This European Telecommunication Standard (ETS) defines the requirements for the transceiver of the pan-european digital mobile cellular and personal communication systems operating in the 900 MHz and 1 800 MHz band (GSM 900 and DCS 1 800). Requirements are defined for two categories of parameters: - those that are required to provide compatibility between the radio channels, connected either to separate or common antennas, that are used in the system. This category also includes parameters providing compatibility with existing systems in the same or adjacent frequency bands; - those that define the transmission quality of the system.