Programming Guide

CHUMP Reference Guide
8
CHUMP Protocol Overview
Unlike most HDLC protocols, CHUMP uses ASCII characters
for the Flag, Address, Control, and FCS fields. Punctuation
characters substitute for the more common (but unprintable) STX
and ETX characters, providing a human readable message frame
or packet.
Although not fully packetized, CHUMP can be described as
operating between Layer 2 (Data Link Layer) and Layer 3
(Network Layer).
CHUMP Frame
As shown in Figure 4, each CHUMP frame consist of a Message
Head, Command Block, and a Message Tail.
Figure 4 - CHUMP Message Format