This EN specifies the technical requirements to be met by terminal equipment capable of connecting to a public telecommunications network and that support the HSCSD feature. These requirements apply to terminals for Phase 2+ of the public land mobile radio service, operating in the 900 MHz band with a channel separation of 200 kHz, utilising constant envelope modulation and carrying traffic channels according to the Time Division Multiple Access (TDMA) principle. This EN specifies the terminal equipment HSCSD requirements for the GSM 900 version of the Global System for Mobile communications (GSM). For each test purpose and its corresponding conformance requirement, a reference is given to the test method in EN 300 607-1 (GSM 11.10-1) [2]. The requirements apply at the air interface and the Subscriber Identity Module - Mobile Equipment interface for the access requirements, which may be stimulated to perform the tests by additional equipment if necessary. The measurement uncertainty is described in EN 300 607-1 (GSM 11.10-1) [2]. This EN covers the essential requirements of the Terminal Directive 91/263/EEC [1] Articles 4d, 4e, 4f. The Terminal Directive 91/263/EEC [1] Articles 4a and 4b are covered by other directives, and, therefore, not by this EN. In this EN, there are no Electromagnetic Compatibility technical requirements in terms of the Terminal Directive 91/263/EEC [1], Article 4c. NOTE 1:Technical Requirements for EMC performance and testing of the equipment are covered by the relevant standards applicable to the EMC Directive 89/336/EEC, annex A. This module specifies the HSCSD Terminal equipment additional requirements. EN 300 607-1 (GSM 11.10-1) [2] constitutes the conformance test suite for GSM. The verification of the conformance requirements in this EN is based on the tests described in this reference. The set of requirements in EN 300 607-1 (GSM 11.10-1) [2] and the set of requirements in this EN need not be identical. All the requirements in this EN are specific to mobile stations supporting HSCSD. An active accessory is covered by this EN if it modifies the terminal performance in an aspect which affects conformance to essential requirements. NOTE 2:Only active devices are subject to this EN. Accessories may be tested with specific terminals, and either approved for use with those terminals only, or may possibly be approved for use with a wider range of terminals, depending on the nature and effect of the accessory.