RJ-45 Wall Jack: Split for PC and Phone?

[Guest_imported]

I need some advice. I've wrestled with some wires, but have been unsuccessful thus far...

I have a PC (ethernet Cat5 cable to cable modem) and a phone in a room with one RJ-45 wall jack. The Cat5 cable from the jack runs to a central wiring closet (30 ft away) where it plugs into the router and cable modem. From the Internet, I've gleened that Ethernet only uses wires 1,2,3&6 and phones use wires 4&5 of an 8-wire cable. Shouldn't I be able to use both devices on the same cable? I've tried 8-wire dual plugs and connectors (careful to return the wires to their proper position -- i.e. using 3 cables and 2- straight 8-wire connectors) to split off the ethernet and phone (to a phone hub). I can only get one device at a time to work properly. Any suggestions besides running another cable?

 

[gunthnp]

well what happens is when you do this you get cross talk on the wires that why they are not working right So long and thanks for all the fish.

 

[MasterRacker]

To truly achieve CAT5 standards on a cable all 4 pairs must be connected. The extra pairs essentially "drain" excess noise. As gunthnp said, without the extra pairs, crosstalk increases.

The general TIA "golden rule" is "one cable, one connection". The CAT5 standard doesn't only define wire, it defines a system that consists of wire, jacks, plugs, punchdowns, wire fastening, bend radii, etc. All pieces must meet spec for 100Mhz or faster connections to be stable.
Jeff

I haven't lost my mind - I know it's backed up on tape somewhere ....