What are AT Commands?
According to Codeproject.com, AT Commands are instructions used to control a modem. AT is the abbreviation of ATtention. Every command line starts with "AT" or "at".
AT command sequence for proper network connection
When configuring a new device, you need to configure the AT command sequence to fit with your use-case.
To avoid incorrect device configuration, SAP Digital Interconnect recommend that you implement the following AT command sequence to connect and disconnect properly from/to the mobile network:
Measure the signal quality
Enable network registration
Return the current state of the network registration: Attach/Detach
Attach the terminal to GPRS service
Return the current state of GPRS service: Attach/Detach
Define PDP Context
Measure signal quality
Activate a PDP context
Return the current state of the PDP context
Deactivate a PDP context
Note: Please check the manual from your module vendor for the exact AT command to use.