Is this the 'Tip & Ring' of the telephone system?

[foTONICS]

Hey all,

I am currently a student in telecommunications. I was painting my room and hence removed all the cover plates. One of them was a telephone jack and inside it there was a red, green, yellow, and black. I'm pretty sure the red is the -48VDC and the green is ground. What are the yellow and black wires, some sort of data for dial up or DSL? I've attached a photo for reference.

-Thanks again guys!

 

[davenn]

the red and green are the normal 2 wires used for a phone line
there's always spare wires in a cable

Dave

 

[peter.mitchell]

most telephone cables are run with at least 2 pairs, a phone signal pair and a power pair, these days since more handsets draw power from the mains, via a small adapter, the power pairs are not needed, just the phone signal pairs.

usually, the pairs for the phone signal are:
blue/white
blue-white/blue
green/yellow

and the pairs for power are
red/black
red/brown

in your case, it appears you only have one, non-standard pair (green/red), because of this i can fairly safely say it is the phone signal pair, and i can see 3 wires going into each junction, implying that one set goes to your socket on the wallplate, one pair goes to another socket, and one pair goes to the lead-in or an alarm system.

telephones haven't used a TRS [(tip, ring, shield/sleeve)phone] connector in a long time, they are similar to the connectors you see on microphones and headphones, generally only larger, more information can be found about it here: http://en.wikipedia.org/wiki/TRS_connector

 

[TedA]

FoTonics,

You failed to reveal your location, which matters in this case.

Your colors appear to be Bell System standard, where red and green are used first, and yellow and black are spares, or used for a second line.

I don't think they had Bell in Australia; Mr. Mitchell's colors are likely the non-standard ones where you are located.

Ted

 

[davenn]

actually red and green were/are the standard phone line colours in Australia as well.

Dave

 

[peter.mitchell]

actually red and green were/are the standard phone line colours in Australia as well.

Dave

Not for the past 12+ years it hasn't, and on the lead in even longer.

also, yeah, i just assumed, and as you know, assumeing makes an ass out of u and me.

 

[davenn]

Not for the past 12+ years it hasn't, and on the lead in even longer.

also, yeah, i just assumed, and as you know, assumeing makes an ass out of u and me.

I'm, like the OP, are talking about home phones which still use the centre 2 wires red and green in the modular plug.
Even my brand new printer, which has FAX facility, comes with a modular cable and it wired red/green

Of course its a whole different ball game for office systems that are digital and these days I.P. based and usually 4 wire

New Zealand went to the BT connector and cabling system in the mid 1980's, we spent years upgrading old cabling in homes to the new style

D