Hack your House: Run both ethernet and phone over existing Cat-5 cable

Step 5 Crimp phone jack and reassemble

At this point, you need to establish a standard way of wiring the phone jack. It is a completely arbitrary choice.

Here is how I did it:
Brown Striped Cat 5 -> Red Telephone
Brown Solid Cat 5 -> Green Telephone

Follow the instructions on your phone jack to crimp the brown pair into the red and green wire slots on the jack. This must be done in the same order on every connection (see above.) Use a knife to trim the extra.

Once this is done, reassemble the jacks using a faceplate with one additional hole.

This end of the connection is now done.

Comments

[elias.alberto]

I don't know how different are your phone landlines from the ones in Brasil, but what I've noticed is my phone will work regardless of the polarity of the wires. As long as I connect both, the phone works.

[Dranoweb]

Polarity does matter.
Most phone have polarity correction built in and hence you won't notice any difference on your phone, but your modem and adsl signals will suffer with reverse polarity.

Phone lines are 48VDC on idle, 90VAC on ring and around 30VAC when in use.

you can check with a multimeter but red should be negative (odd but true) and green should be positive.

If you have a second phone line, black is positive and yellow is negative.

[pcooper2]

Phone lines are -48 VDC open circuit. The ring signal is 30-34 VRMS superimposed on the DC, so the swing is roughly between ground and -96 volts.

The old 4-conductor, beige jacketed household telephone cables typically used red and green conductors for the first pair, although this is not true of CAT-5A cable which uses eight white wires with various color stripes. Wire pairs are twisted together in CAT-5A cables.

If you don't know what VRMS means, you have no business fooling with this stuff.