Introduction

Scope of Document

This document specifies an Arbitrary Text Display device which may be installed on GM vehicles. The display device assumes no prior knowledge of what is to be displayed. It will provide a basic display message transfer capability using the GM Class 2 data link and a subset of the Arbitrary Text Display Class 2 Protocol to achieve the transfer of data for display.

The Arbitrary Text Display device in this specification is considered to be a subassembly of a driver display cluster or other vehicle display center. As such, it is assumed that any packaging, mounting, power supplies, EMC requirements, etc., will be part of the display center specification and therefore these will not be included in this specification. In addition, it is the responsibility of the cluster or display center to decide which priority the arbitrary text display data will have in the presence of competing display messages from other souces.

Not all features described in this specification need be implemented in any particular display device. Those features designated in section 4 – Available Display Features and Attributes, as options may or may not be included. All other features not designeated as options shall be implemented on all Arbitrary Text Display Devices. However, when features are implemented they shall operate according to this specification. While it isintended that this specification shall form the basis for generating a purchasing specification for a device which utilizes a standard GM Arbitrary Text Display, it is not a purchasing specification. It is to describe all possible features and a standard method of utilizing the features using the Class 2 data link messages specified herein.