Well, I'm not sure I want to get in the middle of an argument between the two of you, but I have to say that I think you're right and your son is wrong. Sort of.
Technologically, he's right that you can just plug a cable into a cable modem and have the capability of having a cable modem connection. The problem is, it's just like plugging a telephone into a wall outlet when the line isn't active: You have the connection, but you don't have the service.
On the other hand, you certainly don't need to go through America Online (AOL) to get cable service working, and, for that matter, you don't need digital cable. I'm with Comcast and my cable modem works fine (I"m using it right now) without the service supporting any sort of newfangled digital television signal.
So that's my compromise answer. You can plug a cable modem into a cable system but you can't actually use it until you sign up for cable modem service and have it enabled by the cable company.
Oh, and shop around. There are often quite different deals available in metro regions from competing vendors, and don't forget to double your antivirus, antispyware and firewall protection once you are hooked up since everyone in your physical neighborhood is then also often part of your "network neighborhood" too.
Good luck!
Sign up for my weekly AskDaveTaylor Newsletter and you'll receive even more tech and gadget help
right to your inbox, along with exclusive news and industry updates. It's good stuff. I promise!
It seems, though, that when subscribing to comcast cable AND broadband service you've opened their door wide open. After ending my cable service (but keeping the internet service) my roomate and I found that we still had digital basic cable channels. Perhaps that must stay open in order for the cablemodem to function? That was our best guess.