The DGH D3000 and D4000 series products use a simple command and response protocol. A module must be interrogated by a host computer to obtain data. A module will never initiate a command sequence in order to prevent communications collisions.

A command is initiated with a command prompt, may be a dollar sign ($) or pound sign (#). Following the prompt a single address character must be transmitted. Each module on a communications bus must be setup with a unique address. The address is followed by a two character command. Every command is terminated with a carriage return.

The module response begins with a response prompt, which is an asterisk (*) followed by the necessary data. Every response is terminated with a carriage return. Linefeeds after the carriage return are user selectable. See the table below for typical commands and their respective response messages.