Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 69 - CalAmp Proprietary & Confidential

The primary interface to the LMU once it is in the field is LM Direct. LM Direct is a

UDP/IP based protocol that allows you to:

CalAmp LMU Interface – LM Direct

• Receive location data from the LMU based on the PEG Script

• Request location and status data from the LMU based on Unit Request messages

• Send and Receive User Messages to/from host serial devices

• Make configuration changes to various LMU parameters.

The LM Direct protocol is discussed in detail in the LM Direct Reference Guide. The

discussion that follows describes the LMU’s various configuration settings that support the

LM Direct interface.

10.1

In order to use the LM Direct Protocol it must be enabled. This is done using S-Register

140. If bit 4 is set, then the LM Direct protocol is enabled. If it is cleared, then the LMX

Using the LM Direct Protocol

protocol is enabled. To enable LM Direct, you would use:

AT$APP PARAM 1024,20,16,16

The LM Direct protocol is, of course, enabled out of the factory, so this is usually an

unnecessary step.

10.2

The destination for all LM Direct data created by the LMU is known as the Inbound

settings, which are made up of three Parameters:

Inbound Settings

• Inbound IP Address (Parameter 768)

The Inbound IP address is the IPv4 address of your backend system

• Inbound Port (Parameter 769)

The Inbound Port is the UDP port number your server is listening on for LM Direct

packets. This is generally set to 20500.

• Inbound URL (Parameter 2319)

The Inbound URL allows the LMU to look-up the Inbound IP Address using DNS.

If the DNS look-up is successful, then the LMU will over-write the Inbound IP

address with the new value. If the DNS look-up fails, then the LMU will use the

current Inbound IP Address. This feature was designed to allow users to easily

change IP Addresses of the backend system without having to update the

configuration of every LMU in a given fleet

Users may also enter an IP Address directly in this field. (eg 192.168.0.1)

LMX is an older protocol in the LMU and is only present for reasons of backwards compatibility. It is no

longer officially supported by CalAmp.