SIM800 disable receiving text/calls [AT CMD]

Hi,

Currently I'm working on a system that sends data by GPRS.
The system crashes if someone texts/dials the number of the SIM-card inserted.

I looked in the AT-command manual and couldn't find a way to block incoming calls/sms.

Is there a way?

EDIT: I found AT+GSMBUSY = 1 which blocks all incoming calls.
I hope it doesnt wake the SIM800 from sleepmode.

Thank you :o