The CT2 standard was originally adopted in 1987 in Great Britain and improved with a common air interface (CAI) in 1987. The CAI facilitates interoperability between equipment from different vendors while the original standard only guarantees non-interference. The CT2 standard is used in home and office cordless telephone equipment and has been used for telepoint applications [Goodman, 1991b].
CT2 operates in the frequency band 864-868 MHz and uses carriers spaced at 100 KHz. FDMA with time division duplexing is employed. The combined gross bit rate is 72 Kbit/s, transmitted in frames of 2 ms duration of which the first half carries down-link and the second half carries up-link information. This set-up supports a net bit rate of 32 Kbit/s of user data (32 Kbit/s ADPCM encoded speech) and 2 Kbit/s control information in each direction. The CT2 modulation technique is binary frequency shift keying.
