scope:

INTRODUCTION

This specification is divided into 3 major Section. The First, Section A, is a statement of the principles which have governed the design of the ASWE Serial Highway. It is included as background information to assist the reader of the other 2 Sections in understanding some of the reasoning behind the design decisions.

Section B is a specification of the highway protocols at the electrical, the format and the logical levels. It contains all the information required to design and construct a highway terminal unit.

Section C specifies a recommended interface between a highway terminal unit and a computer in the subsystem it serves. This is mainly specified at the software level, reference to other documents being required for details of the electrical and logical levels. It is hoped that the software level of specification will be largely invariant from computer to computer.