its stake in CWC's consumer operations to NTL (now Virgin Media) in 2000. Operations Payphones and mobiles From 1986 Mercury operated public payphones in the UK, in competition with BT. These proved not to be profitable and this interest was sold in 1995. They were notable for their varied designs which imitated architectural styles. Mercury also operated the first GSM 1800 mobile phone service, launched in 1993 as Mercury One2one. The service was first rolled out in the London area bounded by the M25, and offered free mobile to landline calls at off-peak times, weekends and Bank Holidays. Calls could be made free to landlines in the area the mobile was in, and to adjacent landline exchange codes. Even after this plan ceased being sold, SIM cards that were subscribed to the plan continued to provide these free calls, and often changed hands for large sums of money. Coverage was extended throughout the decade, with most of the UK having service by 1997. One2One was sold to Deutsche Telekom in 1999 for £8.4bn, and was rebranded as T-Mobile in 2002. Fixed-line phone services Mercury began by offering fixed-line facilities direct to business and residential customers. Callers could use the 'Mercury 2300' service via their existing BT phone line by dialling a '131' prefix followed by a ten-digit customer code, then the number they wished to dial. Some phones were manufactured with a 'Mercury button' which allowed the prefix and customer code to be stored and then dialled with a single button press. Later, a more modern indirect service was introduced which required only the dialling of an access code (132) and the destination number. Mercury also provided backbone services to the emerging British cable operators which were beginning to offer their own fixed-line telephone services. Mercury moved into the Private Branch eXchange market in 1990 as a result of Telephone Rentals being bought by Cable & Wireless. This enabled the Smart Box to be connected to a large number of TR's customers, so traffic was routed away from BT onto Mercury's network. Mercury pulled out of the PABX market in 1996, when it sold that part of the business to Siemens, creating Siemens Business Communication Systems (SBCS), which later became Siemens Communications. In 1997 the Mercury brand ceased to be and it was amalgamated into Cable & Wireless Communications. The consumer arm of the latter would eventually be bought out