Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 48 - CalAmp Proprietary & Confidential

Up to two Contexts can be defined. The first Context is stored in index 0 of parameter 2306,

the second is stored in index 1.

Which Context the LMU will initially use is controlled by the GPRS Context – Current

Index Parameter (2307). If the value of this Parameter is 0, the LMU will start with the first

Context, if the value is 1 it will start with the second. For instance, to use the second Context

you would use:

AT$APP PARAM 2307,0,1

The automatic switching of the active Context is controlled by S-Register 129. This register

defines how many connection attempts the LMU is allowed to make before it automatically

switch to the next Context. A failure is indicated by a Comm Disconnect PEG event and/or

debug message on the host port.

For example, to set a failure count of 5 you would use:

ATS129=5

In this case, if the LMU was using the first Context it would allow 5 connection failures

before switching to the second. If it fails 5 times on the second, it will switch back to the

first.

The automatic switching feature is disabled if S129 is set to 0. By default, S129 is set to 3.

7.3

The LMU can automatically reset its internal wireless modem based on a variety of

conditions. Please keep in mind that these features only apply to the LMU-4100.

Automatically resetting the wireless modem

7.3.1 Send fail restart

In some cases it may be desirable to automatically reset the wireless modem based on its

inability to send in PEG event reports. This is controlled by the Send Fail Restart Count,

which is stored in S-Register 149. If the LMU attempts to send in an event report more than

the number of times indicated in S-149, the LMU will automatically reset the wireless

modem. A send failure occurs at the following stages:

• when the inbound retry schedule (Ignition on or off) expires

• when a log send retry interval expires

For instance, to reset the wireless modem after 8 send failures you would use:

ATS149=8

To disable this feature, set S149 to 0.