and and intelligent networks. 22.4.3.4 ETSI's structure BT, Business Telecommunications, responsible for private net- work signalling, subscriber installations and ISPBX intercon- ETSI's structure is shown in Figure 22.6. The General Assembly is nection. composed of representatives of members of the Institute, which may SPS, Signalling Protocols and Switching, which covers all be grouped into national delegations. Representatives from the EEC aspects of public digital switching and signalling, customer and EFTA have a special status as counsellors. The General Assem- access to ISDN, and test methods. bly is the governing body of the Institute, determining its policy, TM, Transmission and Multiplexing, which includes standards appointing the Director and Deputy Director, and approving bud- for cables and lines, multiplex and digital transmission and gets and accounts. digital radio relay. The Technical Assembly consists of members of the Institute, and TE, Terminal Equipment, covering all forms of equipment and is the highest authority within the Institute for the production and access, such as videotext, text, voice, message handling ser- approval of technical standards. It gives guidance to the Director on vice, ISDN terminal adaptors, and facsimile. 22/18 Telecommunication standards EE, Equipment Engineering, covering equipment practice. Standards are usually issued as European Telecommunication ATM, Advanced Testing Methods. Standards (ETS). These are similar to the European Standard (EN) HF, Human Factors. issued by CEN/CENLEC. An ETS is a voluntary standard, unless it is adopted as a NET, as described in the next section. In addition The permanent Secretariat is based in Sophia, Antipolis, France, ETSI issues Interim European Telecommunication Standards (I- which is the headquarters of ETSI and houses most of its project ETS). These are adopted when a standard is a provisional solution teams. It is headed by the Director, who is responsible for the and a more advanced standard is to be prepared, or a standar