Is there such a thing as an internal cable modem? I've never seen one and I am wondering why there do not appear to be any.

Because cable companies do not make computers. Just money from their users.

I'd assume it's partially due to how common routers are now, but since most people get their modem from the ISP and they don't want to get into peoples' computers physically, that probably is a large part of it too.

Cable modems take a coaxial cable connection and convert it to internet via ethernet and VOIP phone via phone cable. They also have a number of status lights on them, and they are typically owned by the cable company (just on loan to the individual user). The cable companies don't want their property to be installed inside someone else's computer, and they want you to be able to see the blinking lights when you call tech support.

Actually, when I got cable broadband years back I bought the modem from my provider (Charter). Years later I ended up buying a new cable modem from Best Buy and installed it myself. A call to Charter was all it took to get my new modem on the broadband service. In either case I was the one who owned the modem not the provider.

I did not consider the possibility that a portion of cable broadband customers may not be the ones who actually own the cable modem.

I too owned my own cable modem for quite a few years, until I opted for Comcast's 'net/VoIP combo and then I had no choice but to rent from them.

Most people simply rent from their cable provider as they're not as technically savvy as the group here, even tho' it is pretty straightforward to configure yourself.

In the early days there were some PC-insertable cable modem cards, but as Joe cites the cable providers became ever more concerned with having to troubleshoot the myriad of problems that personalized PC configurations bring to bear.

And as also already cited most folks that are savvy have routers and therefore an external cablemodem at the point of service entry is the way to go.

i've seen a few, but they are expensive...

and they are designed for server racks so they 99% of the time wont work in regular AT/ATX Cases.

Another point is that the companies like to do software updates once in a while, and if the PC is off, the external modem is still under power and connected.

And also, for authentication, they used to check the system MAC adress on the NIC connecting the modem, so that only one system could use the connection. That also would have made internal installation a problem.