Diff b/w two wire modem and four wire modem

hi all,

What is the diffrennce between two wire and four wire Modem..?

The number of wires?

Hi Skepticals,

Ya, wire is difference........ but where we have to use two wire and where we have to use Four wire modem.....

What is the function diference........?

I think the two wire ones are generally used in your home but the 4 wire ones are used in more advanced telephone systems in use in some offices. I know that where i used to work they had 4 wires.

Anything mroe than that i am afraid i am not sure.

Cheers

The two-wire system uses a single pair (two wires) for both the transmitted and received audio signal; either as a sort of audio half-duplex or by frequency-shifting one band so it does not interfere with the other. A four-wire system uses a pair for receive and a pair for transmit, four wires in all. By physically separating the two audio streams the crosstalk is greatly reduced and you can better optimise the line for lower distortion, lover noise and a flatter frequency response. You'd want these advantages, for example, in an audio line used for a broadcast feed but you'd do without them for a domestic telephone which typically uses just the two lines. A four-wire modem therefore is designed for driving a link over a four-wire circuit to the modem at the other end. You can, however get four-wire to two-wire converters if you need them but to be honest just buying another modem will be cheaper