phone lines
phone lines
(OP)
I have a question about phone line polarity. I know it is refered to as Tip & Ring, but if I have a green and a red phone wire which is + and which is - for correct polarity? What is the AC voltage for a ring, and how many volts DC are on the lines normally? Do you guys find that some installations are polarity sensitive? Is ther a reason they call it tip and ring? Any info on this topic would be appreciated. When I determine + and - which goes to red on a wall jack and which goes to green on a wall jack? Pete






RE: phone lines
TTFN
RE: phone lines
RE: phone lines
Then your best bet is to measure the voltage when you are on-site. But, I would assume that if a phone is working on any line, it has the correct polarity.
TTFN
RE: phone lines
http://telecom.tbi.net/phone.htm
RE: phone lines
1 Phones are not polarity sensitive - at least not the European PSTN ones. And I think that that is true for US ones as well.
2 A pulse dialling system (which I think that you are referring to) acknowledges a call by reversing the line polarity. The station does this.
3 You ask why the terms Tip and Ring are used. The simple answer is that the old phone jacks were cylindrical devices with a Stem and a Tip. There was also a Ring between Stem and Tip. The Tip and the Ring were connected to the line and hence the designations Tip and Ring. Ring has nothing to do with Ring Signal. Which one could easily think.
Gunnar Englund
www.gke.org
RE: phone lines
RE: phone lines
Gunnar Englund
www.gke.org
RE: phone lines
RE: phone lines
RE: phone lines
RE: phone lines
tip is + and green
ring is - and red
At my house in the central U.S., I get 48.8VDC with green being + and red -, for whatever that's worth.
RE: phone lines
RE: phone lines
Gunnar Englund
www.gke.org
RE: phone lines
RE: phone lines
Gunnar Englund
www.gke.org
RE: phone lines
Ring is -48v (battery) and signalling lead.
For a 2 or 4 wire connection, the Tip is green, Ring is Red.
For 3-pair wiring, the Blue/White pair is the first line;
Tip is the group (white) wire for all pairs.
You gotta think like telco: ground is (+), working voltages
are (-), and the top/upper/first/outside terminal is ground.
Polarity is important to you only if you have a 2500 or
similar set (Touch-tone pad). These will not generate a
tone if polarity is reversed. Rotaries do not care.
In the last decade, polarity has become much less important
at the consumer level - most (all?) electronic phones, modems
and such have full-wave bridges in the circuitry.
<als>
RE: phone lines
RE: phone lines
RE: phone lines