GPS Positioning tracker and SIM card number setting method

Search for information on the Internet and find that the GSM module has no command to obtain the SIM card number.

What should I do if my device needs to identify its identity using SIM card numbers and other parameters?

If there is only one, I can write the SIM card numberProgramBut if I change the SIM card, what should I do if I need to update the card number parameter? What should I do if I create n in batch ??

Note: There is no display screen or keyboard for the device volume limit, which means manual input by the user is not feasible.

After a long time, I suddenly saw a product on the market one day. I set the parameters by sending a text message to the target number. Well, you can copy it.

I will write down my current ideas for reference:

After the program is installed on the device, the default card number and other parameters are blank. At this time, the device is in the waiting status even if it is powered on (only receive text messages and nothing else ).

After the SIM card is installed, send the actual SIM card number and other parameters to the device by text message.

After receiving the SIM card number setting, the device immediately enters the working status. Use the SIM card number to connect to the center to identify the center.

The above idea has a hidden danger: A general mobile phone can achieve the goal of modifying device parameters. If someone is malicious, the system may be confused.

There are several solutions:

1. The device can only be initialized once (this type of text message is no longer accepted after it enters the working state). The service center must modify the setting again through the network. This basically eliminates the risk of malicious modification, but in case of setup errors, you can only return to the factory to refresh the program.

2. encrypt the initialized text message content (add verification data). This only reduces the risk of malicious modification and cannot be eliminated.