Original Amstrad RS232 interface

RS232C

SERIAL INTERFACE

USER INSTRUCTION BOOK AMSTRAD RS232C SERIAL INTERFACE WITH ROM SOFTWARE AND POWER SUPPLY AMSOFT A division of CONSUMER ELECTRONICS PLC. © Copyright 1985 AMSOFT, AMSTRAD Consumer Electronics plc. Neither the whole nor any part of the information contained herein, nor the product described in this manual, may be adapted or reproduced in any material form except with the prior written approval of AMSTRAD Consumer Electronics plc. (‘AMSTRAD‘). The product described in this manual, and products for use with it are subject to continuous development and improvement. All information of a technical nature and particulars of the product and its use (including the information and particulars in this manual) are given by AMSTRAD in good faith. However, it is acknowledged that there may be errors or omissions in this manual. and a list of details of any amendments or revisions can be obtained by sending a stamped, self addressed envelope to AMSOFT Technical Enquiries.

AMSOFT welcome comments and suggestions relating to the product or to this manual.

All correspondence should be addressed to:

AMSOFT Brentwood House 169 Kings Road Brentwood Essex CM14 4EF

All maintenance and service on the product must be carried out by AMSOFT authorized dealers. Neither AMSOFT nor AMSTRAD can accept any liability whatsoever for any loss or damage caused by service or maintenance by unauthorized personnel. This guide is intended only to assist the reader in the use of the product, and therefore AMSOFT and AMSTRAD shall not be liable for any loss or damage whatsoever arising from the use of any information or particulars in, or any error or omission in, this manual or any incorrect use of the product.

CP/M is a trademark of Digital Research Inc. Z80 is a trademark of Zilog Inc. AMSDOS, CPC464, CPC664, CPC6128, DDI-1, and FD-1 are trademarks of AMSTRAD. First Published 1985

Written by Roland Perry Illustrated by Alexander Martin

Electronics and SIO drivers by MEJ Electronics

Programming by AMSOFT:

Printer re-direction, PRESTEL, and TERMINAL by David Radisic File transfer by Vik Olliver

Concepts by Roland Perry Consolidation and ROM housekeeping by Cliff Lawson Edited by Ivor Spital

Published by AMSTRAD Typeset by KAMSET typesetting graphics (Brentwood)

AMSTRAD is a registered trademark of AMSTRAD Consumer Electronics plc. Unauthorized use of the trademarks or word AMSTRAD is strictly forbidden. When you have fitted the AMSTRAD RS232C to your computer, you have the means to communicate with printers, modems, and other computers. Implementing such a link is often regarded as a very mysterious and complicated business, if only because of the serial interface‘s inherent flexibility and versatility. To help you use your AMSTRAD RS232C serial interface, we have provided instructions in the form of ‘magic spells‘. Simply select those spells which are relevant to your application by identifying the accompanying sketches.

A full technical explanation is available in a series of appendices. The examples in these ‘spells‘ are not intended to be an exhaustive survey of all the possible uses of the RS232C. They do represent, however, the majority of applications encountered.

The AMSTRAD RS232C serial interface, and these instructions, are suitable for use with the AMSTRAD CPC464, CPC664 and CPC6128 computers. The AMSTRAD RS232C works equally well with any of these computers. Some of the applications referred to work best with a disc drive, although cassette tape storage is usable as an alternative. Some disc drive applications will require CP/M 2.2 (supplied with both the CPC664, and with the DDI-1 add-on disc system for the CPC464), or CP/M Plus (supplied with the CPC6 128).

When operating in BASIC, the additional commands provided for the RS232C are programmed in a ROM supplied inside the RS232C and are accessed by keywords starting with a bar | symbol. The bar symbol is obtained by pressing

[SHIFT]@

The CP/M commands referred to are supplied on your standard CP/M system disc. The use of a serial interface allows you to connect equipment together using very simple wires up to 50 feet long. It is possible, using a modern, to convert the signals in these wires into a form in which they can be sent almost any distance to another modern, over standard telephone lines. Most equipment manufacturers have agreed the connection details to a standard called ‘RS232C‘. It is also possible to connect devices which conform to the alternative ‘RS423‘ standard.