Modem Connection with VoIP
From DVRpedia
Overview
VoIP services such as Vonage are not compatible with high speed analog modems, such as the one included in Series 1 and Series 2 TiVos. To get the modems to connect, it is necessary to either slow down the modem or call a number with a slow modem on the other end. Configuring your VoIP service may help as well.
Details
Try the following settings in you TiVo Options menu:
Dial-In Number: 2129203005 Dial Prefix: *99, Call Waiting Prefix: *70, Phone Available: Off Dial Tone Detect: Off
Note: the *99 prefix sets the Vonage ATA device to data-optimized mode, making the call more likely to connect.
Note: Some people seem to be able to connect better to a New York (212) area code.
Additional Dial Prefix that Might Slow the TiVo Modem
Some people have had success with adding additional prefix commands so the TiVo modem drops to a slower speed. This sometimes does not work because the VoIP provider detects these tones, causing the call to not complete. One of the following dialing prefixes may work for you, or it may not, so give it a try and see. Try adding one of the commands to the beginning of the dial prefix shown above:
,#019, ,#034,