Modem as a service?

We are looking to automate testing of OOB modem connections when our NMS detects a site connection failure. Rather than have a live body call a modem number (or even a fax) to see if it answers (to determine if there is a potential site power issue), we'd like to be able to utilize some "Modem as a service" to automate this. I've exhausted my Google skills trying to see if anything like this exists. Anyone have any experience? Thank you, James Laszko Mythos Technology Inc jamesl@mythostech.com<mailto:jamesl@mythostech.com>