Here are the Default I/O Mappings for Digital Matter's Oyster 3 tracker. You can change some of these mappings on OEM server - we do not recommend changing these unless you know what you are doing. 
These mapping can be very handy to identify and debug issues. 

For example, if the device is connecting to the server/platform intermittently, this maybe an issue with coverage which can be confirmed by analyzing/plotting Analogue 4 (Cellular Signal Strength).

For information on the battery flags, see Battery Level Monitoring [Oyster3].

All DM devices have 'status flags'. The status flags are sent in Field 2 to 3rd party servers. However in Telematics Guru, they are remapped to the following Digital Inputs.