Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 34 - CalAmp Proprietary & Confidential

back-end system. Please note that the LMU will still obey its maximum buffer size (804

bytes) even if the Termination Length is undefined.

The Termination Timeout is controlled by S-Register 138 and ranges from 1 to 255ms.

For instance, to set the timeout for 120ms you would use:

ATS138=120

Like the Termination Length, setting S-register 138 to 0 will disable the Termination

Timeout feature.

5.1.4.7 MDT Mode – User Message ID

The User Message ID field serves two purposes for User Messages. First, the LMU will tag

any inbound (LMU to server) User Messages with the defined Message ID. This will appear

in the User Message ID field of the LM Direct packet. The second function is to act as a

filter on any outbound (server to LMU) User Messages. If the outbound User Message does

not have the same ID as the LMU, then the contents of the User Message will not be sent to

the serial device. The Message Received PEG Trigger however, will work regardless of

matching User Message IDs.

The Message ID can range from 0 to 255 and is defined in S-Register 136. For instance, to

define a User Message ID of 4, you would use:

ATS136=4

This feature is always enabled, so it is very important to co-ordinate this setting with

whoever is responsible for your LM-Direct implementation.

5.1.4.8 MDT Mode – Message Disposition

The message disposition defines how the LMU’s log will handle the User Messages. There

are six options:

• Attempt to send the User Message immediately. The message will be logged if the

send fails or if the log is already active.

• Immediately log the User Message

• Immediately send the User Message using the Unacknowledged service and place a

copy in the LMU’s log. (i.e. Priority Message)

• Send the User Message using the Unacknowledged service (i.e. message is never

logged)

• Route the User Message (contents only) to the SMS Destination Address

• Route the User Message (contents only) to the last phone number of an incoming

SMS message

With the last two options the contents of any incoming SMS messages will be routed to the

serial device.