SMS mode in repeated send/receive messages mechanism


I would like to understand if the ‘AT+CMGF=0/1’ (mode status of the SMS) can be somehow changed automatically?

I’m asking because I have a mechanism to poll the SMS storage and check for new messages every X seconds.

My steps to read an SMS every X seconds :

  1. Set mode: ‘AT+CMGF = 1’
  2. Read a message : 'AT+CMGR = index_num ’
  3. Do something with the SMS.

What I would like to know is if the MODE of SMS can be set only once and not on every SMS read?
Can I be sure that it won’t change somehow automatically?


Yes, it persists until changed again, or the modem gets a hard reset or power-cycle.