Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 73 - CalAmp Proprietary & Confidential

appropriate acknowledgement) or it reaches the bottom of its Inbound list. Upon reaching

the bottom, the LMU will wrap back to the top of the list and try again. The selection of the

next IP address will occur when the Inbound Retry Schedule expires or when the Log Retry

Schedule expires.

The LMU provides several modes to handle which inbound address is used.

10.2.4.1 Dynamic Inbound Address

Dynamic Inbound Address mode allows the LMU to automatically switch its Inbound

address based on the last IP address to contact the LMU. If the LMU is unable to deliver a

report to the new IP address or has never been contacted, it will use its normal Inbound IP

Address list.

To enable this mode, bit 2 of Parameter 1280 must be cleared.

AT$APP PARAM 1280,0,4,0

It should be noted that the LMU will not dynamically redirect the port number. The LMU

will use the first port number in its Inbound Port list (i.e. Parameter 769, Index 0). To

include the port number in the Dynamic redirection you must set bit 5 of Parameter 1280

AT$APP PARAM 1280,0,32,32

10.2.4.2 Static Inbound Address

While in Static Inbound mode, the LMU will not switch its Inbound IP address based on the

last message received. That is, the LMU’s inbound reporting is locked to the contents of the

Inbound IP Address List (i.e. Parameter 768). This is the default mode of the LMU.

Static Inbound is enabled by setting bit 2 of Parameter 1280.

AT$APP PARAM 1280,0,4,4

Please note that the Static Inbound setting will over-ride both the Dynamic and Random

Inbound modes.

10.2.4.3 Random Inbound Address

Random Inbound dictates how the first IP Address the LMU uses is chosen. From Power

Up, the LMU will randomly select which Inbound IP Address it will use (0-3). If the LMU is

unable to send data to that IP Address, it will progress through the rest of the inbound IP

addresses as if it were in Standard Mode. That is, it will select the next in the list and make

another attempt. If it reaches the bottom of the list, it will return to the top until it gets a

data delivery acknowledgement.