Definitions

communication system

Total Access Communication System

Total Access Communication System (TACS) and ETACS are mostly-obsolete variants of AMPS which were used in some European countries (including the UK & Ireland in 1983). TACS was also used in Japan under the name Japanese Total Access Communication (JTAC). It was also used in Hong Kong . ETACS was an extended version of TACS with more channels.

TACS and ETACS are now obsolete in Europe, having been replaced by the GSM system. In the United Kingdom, the last ETACS service operated by Vodafone was discontinued on 31 May 2001, after sixteen years of service. ETACS is however still in use in a handful of countries elsewhere in the world. NMT is another analog cellular standard that was widely used in Europe, mainly in the Nordic countries, which has now been fully replaced by GSM except for limited use in rural areas due to its superior range.

Frequency bands used by ETACS in the UK

Channel Cell TX (MHz) Mobile TX (MHz) Notes ..............
1 935.0125 890.0125 25 kHz spaced channels
23 935.5625 890.5625 1st of 21 dedicated vodafone control channels
24 935.5650 890.5650 2nd of 21 dedicated vodafone control channels
300 942.4875 898.0625 9.5 kHz peak speech fm deviation
323 943.0625 898.0625 1st of 21 dedicated cellnet control channels
600 949.9875 904.9875 last TACS channel, ETACS extended this to 1320 later
0

UK ETACS and USA AMPS compared

Feature TACS AMPS Notes ..............
Channel Spacing 25 kHz 30 kHz
Speech peak Freq Dev 9.5 kHz 12 kHz
Signalling FSK peak Freq Dev 6.4 kHz 8 kHz
Signalling rate 8 kbit/s 10 kbit/s
SAT 0 5970 Hz 5970 Hz
SAT 1 6000 Hz 6000 Hz
SAT 2 6030 Hz 6030 Hz
ST 8000 Hz
Mobile TX pwr MAC 0 2.82 W
Mobile TX pwr MAC 1 1.12 W
Mobile TX pwr MAC 2 447 mW
Mobile TX pwr MAC 3 178 mW
Mobile TX pwr MAC 4 70.8 mW
Mobile TX pwr MAC 5 28.2 mW
Mobile TX pwr MAC 6 11.2 mW
Mobile TX pwr MAC 7 4.5 mW

References

BT Engineering Journal Vol 4 July 1985

Smith Myers ART 775 User Manual

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