coaxial Cable
| See the Installation Physical Planning Manual GA27-3017-1 or later version for distances with other wire sizes
• Figure 2. IBM 2790 Configuration
I
lished by a two-wire ommuni ations line whi h may also
be up to 4500 feet. No lo ally supplied power is required
at the 2795 and 2796 Data Entry Units.
The IBM 2790 Data Communi ation System supplies
the latest information to the data pro essing enter, thus
diminishing the time gap between the organization of data
and its availability for use.
Some of the appli ations of the 2790 system are:
Produ t Control
Material Control
Labor Control
Tool Control
Quality Control
Attendan e Re ording
The advantages of the 2790 system over previous data
olle tion systems are:
6
1. The 2790 system is apable of high-speed data
transmission (approximately 900 hara ters per
se ond partitioned among the a tive terminals
on the loop).
2. Guidan e lights on the 2791 Area Station inform
the operator of the next operation the system
ontroller expe ts.
3. The 2790 system has the ability to ontrol a large
number of devi es (up to 100 area stations, 1024 data
entry units, 100 IBM 1053 Printers, and 300 IBM 1035
Badge Readers).
4. The DEU’s are inexpensive, an be atta hed to the
AS by a two-wire ommuni ations line, and require
no lo ally supplied power.
TYPICA L APPLICATIONS
The following dis ussion illustrates a 2790 system perform
ing typi al appli ations in a manufa turing plant.

Attendance Recording
The IBM 2790 system may be onfigured in two ways for
attendan e re ording. Where high-rate attendan e re ording
is required, the IBM 2791 with either the resident badge
reader or remote IBM 1035 may be used to provide a re ord
of the employee’s man number. (The system automati ally
inserts the time and lo ation into ea h transa tion.)
In other appli ations (with lower required entry rates),
the IBM 2795 or 2796 may be used.
Material Control
When raw material, pur hased parts, or assemblies are with
drawn from sto k, the IBM 2790 system provides an up-to-
date re ord of material on hand. A 2795 DEU or 2796 DEU
is installed in ea h sto k room. A prepun hed ten- olumn
ard or badge ontaining a file-re ord identifier for su h
information as material, part number, quantity, and sto k
room lo ation is inserted in the DEU. Ten olumns of
numeri data together with variable fields are transmitted
to the data pro essing system, updating the parts inventory.
Production Control
The ontrol of produ tion requires management to know
the status of work flow through the various steps of the
manufa turing pro ess. Data entry units installed at appro
priate ma hine lo ations and he kpoints an be used to
re ord dynami ally the time spent on ea h operation, work
pile-ups, quantity of parts flow, et . This data re orded on
the system is available to management for he king the
progress of an individual order through the shop, and work
ompleted for ea h step of the operation. It an also be
used to determine the need for additional apa ity at spe ifi
steps of the operation, or the need to shift work load to new
areas. Information on the status of shop loads an be used
in determining standard lead times for produ tion s heduling.
Introduction 7

Data Entry Units
The 2795 DEU and the 2796 DEU (designed for ruggedness
and simpli ity) are operator-oriented devi es for use in a
fa tory. The 2795 DEU is a small me hani al unit
(approximately 7 in hes by 10 in hes) ontaining a badge-
ard reader, two 10-position rotary swit hes, a phone-ja k,
an error indi ator/reset button, an entry flag, and an entry
request lever, all pa kaged in a single ompa t unit for
ben h or wall mounting (Figure 3). Wall mounting requires
| a ustomer-furnished shelf or bra ket.
The 2796 DEU ontains all the fun tions of the 2795
DEU plus two additional 10-position rotary swit hes, four
ro ker-thumbwheel swit hes, and a monitor key(Figure 4).
The DEU is onne ted to the AS by a ustomer-furnished
two-wire ommuni ations line, and ontrolled by the AS.
2795 DATA EN TRY UNIT
The 2795 DEU in ludes the following features.
Badge-Card Reader
A badge- ard reader lo ated on the top of the DEU reads
ten digits of numeri information pun hed as shown in
Figure 5.
The badge- ard reader an read ten olumns of numeri
data from either end of a pun hed ard or ten olumns of
numeri data from a 357/1030 style badge. Cards to be
read on a DEU should not have a 9-edge orner ut; a
9-edge orner ut may ause reading problems.
The DEU’s read 0 through 9 pun hes and blanks. If no
0 through 9 pun h is in a data olumn, the DEU reads that
olumn as a blank. If a data olumn is double pun hed, the
DEU reads the pun h losest to the 9-edge and ignores the
other pun hes in the olumn.
This numeri information is provided by the following
ombinations of pun hes in a standard 80- olumn ard, or
in the equivalent positions (Figure 5) of an identifi ation
badge.
Entry Flag Carcf/Badge Slot
Error Indicator/Reset Button
Phone Jack Entry
Request
Lever
Figure 3. IBM 2795 Data Entry Unit
Data Entry Units 9

Entry Flag Card or Badge Slot Error Indicator/
Reset Button
Monitor Key and
Phone Jack on
Left Side
Rotary Switches Rotary Switches
Figure 4. IBM 2796 Data Entry Unit
80 Column Card
Numeric Data
Col 71-80-Card fed 80
olumn end first, fa e
towards operator
Col 10-1-Card fed ol
umn 1 end first, fa e of
ard away from
operator
Identification Badge
Numeric Data
IBM 013 Badge Pun h
olumns 13 through 22
Registration Punches
Col 66—“9” and “11”
pun hes
Col 15—“9” and “11”
pun hes
Registration Punches
IBM 013 Badge Pun h
olumn 8—“9” and “11”
pun hes
2795 Data Entry
A 2795 data entry as assembled in the 2715 TCU onsists
of 12 digits of data plus transa tion-header information
(see Figure 6):
Digit 1—Type of DEU.
Digit 2—Setting of right-hand rotary swit h.
Note: Su h information as devi e address, area station
address, and left-hand rotary swit h setting are also
transmitted to the system ontroller. The system
ontroller onstru ts a transa tion header from this
information and prefixes it to the transa tion ontaining
the data entry.
Selection Switch
Note: Detailed information about the badges used for
the 2790 system is given in the Systems Referen e
Library Manual, 357/1030/2790 Badge Specifications,
GA21-9028.
A 10-position rotary swit h is lo ated on ea h side of the
DEU frame. These swit hes are apable of transmitting
numeri digits 0 through 9 to indi ate su h things as
status, names, or numbers. The transmitted digits are
10