Yes this software does work with VoIP lines.
However here is the deal, the Vonage company doesn't like users using other hardware or software with their phone lines.. they're kind of mean and make you purchase their hardware for their line, even if you have other hardware (or sometimes even the same hardware) that would work perfectly.
Most VoIP providers are not like Vonage and they are open to BYOD (Bring Your Own Device) which allows IVM and other software from NCH like Axon to easily connect with them.
Does that mean there is no hope for using Vonage with IVM!? No! There is hope!
Method 1: Purchase a Voice Modem, connect vonage line to Voice modem
Advantages: Very cheap, ~$20. You may even already have one
Disadvantages: Quality not as good as other methods, but still acceptable
Method 2: Purchase a Voice Logic Board, not sure what they're called
Advantages: High quality, usually support many phone lines, with Carousel software may be able to interface with Axon
Disadvantages: Very expensive (compared to a normal Voice Modem)
Method 3: Purchase a Sipura 3000 or 3102 FXO adapter
Advantages: High quality, makes any normal or Vonage line into a VoIP line the computer can interface with, also can be used with Axon to have an even more advanced feature-full phone system
Disadvantages: More expensive than a voice modem, a little complicated to set up
Method 4: Buy a Vonage SIP line (Vonage lets customers purchase SIP lines that IVM and Axon can interface with)
Advantages: Would be perfect solution... but
Disadvantages: Vonage only offers an SIP line in addition to your current plan, you can't have just an SIP line. Also your SIP line is completely seperate to your Vonage line with a seperate phone number and seperate calling plan. No unlimited calling plan is available for Vonage SIP lines. So in summary, you would have to pay for two vonage lines, even if you only used one.