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THE UNIVERSITY OF MICHIGAN Memorandum 4 PDP-8/103A DATAPHONE INTERFACE

IP.com Disclosure Number: IPCOM000128419D
Original Publication Date: 1966-Nov-01
Included in the Prior Art Database: 2005-Sep-15
Document File: 3 page(s) / 16K

Publishing Venue

Software Patent Institute

Related People

Lundstrom, Stephen F.: AUTHOR [+3]

Abstract

The Concomp Project's DEC 338 Display system is now interfaced to two Bell System 103A Dataphones. This memorandum describes the use of the system as well as the interface construction.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 53% of the total text.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

THE UNIVERSITY OF MICHIGAN Memorandum 4

PDP-8/103A DATAPHONE INTERFACE

Stephen F. Lundstrom CONCOMP: Research in Conversational Use of Computers ORA Project 07449
F. H. Westervelt, Director

supported by: DEPARTMENT OF DEFENSE ADVANCED RESEARCH PROJECTS AGENCY WASHINGTON, D. C.

CONTRACT NO. DA-49-083 OSA-3050 ARPA ORDER NO. 716

administered through: OFFICE OF RESEARCH ADMINISTRATION ANN ARBOR November 1966

ABSTRACT

The Concomp Project's DEC 338 Display system is now interfaced to two Bell System 103A Dataphones. This memorandum describes the use of the system as well as the interface construction.

[ Chapter ] I. GENERAL DISCUSSION

The interface to the 103A Dataphones required only minimum hardware additions. It involved the use of the teletype control built into the PDP-8. Figure 1 shows the standard system configuration.

(Image Omitted: Figure containing following caption omitted: Figure 1. Standard PDP-8 TTY I/O Configuration.)

(Image Omitted: Figure containing following caption omitted: Figure 2, below shows the additions to the above basic system.)

(Image Omitted: Figure 2. Modified PDP-8 TTY I/O Configuration.)

Notice that the console typewriter is now essentially an independent console since it is connected to its own dataphone. In particular, it may be connected to the PDP-8 to operate as a

University of Michigan Page 1 Nov 01, 1966

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THE UNIVERSITY OF MICHIGAN Memorandum 4 PDP-8/103A DATAPHONE INTERFACE

normal online teletype with one exception: the tape reader on the ASR 33 will advance as long as there is tape in the reader (similar to handling tape in the reader during interrupt control of the normal online configuration.

[ Chapter ] II. PROGRAMMING CONSIDERATIONS

The new system is programmed using the standard PDP-8 IOT Instructions for teletype I/O (see the PDP-8 User's Handbook). The programmer should note the comment above concerning the independence of tape advance from the TTY reader flag. Also, the programmer should note that many standard Bell System teletypes automatically generate a parity bit which appears as the high order bit of the 8-bit character code. In such cases, there will be no guarantee that the high order bit is set during input from the keyboard as is the case with the ASR 33 supplied with the PDP-8.

[ Chapter ] III. SYSTEMS CONSIDERATIONS

The new PDP-8 I/O configuration allows a wider degree of flexibility in the integration of the 338 Display into The Uni...