Phone lines?

Question

If you touched a phone line would it kill you?

Why are some so thick they look like snakes?

When the lines move, that means it's busy...what about other methods of phone use..so 3-way..do the lines do anything

Answer 1

When the line is idle you will normally see about 50V DC across it.  That voltage drops when you go off-hook, the level being dependent upon the phone, the length of line from the exchange, etc.   A ringing line generally has the 50V DC WITH 90V-ish AC superimposed.    

Some pairs of wires in some cables may be carrying higher voltages though.  For example, here in the U.K. we have a pair-gain system (used to run more than one subscriber's phone on the same line) where power is delivered from the exchange out to the units on the poles at 140V DC.  

As for large cables, they just consist of many pairs of wires.  You can have a cable with anything from one pair right up to several hundred pairs.

Answer 2

no. The phone line has about 20 volts DC on it until the phone rings and then the ring voltage jumps to 90 volts AC... that will get your attention!

The thick cable is 25 pair, it is about 1/2 inch. The 6 pair is about 1/4 inch and the 3/16 inch is the typical residential 2 pair. Thicker the cable, the more multiples of 25 pair bundles.

Three way calling is the function of the central office. The lines only carry voltage and current (signalling etc) the rest is the function of the Central Office.