How to find out the SIM card number in the GPS tracker without taking it out to see?

How to do if the uers forgot the SIM card number in the GPS tracker or lost the SIM card record?

Especially the GPS tracker has installed on the vehicle and is far away.

There is a way below:

Condition: the GPS tracker must be online in our tracking platform when send the TCP/IP command.

Because the users forgot the SIM card, so can't send the SMS command. But the users can send the GPRS (TCP/IP) command from the tracking platform to the GPS tracker device.

GPRS command format:

B30,0,X

X is your own phone number.

For example:

B30,0,13412345678

After the GPS tracker received this command, it will call the X number. Then you will know the SIM card number in the GPS tracker according to the displayed incoming call number on your phone.