Technical requirements to be provided by terminal equipment of the TFTS capable of, and intended for, connection to a public telecommunication network. TFTS will operate in the frequency band 1670-1675 MHz (ground to air) and 1800-1805 MHz (air to ground). The modulation technique is ?/4 DQPSK. The system is cellular in nature and the availablespectrum will support up to 164 radio channelswhich may be reused between cells. Each radio channel will support four voice telephone circuits operating with a 9,6 kbit/s voice coding alogorithm. The objective of this TBR is to define the minimum requirements for conformance testing of TFTS Aircraft Station (AS). This shall include testing of the radio interface in terms of RF parameters and basic interworking tests. The interworking tests include a set of tests over the CTU/AT interface which conform to ARINC 746 Attachment 11 characteristics. For non-ARINC 746 aircraft the TBR includes interworking tests based on the AT plus the terminal equipment configuration. This TBR covers the essential requirements of the TTE Directive 91/263/EEC Articles 4c, 4d, 4e and 4f. Articles 4a and 4b are subject to proof of conformity outside of the scope of this TBR and, therefore, are not covered by this TBR. Telephony for TFTS is not a justified case and therfore, there are no requirements on voice quality in relation to Article 4g of the TTE Directive. Certain aspects of EMC performance are the subject of normal aircraft eqipment certification and are specified in Eurocae ED14C (RTCA-DO160C). The applicable test categories are specified in ARINC Characteristics 752. It should be recognized that TFTS mobile stations are airborne equipment and that they are also subject to a separate certification process for aircraft. (DI/RES-05-01/4 (I-ETS 300 ...) constitutes the full conformance tests for TFTS. The set of requirements in I-ETS 300 and this TBR are not necessarily identical.