How does xDSL work

xDSL technology assumes digital data does not require change into analog form and back. Digital data is transmitted to our computer directly as digital data and this allows the phone company to use a much wider bandwidth for transmitting it to you. Meanwhile, if one chooses, the signal can be separated so that some of the bandwidth is used to transmit an analog signal so that you can use your telephone and computer on the same line and at the same time.

In detail, xDSL utilizes more of the bandwidth on copper phone lines than what is currently used for plain old telephone service (POTS).  By utilizing frequencies above the telephone bandwidth (300Hz to 3,400Hz), xDSL can encode more data to achieve higher data rates than would otherwise be possible in the restricted frequency range of a POTS network.  Thanks to Advances in DSP technology combined with innovation in algorithms and coding methods over the past few years, bandwidth utilization has increased even more (varying from under 100kHz for narrow-band ISDN to over 10MHz for VDSL).

In order to utilize the frequencies above the voice audio spectrum, xDSL equipment must be installed on both ends and the copper wire in between must be able to sustain the higher frequencies for the entire route.  This means that bandwidth limiting devices such as loading coils must be removed or avoided.

Next: xDSL Modulation Technologies