This has nothing to do with Vonage and likes that market to consumer - their devices are locked so the consumer is locked into the services that Vonage/MagicJack/etc provides. They are not the companies that are going to eat lunch of cable companies and old school telcos as their business model is to sell the same servie at a minimum discount to the rates of dominant carriers.
What the cable companies are afraid of is that when a consumers have SIP speaking devices used to terminate calls the consumers will find VOIP providers that charge $1.00 a month for a phone number and another $0.01457 per voice minute with 6, 5, 4, 3, 2 or 1 second billing. After deploying about nearly a thousand SIP-speaking phones for different folk over last few months I can tell you that the self-provisioning for the customer's side is becoming so easy a caveman can do it.
There goes their $20 or more per month worth of profit per phone number.
First its indisputable that voice is inexpensive and will become less expensive, from all providers that stay in the business, over time. Having said that, perhaps you might want to look at both Skype & MagicJack since their pricing ranges between free to extremely inexpensive. MagicJack does require an adapter designed for them, but that seems to mainly be because they are targeting the very low technical skill market specifically. Skype (and clones) of course run on multiple devices ranging from SOHO 3rd party adapters to PCs to smart phones. MagicJack charges $19.99 per year for unlimited US and Canadian calling(and it appears to really be unlimited http://blogs.computerworld.com/voip_quiz_how_many_minutes_in_an_unlimited_pl...). While Skype and MagicJack have attracted users (so has Google Voice which is also free) they haven't eroded the VOIP take rates for the cable operators in significant numbers. I would suggest that this has nothing to do with the fact these services/devices don't inter-operate with PacketCable networks and more to do with customers liking bundles and generally believing that the cable offering is a good deal even if its not the cheapest offering.
Does it mean that they are preventing other SIP devices to work on their IP network? No, it does not. But what they are doing is preventing SIP devices from working with their voice network because they do not want it to be a user-controlled SIP device.
Alex
Exactly how are they preventing anything? This is like someone yelling that they have designed a car that is 14 feet wide and the government is preventing them from being able to drive on the existing roads which by standard are only 12 feet wide (some older roads are much narrower). -- Scott Helms Vice President of Technology ISP Alliance, Inc. DBA ZCorum (678) 507-5000 -------------------------------- http://twitter.com/kscotthelms --------------------------------