(Total Access Communication System) An earlier analog cellular phone system deployed mostly in Europe and modeled after the AMPS system in the U.S. In the U.K., ETACS (Extended TACS) transmitted in the 871-904/916-949 MHz band, and International TACS (ITACS) and International ETACS (IETACS) operated outside the U.K. Narrowband TACS (NTACS) used the 860-870/915-925 MHz band and a narrower channel spacing that delivered more channels in the same amount of spectrum. See AMPS.
A 1G analog cellular radio derivate of the Advanced Mobile Phone Service (AMPS) technology, TACS was developed for use in the United Kingdom. TACS operates in the 900 MHz band and supports either 600 or 1,000 channels of 25 kHz, compared with the 666/832 channels of 30 kHz supported by AMPS.A number of variations were developed, including Narrowband TACS (NTACS), Extended TACS (ETACS), and Japanese Total Access Communications System (JTACS). TACS found acceptance in very few nations, largely has been replaced by GSM, and is considered obsolete in the United Kingdom. See also 1G, AMPS, analog, cellular radio, channel, ETACS, GSM, and NTACS.