Difference between sleep mode

GPS Sleep mode:
The device is able to go into GPS sleep mode if such mode is enabled.
Sleep mode timeout starts counting when the device is in STOP mode. After timeout is reached and all conditions for GPS sleep mode are met, the device goes into sleep mode.
When in GPS sleep mode, the device turns the GPS module off and continues making new periodic records. As a result power usage decreases, in turn saving vehicle battery.

Deep sleep mode:
While in deep sleep mode, the device sets the GNSS receiver to sleep mode and turns off GSM/GPRS module (hence it is not possible to wake up the device via SMS). Despite records with the last known coordinate being saved and sent to the AVL server (GSM/GPRS module is turned on to send data and then it is turned off), power usage is decreased to save the vehicle's battery.

Online Deep sleep mode:
In this mode, the device works as in deep sleep mode, but without deregistering from the GSM network. GSM part stays powered so this increases power consumption. In this mode, the device should send/receive SMS and make/accept calls. It does not close the GPRS context if one was previously opened.
Conditions to enter online deep sleep mode are the same as entering deep sleep mode.

Ultra Deep sleep mode:
Conditions to enter ultra deep sleep mode, where GPS and GSM modem are turned off and device functions are suspended for maximum battery saving, are the same as entering deep sleep mode.