Originally posted by: Haui
I got to thinking the other day about my cable modem. Essentially, the "data" is sent over a wire in electric nodes right? Do we provide the power on a consumer side (since our cable modem is plugged in) or does the cable company provide the electricity for it?
Crazy question, but somewhat interesting to discuss.
You both do. But don't worry, the electrons are recycled.
When you transmit data, your cable modem creates the EM wave that travels to the cable company's box. The power consumed in this process is trivial compared to the power your modem draws when plugged in to power but disconnected from the cable network. When data is sent back to you, the cable company's hardware generates the EM wave and they pay for it. They are also covering the costs of the equipment in their network, which are much more substantial.
Originally posted by: Haui
So why cant we develop something that plugs straight into the machine and by passes a "modem" and saves electricity?
Because the cable company's network uses a different communication system than any that your computer understands natively. The modem exists to act as a gateway, to stand in the middle and translate.
There is no technological reason that it would be impossible to just build DOCSIS support and an F connector into your motherboard (or a card, or whatever), but it would be less convenient (can't just connect another computer to your modem if you want to switch, if your PC goes down you have no internet access whatsoever). Something vaguely comparable has previously happened with cable TV, and is now (slowly) happening with digital cable as CableCard creaks into the market.
There's no real demand to integrate this stuff into the computer, though. Keeping it in a separate device makes upgrades possible as the standards change. It makes it easier to buy a new computer and hook it up. It makes it easier to set up a home network, which is increasingly popular. For motherboard makers, it's not a good value proposition: some people still have dialup, and even among broadband users you can't please everybody. DSL users see no benefit from built-in DOCSIS support, and vice versa. Building it into an expansion card instead is more hassle to install than a standalone modem and really not a big improvement.
