Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 76 - CalAmp Proprietary & Confidential

Message Interval in Parameter 2313. Keep in mind use of the Null Message may have

noticeable impacts on you data usage if the interval is set to an extremely low value. The

Null Message Interval can range from 1 to 65535s. A value of 0 disables the Null Message.

For example, to set a 2 minute Null Message Interval you would use:

AT$APP PARAM 2313,0,120

If another LM Direct message is sent before the Null Message Interval expires, the Interval

is reset. This is meant to keep data usage to a little as possible.

The Null Message is sent using the Unacknowledged service and thus is never logged.

10.5

The LMU’s Local Port is used to listen for Outbound (i.e. Server to LMU) LM Direct

messages. This UDP port number can be changed by altering Index 0 or Parameter 774. For

example to set the LMU to use a port number of 9000

Changing the Local Port

you would use:

AT$APP PARAM 774,0,9000

This field is defaulted to 20510 unless otherwise defined.

It is generally a bad idea to use well known UDP Port numbers for either the Inbound or Local Port

settings.