Probably a really dumb question...but so am I

Question

Just bought a brand new iMac (specs below). Old one? Panther (3.10.9), 1 GHz, 2 RAM, 80 GB space)
Keeping the old iMac. A perfectly good machine. Only reason I bought a new one: kind of maxed out regarding my primary use of a computer...home music recording. Just needed more space, power, speed, etc.
Question: Before I call the phone company (our ISP: ATT), want your advice.
Can I just hook up two computers (both iMacs, one old, one new), on the same telephone line (a land line...this would be the only phone line coming into the house), and have them work? Or, would the ISP, the telephone company, charge us more for doing this? Meaning operating two computers on the same line simultaneously. (Forget about wireless here. Don't use it, not sure that I will anytime soon.)
Why couldn't I just plug in the other computer into a phone jack in another room in the house and have it work while the other one, in another room but using the same phone line, is running at the same time? Both simultaneously. (Sure, I'd need a modem for each machine going into the ethernet port.)
As I said, possibly a dumb question. On the other hand, I'm pretty dumb too.
Thoughts, advice, suggestions? Greatly appreciated.

Answer 1

It's probably connecting to a broadband modem (DSL or ADSL). That device allows you to get the high speed internet going on using the same phone jack in your house, and connects to the computer through an ethernet cable.
"Old school" or dial-up modems are traditionally built into the computer or plug into a USB port, and then use a normal phone cord (same thing other phones in the house use). Aside from being super slow, your line is usually busy and you're unable to make/receive calls when you're online.
I'm guessing you're connecting to a broadband modem (since you mentioned ethernet cable). With that in mind, the answer is yes, you can hook both those computers up so they can be online at the same time. What you need is what's called a router or switch, and they're not very expensive. One line connects to your broadband modem, then you have 3-4 jacks that you can plug additional computers in (so they can all use the connection at once).
If you want to have the machines in different rooms but don't want to run wires everywhere, look for a wi-fi router, which will usually give you a few jacks for connecting computers that don't have wi-fi but will also let you do a wireless internet hookup for your new iMac, the old one (if it has wi-fi), and even iPhones if you have 'em.
Apple has two products that might work for you. The Airport Extreme Base Station has super-fast wifi plus jacks for plugging computers in via ethernet, and even lets you share a printer. http://www.apple.com/airportextreme/ The Time Capsule does all that, and also has a built in hard drive (you can get with a 1TB or 2TB hard drive), which is great for using Time Machine. We've had a Time Capsule since they first came out and love it - super easy to set up, and all the backup stuff just happens without having to worry about it.
Hope that helps!