Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 49 - CalAmp Proprietary & Confidential

7.3.2 Log activity restart

This feature is similar to the Send Fail Restart, only it is time based instead of packet delivery

based. In this case, the LMU will reset the wireless modem if the LMU’s log space has been

active for a specific period of time. This period is defined by S-Register 157 and is stored in

minutes. This timer starts when the LMU’s log goes active and reset when it empties. As an

example, if we want to reset the LMU’s wireless modem if the log has been active for 30

minutes we would use:

ATS157=30

It is highly advisable to set this value to something greater than the length of time it takes the

LMU to empty a full log. This can be around 20 minutes depending on the wireless

technology employed.

7.3.3 Connection monitoring

The LMU’s Connection Monitor is a third means to automatically reset the LMU’s wireless

modem. In this case, the LMU issues a heartbeat message to the wireless modem in the form

of an LCP Echo. If the modem does not respond to three consecutive LCP Echo requests,

the LMU will reset the modem. LCP Echoes are sent in two instances; either on a periodic

basis or after each LM Direct packet is sent. Please keep in mind that LCP Echoes should

only be used with modems that locally maintain a PPP session with the LMU. That is, any

device that uses CDMA 1xRTT or a circuit switched session for its data connection MUST

NOT use the Connection Monitor

. Doing so may violate the network terms of service

and/or add significant cost to your wireless data charges.

There are three settings that control the Connection Monitor, one which controls how often

the LCP Echo is sent, one that controls the LCP Echo sent after LM Direct packets and one

that is a master enable/disable control. The LCP Echo interval is controlled by S-Register

152. The value of this Register is the length of time, in seconds between LCP Echoes. For

instance, to use a 20 second interval, the AT Command would be:

ATS152=20

Setting value S-152 to 0 disables the periodic LCP Echo.

The sending of LCP Echoes after LM Direct packets is controlled by bit 2 of S-154. To

enable the sending of LCP Echoes, you would set this bit. That is:

AT$APP PARAM 1024,34,4,4

To disable the sending of LCP Echoes after LM Direct packets, you would clear bit 2 using:

AT$APP PARAM 1024,34,4,0

The Connection Monitor is always disabled for both the internal and external CDMA modem drivers

regardless of LMU settings.