The format used one mono audio subcarrier, which was normally allocated to an additional audio track or radio station, or one channel of a stereo audio track/station. The carrier was digitally modulated and carried a 192 kbit/s, 48 kHz sampled MPEG-1 Layer II (MP2) encoded signal. 9.6 kbit/s was available for data.
Special receivers were required to listen to ADR stations, although some combined analogue/digital satellite boxes and later standard analogue boxes were equipped to decode it.
ADR was succeeded by DVB-S, with which it is incompatible, despite both being transmitted using MP2 and generally at the same bitrates. As a result, when the final analogue switch-off on the Astra 1 satellites occurred, ADR became obsolete.
The majority of the channels to have been broadcast using ADR were in the German language.[1] Because of this, the system can in a way be seen to have replaced the German Digitales Satellitenradio system, dating from the 1980s, which used an entire satellite transponder to carry 16 NICAM[2] encoded radio stations, and which closed in 1999.