scope:

The present document specifies requirements and test methods for the low pass and high pass parts of xDSL over ISDN splitters and for xDSL over "ISDN or POTS universal" splitters.

• The xDSL over ISDN splitters allow only ISDN underlying the broadband xDSL band.

• The xDSL over "ISDN or POTS universal" splitter shall support either POTS or ISDN transmission underlying the broadband xDSL band.

These splitters are intended to be installed at the Local Exchange (LE or network) side of the local loop, either at the LE or at a remote cabinet, and at the TE (i.e. user) side near the NTP. In the case of splitters at the TE side, the present document specifies the "central splitter" (also called "master splitter") that is intended for use at the demarcation point of the customer premises.

The present document covers the following xDSL variants: ADSL, ADSL2, ADSL2plus, VDSL1 and VDSL2, defined in the relevant ITU-T documents listed in informative references and the bibliography.

The splitter filter, as specified by the present document, may be implemented as an independent unit, separately from the xDSL transceiver, or may be integrated with the xDSL termination unit. The splitter may also be integrated with the base band termination unit (e.g. POTS or ISDN line card). However, this is outside of the scope of the present document.