This section needs additional citations for verification. Please help improve this article by adding citations to reliable sourcesin this section. Unsourced material may be challenged and removed. ( April 2012) ( Learn how and when to remove this template message) West Germany had a network called A-Netz launched in 1952 as the country's first public commercial mobile phone network. In 1972 this was displaced by B-Netz which connected calls automatically. The first major change was in May 1990, when the London 01 area code was replaced with 071 and 081. Local numbers remained seven digits long. Exchanges in central London used the 071 code. The remaining exchanges now used the 081 code and formed a ring around the 071 area. [34] Although this effectively doubled the available numbers from eight to sixteen million, it was not to be the last change for the capital. January 1915: First transcontinental telephone call (3600 miles), with Thomas Augustus Watson at 333 Grant Avenue in San Francisco receiving a call from Alexander Graham Bell at 15 Dey Street in New York City, facilitated by a newly invented vacuum tube amplifier. [27]

A. Kling, Andrew (2010). Cell Phones. Farmington Hills, MI: Lucent Books. pp. 24–26. ISBN 9781420501643.January 1877: Bell's U.S. Patent No. 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell. Some RCC systems were designed to allow customers of adjacent carriers to use their facilities, but equipment used by RCCs did not allow the equivalent of modern "roaming" because technical standards were not uniform. For example, the phone of an Omaha, Nebraska–based RCC service would not be likely to work in Phoenix, Arizona. Roaming was not encouraged, in part, because there was no centralized industry billing database for RCCs. Signaling formats were not standardized. For example, some systems used two-tone sequential paging to alert a mobile of an incoming call. Other systems used DTMF. Some used Secode 2805, which transmitted an interrupted 2805Hz tone (similar to IMTS signaling) to alert mobiles of an offered call. Some radio equipment used with RCC systems was half-duplex, push-to-talk LOMO equipment such as Motorola hand-helds or RCA 700-series conventional two-way radios. Other vehicular equipment had telephone handsets and rotary dials or pushbutton pads, and operated full duplex like a conventional wired telephone. A few users had full-duplex briefcase telephones (radically advanced for their day) Just as modernisation of Torquay's area has seen 14 STD codes merged into one, the move to linked numbering areas across the country has led to about 5,600 remaining exchanges [17] being covered by 658 [18] dialling codes, and local codes no longer exist.

Both BT and Mercury issued only 10-digit freephone numbers to users after 1997. [44] With the market opened up to competition, many other companies also allocated these numbers to users. October 1876: Bell makes the first two-way long-distance telephone call between Cambridge and Boston, Massachusetts. Edison, Thomas A. 1880. The Speaking Telephone Interferences, Evidence for Thomas A. Edison. Vol. 1 (jpg image), [cited 21 April 2006]. The Wireless Association Announces One Universal Charger Solution to Celebrate Earth Day". CTIA (Press release). 22 April 2009. Archived from the original on 14 December 2010 . Retrieved 22 June 2010.Lane, Clare (17 June 2009). "John F. Mitchell, 1928–2009: Was president of Motorola from 1980 to '95". Chicago Tribune. Archived from the original on 6 July 2009 . Retrieved 29 July 2009. Other codes had multiple uses over the years. For example, 0500 was originally assigned to a 'ring' of exchanges around Edinburgh which were moved to the 031 linked numbering scheme (0131 after PhONEday); some years later, 0500 was used for Mercury Freephone services.

On " PhONEday", 16 April 1995, the digit "1" was inserted into all UK geographic area codes, including those in the director, all-figure dialling, ELNS and mixed areas. Under the new changes, for example, Inner London's 071 became 0171; Outer London's 081 became 0181. A small selection of the codes that changed are shown in the table below: Advances in mobile telephony can be traced in successive generations from the early "0G" services like MTS and its successor Improved Mobile Telephone Service, to first-generation (1G) analog cellular networks (1979–), second-generation (2G) digital cellular networks (1991–), third-generation (3G) broadband data services (launched commercially in 2001) to the fourth-generation (4G) native-IP networks (launched in 2006 in South Korea). 5G began deployment in 2019. The original concept was for there to be a nationwide Director system, and in common with the Director system, Group Switching Centres were originally based in major towns and assigned codes based on two letters of the respective place's name and the corresponding numbers on a telephone dial. The letters and numbers originally corresponded as follows on a UK telephone (note that US and modern UK telephones use a different allocation of letters to numbers): February 1876, about 11:30 am: Bell's lawyer brings to the same patent office Bell's patent application for the telephone. Bell's lawyer requests that it be registered immediately in the cash receipts blotter. In 1995, the 070 prefix began to be allocated for personal numbers (PNS). These new numbers had 10 digits. [37] Number rangeIn 1995, the United Kingdom adopted the pan-European 112 emergency services number. This new number runs alongside the existing 999 number, first introduced in 1937. July 1875: Bell uses a bi-directional "gallows" telephone that was able to transmit "indistinct but voice-like sounds" rather than clear speech. Both the transmitter and the receiver were identical membrane electromagnet instruments. The longest telephone numbers in use until now had been 9 digits long (not including the 0 trunk code), e.g. 051 234 5678, 0303 456789, 03873 56789, 0800 445566. The long term plan is for migration to 10 digit numbering in the UK and in 1991 this started with new 0800 numbers being allocated with 10 digits.