Table of contents

  1. Overview
  2. Basic Message Packet Structure
  3. Wireshark Filter & Sample Hex dump
  4. Reference

Overview

Radio to ELM or CM interface between a radio and an ELM or a CM primarily supports the passing of data messages to and from the radio. It also supports service messages to control the flow of information across the interface. This interface is defined by the Host/Radio eXchange (HRX) Protocol. HRX is an application level protocol which is transported over Class D and TCP/IP

Basic Message Packet Structure

HRX service message

HRX data message from ELM or CM

HRX data message from Radio to ELM or CM

Wireshark Filter & Sample Hex dump

HRX message type: data message (‘D’)

(tcp.srcport == 9000 || tcp.dstport == 9000) && tcp.payload[0:2] == 02:02 && tcp.payload[12:1] == 0x44

Reference

US10469586
ITCRSystemSpecification