In addition to the suggestions provided by Matt, you could attach an external modem to one of your serial ports. When the alarm case is triggered, you could activate the modem (using VISA), dial out to the pager number and send a numeric message. You would do this primarily using the old AT style command strings. I have done this before using an FP-20XX module.
Regards,
Aaron
LabVIEW Champion, CLA, CPI