Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 20 - CalAmp Proprietary & Confidential

4.5.2 Keeping the Expansion Port powered during sleep

The expansion port is the 16 pin connection on the back of the LMU where peripheral

devices are plugged in. This port can actually remain powered while the LMU is sleeping.

This would be done to allow any of the following:

• Keep Inputs and Outputs on the ioPOD in the High/Low or Set/Cleared states

• Allow the LMU to wake up on inputs connected to the ioPOD

• Allow the LMU to wake up based on host port activity

The power of the expansion port is controlled by bit 6 of S-Register 140. If this bit is set,

then the expansion port remains powered while the LMU is sleeping. If this bit is cleared,

the expansion port will be powered down when the LMU goes to sleep.

To keep the port powered on, you would use:

AT$APP PARAM 1024,20,64,64

To power it off during sleep you would use:

AT$APP PARAM 1024,20,64,0

Keep in mind that leaving the expansion port powered will increase the current draw of the

LMU during sleep.

4.5.3 Keeping the Modem On during sleep

In some installations it may be desirable to be able to wake the LMU from sleep remotely.

The LMU can support this by being configured to leave its radio on while sleeping.

To enable this feature you need to set Bit 2 of S-Register 171.

Enable Radio-On Sleep Mode

AT$APP PARAM 1024,51,2,2

Disable Radio-On Sleep Mode

AT$APP PARAM 1024,51,2,0

The LMU will wake when it receives any SMS message.

Be advised that the LMU will draw noticeably more power using this sleep mode.