A common method is to send notifications to an e-mail system (MS Exchange) and then use an SMS plugin to MS Exchange to then send out SMS text messages.
You would need a notification method that uses email but which send notifications in a fixed format that MS Exchange knows to send out as SMS messages.
In the olden days (which means anything over 5 years ago ) it was possible to attach a Modem to your SD primary server and call software that came with the modem to send SMS messages via the Modem. I can't see that anyone would do it that way any more.
Carey