Total Access Communication System

"TACS" redirects here. For other meanings of "TACS" or "Tacs", see Tacs.

Total Access Communication System (TACS) and ETACS are variants of Advanced Mobile Phone System (AMPS) which were announced as the choice for the first two UK national cellular systems in February 1983, less than a year after the UK government announced the T&Cs for the two competing mobile phone networks in June 1982.^[1] This 1G technology is now obsolete.

First-generation Motorola 4500X mobile phone, which utilised ETACS

History

Vodafone (known then as Racal-Vodafone) opted for a £30 million turnkey contract^[2] from Ericsson (ERA) to design, build and set up its initial network of 100 base station sites.^[3]

Vodafone used CMS8810 equipment designed by Ericsson some of which was made under licence by Racal Carlton Nottingham

Cellnet (then known Telecom Securicor Cellular Radio Ltd) used development labs in the facilities at General Electric (later made part of Motorola) based at Lynchburg, Virginia, United States. The reason Cellnet used the General Electric labs was because the AMPS system was already in development there, and the company had set up a production facility in readiness for AMPS production in 1985 which the Cellnet TACS was to share. In March 1984 development of prototypes began at General Electric. Production began in 1985 and General Electric produced 20,000 systems that year for Cellnet's distribution in the UK. Production of what was to become the Motorola model were then made at Stotfold, Bedfordshire, England. This production facility continued making TACS until the advent of GSM.

TACS cellular phones were used in Europe (including the UK, Italy, Austria and Ireland) and other countries. TACS was also used in Japan under the name Japanese Total Access Communication (JTAC).^[4][5] It was also used in Hong Kong.^[6] ETACS was an extended version of TACS with more channels.

TACS and ETACS are now obsolete in Europe, having been replaced by the GSM (Global System for Mobile Communications) system. In the United Kingdom, the last ETACS service operated by Vodafone was discontinued on 31 May 2001, after 16 years of service. The competing service in the UK operated by Cellnet (latterly BT Cellnet) was closed on Sunday 1 October 2000.

Eircell (now Vodafone Ireland) closed its TACS network on 26 January 2001. This followed a long period during which customers were encouraged to switch to GSM services. When the network was closed, there were very few, if any, active TACS customers left. Customers who switched network were able to keep their phone number, but the (088) prefix was changed to either 087 (Eircell, now Vodafone Ireland) GSM or 086 (Esat Digifone, which became O2 Ireland before merging with Three) GSM. At the time, full mobile number portability was not available to TACS customers and the (088) prefix was closed. An automatic voice message was left in place for 12 months advising callers of the customer's new prefix.

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

TACS BAND Summary

Base TX Start	End (MHz)	Mobile start	End (MHz)	Band
935	950	890	905	TACS 600 Channels
935	960	890	915	TACS 1000 Channels
917	950	872	905	E-TACS 1320 Channels

ESNs were issued in batches of 65535 by BABT for phone manufacturers to program into each cellular phone to make each one unique to the TACS network with which it attempted to register.

The following countries had more than two batches of ESNs allocated to them: UK, Italy, Austria, China, Malaysia, Hong Kong, Singapore, Bahrain, UAE, Kuwait, Philippines, Sri Lanka, Australia.

UK ETACS and US AMPS compared

Feature	TACS	AMPS
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	10000 Hz
Mobile TX pwr MAC 0	10 W	4 W
Mobile TX pwr MAC 1	1.6 W	1.6 W
Mobile TX pwr MAC 2	630 mW	630 mW
Mobile TX pwr MAC 3	250 mW	250 mW
Mobile TX pwr MAC 4	100 mW	100 mW
Mobile TX pwr MAC 5	40 mW	40 mW
Mobile TX pwr MAC 6	16 mW	16 mW
Mobile TX pwr MAC 7	6.3 mW	6.3 mW

Commercial deployments

Country	Operator(s)	ƒ (MHz)	Launch date	End of service	Notes
United Kingdom  Jersey	Vodafone Cellnet Jersey Telecom		Jan 1985 Jan 1985 1987	May 2001[7] Oct 2000 1999	[8]
Ireland	Eircell		Dec 1985	Jan 2001	[8]
Hong Kong	CSL Mobile Hutchison Telecom		1987	May 1996[9]	[10][11]
China	China Mobile		Nov 1987[12]	Dec 2001[13][14]	[15]
Macau	CTM		Nov 1988[16]	Feb 2001[17]	[18]
Sri Lanka	Celltel		1989	2006[19]	[18]
Japan	DDI		Jul 1989[20]	Sep 2000[21]	[18]
Malaysia	Celcom		1989		Named ART-900.[22][18]
Mauritania			1989		[18]
United Arab Emirates			1989		[18]
Ghana					[23]
Bahrain					[23]
Kuwait					[23]
Italy	TIM [en; it]		Apr 1990	Dec 2005[24][25]	[8]
Spain	MoviLine [es]		Apr 1990	Dec 2004[26]	Named TMA-900.[8]
Austria	Mobilkom		Jul 1990	Feb 2002[27]	[23]
Malta					[23]
Nigeria			1991		[23]
Singapore			1991		[23]
Kenya			1992		[23]
Mauritius					[23]