I'm pretty sure the phone in the bedroom, is just an extension to the main phone line.
In that case moving the modem would be fairly pointless and might result in a lower connection speed. Line length = speed (roughly speaking) so requiring the telephone signal to travel through several additional metres of extension wiring to get to the modem is unlikely to be a good idea. At the very least you'd need a filter like you would with ADSL and frankly it's just asking for trouble. No, you want the cable connecting the modem to the phone socket to be as short as possible. Now what comes out the 'house end' of the modem is a different kettle of fish. The signals in that cable will travel a long way without deterioration so those cables can be almost as long as you want.
It still feels like we're talking at cross purposes though as on the face of it this just a typical every day networking question. With a typical FTTC installation you have:
<phone socket> - <modem> - <router> -{ your network }
(In fact this configuration can exist with ADSL as well although most installations combine the <modem> and <router> into one box.)
You seem to be asking how to access { your network } in your bedroom so the most common options (in rough order of preference as regards performance and reliability) are:
1. Run some CAT cable from one of the spare ports on your router up to your bedroom.
2. Buy some powerline adaptors. Connect one of the spare ports on your router to one of the adaptors, plug both one adaptor into a power socket near the router and plug the other into a socket in your bedroom. Now run a CAT cable from the bedroom adaptor to your computer. The two adaptors will talk to each other through the house power circuits.
3. Use wifi. In most houses the wifi from your router will already reach the bedroom. If not you can get wifi extenders that work like the powerline adaptors. If the machine that needs access is a desktop you'll need to buy a wifi network card (USB ones do exist).
Slightly less common would be to extend the CAT cable currently connecting your modem to your router and thus relocate the router to your bedroom. But that would be a bit odd. If you're going to lay cable you can save yourself some bother and just run a cable from the router to wherever you need it.
Edit: It occurs to me that perhaps you don't have a router. That's not a very good configuration in the first place in that case the above solutions will work but just replace 'plug into spare port on router' with 'plug into modem'. You'd basically just be allowing your computer to be further from the modem.
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Andrue Cope
Brackley, UK
Edited by Andrue (Wed 05-Feb-14 14:54:52)