scope:

This European Telecommunication Standard (ETS) specifies the technical characteristics required for end-to-end interworking over the Public Switched Telephone Network (PSTN) of 14 400 bit/s, 12 000 bit/s, 9 600 bit/s, 7 200 bit/s and 4 800 bit/s duplex modems standardized for use over the PSTN, in accordance with CCITT Recommendation V.32 bis [1].

The objective of this specification, the application of which is entirely voluntary, is to provide the users with an added degree of assurance that modems in compliance with this specification, can interwork, with each other under most network conditions.

The term "modem" in the context of this ETS includes all physical implementation practices for a voice band modem, which is conductively connected to the PSTN.

This ETS specifies ten modes of operation, each with up to five modes of use (see subclause 5.2).

This ETS also contains descriptions of the tests to be performed in order to confirm compliance with the functional requirements contained herein. A general description of the test conditions and test requirements is given in annex A (normative).