How does SMS with Asterisk work

I’m trying to figure out what I need to know to be able to send SMS with Asterisk. Do I need some sort of provider ot ir’s totally free ? Does Asterisk contain every thing to be able to send/receive SMS ?

I’m in canada so I can’t use any sort of GSM gateway.


Read first:

I made it like this:

exten => _2,2,System(/usr/src/asterisk/utils/smsq YYYYYYYY Testuser called in and left a voicemail for you! --motx-channel=ZAP/2/XXXXXXXXXX)

where XXXXXXXXXX stands for your gsm telco centre providing sms service for fix line and YYYYYYYY for the gsm nummer you’re going to send the sms.

hope that helps