security: gsm + asterisk

[domotiqa.com]

For security reason, I'd like to have lmce to be able to send sms... if someone kill the phone line

I'd like feedback about these options I have under lmce and specialy asterisk:
- FXO + cellsocket
- bluetooth phone connection (Addons (chan_mobile))
- voip gsm gateway
and for example common hardware that is "pnp"/cheap

thanks