I had a regular phone line but the only purpose for having that line was for sending faxes, which only happens a few times per month. So, naturally, I felt it was a waste to be paying so much money for it.
I purchased the SPA 112 and configured it to use with VoiceNetwork.ca. I was successfully able to send faxes.
I later cancelled my phone number and switched my internet to cable (since I was on DSL before).
I can no longer successfully complete a fax ever since I switched to cable internet. I don't know why because the speed is 3 times faster upload and 5 times faster download.
I'm guessing there is a setting that needs to be changed in the ATA admin panel to adjust for cable internet.
My configuration settings are attached as screenshots.
Firmware: 1.3.2-XU (014) Jul 2 2013