Terminal equipments of xDSL (Digital Subscriber Line) are specially designed to allow better use of the potential of copper in the access network infrastructure. A common feature of these systems is relatively high transmission speed in the order up to tens of Mbit/s. Digital subscriber lines can be classified according to various criteria. One major division is according to a method of transmission to digital transmission connections in:
In the case of purely metallic solutions of the access network, where the connection to the provider terminating near the main distribution exchanges, can use ADSL, SHDSL and on limited distance also second improved generation ADSL2+ and VDSL. In the case of hybrid optical and metallic access network solutions, where there are facilities at the provider of extended closer to the subscribers can take full advantage of connections ADSL2+ and VDSL2 and G.fast.