xDSL is a name of a technology family where digital modems are used with ordinary telephone wires. The kind of digital system that is transmitted on the wire is shown by the letter that replaces "x". Examples are ADSL (asynchronous) SDSL (synchronous) and VDSL (Very high speed). If ADSL is used for the fixed connection to the internet the ordinary telephone network is used for the transmission. You can still use your telephone to make telephone calls while you are connected. To be able to use an ADSL connection you must have an ADSL modem and the local telephone station must be upgraded for the service. The service varies from 256 kbit/s up to 24 Mbit/s in download speed.