Data transmision on the telephone line

[froten]

I would like to know how data (didgital data specialy) are sent on the tephone lines? is it sent as analog or digital or some sort of modulation?

 

[m_llaa]

Salam
It depend on u. It is looklike another transmision line. u can send data with analog or digital modulation, but digital is common today. for example broadband internet connection like ADSL use telephone line and use digital modulation i think QAM.

 

[zolam]

it depends what do you understand by digital data transmission
usually phone lines are long ones and the copper tiles are interrupted by some kind of trafos so you cannot look at them like to "bus" logical data
usually we send defined frequencies for, discret or in packets - each frequency representing some coded information.
from the early days of 103 standard or telegraph when we sent two frequencies, one for 0 and one for logic 1 (usually about 2020 and 2220 Hz), nowdays we use different coding methods and packets, and in VDSL transmissions you can get over 8MBPS (megabit per second) using modulation techniques of course
if you want more info, just let me know and i ll be more specific