said by tlhIngan :

Shaw isn't VoIP though.

It's technically VoIP, but the voice data doesn't go over the public internet, and thus isn't affected by outages to your broadband internet connection. Your internet connection can go out, but Shaw Digital Phone can't.

Shaw Digital Phone is a replacement for your phone service - you cannot take the terminal and move it to another house because it's provisioned to a specific node. That's why 911 works by default.

Shaw Digital Phone is a completely reliable replacement for Telus or the phone company, and is designed to provide carrier grade service. It's partly why during extended power outages Shaw has to roll trucks to keep changing batteries to your terminal - SDP service cannot be disrupted.

VoIP providers like Vonage don't provide reliability guarantees, and thus aren't a complete replacement for a landline phone. They're limited to the relative unreliability of your internet connection. SDP is a competitor to the local phone company the provides reliability.

If your phone isn't working at all, contact Shaw immediately. They may know about the outage, but it never hurts to ask because it is a critical service (and Shaw will provide service levels to that effect). You might also want to bring in the old phone line from the phone company into the house as an emergency backup - a line that used to carry phone service must still carry a valid dialtone to call 911 even if the service is no longer provided.