A cellular telephone switching plan was described by Fluhr and Nussbaum in 1973, [23] and a cellular telephone data signaling system was described in 1977 by Hachenburg et al. [24] Emergence of automated services [ edit ] Code of Federal Regulations: Telecommunications. Washington, DC: Office of the Federal Register. 1 October 1992.

In 1991 the first GSM network ( Radiolinja) launched in Finland. In general the frequencies used by 2G systems in Europe were higher than those in the United States, though with some overlap. For example, the 900MHz frequency range was used for both 1G and 2G systems in Europe, so the 1G systems were rapidly closed down to make space for the 2G systems. In the United States, the IS-54 standard was deployed in the same band as AMPS and displaced some of the existing analog channels. At the same time, international direct dialling was being introduced and as other countries (such as the US) had different assignments of letters to digits the opportunity for confusion existed. An earlier modification to get round this problem for European dialling was the addition of the letter Q to the digit 0, which previously represented only the letter O. This was because some French exchanges had alphabetic codes including Q, but in the event France moved to all-digit codes before direct dialling from the UK was introduced. In these early days, the price for calling 0845 numbers from landlines was tied to BT's price for calls to local geographic numbers. Similarly, the price for calling 0870 numbers from landlines was tied to BT's price for national calls to geographic numbers. The use of names in allocating STD codes was intended to provide a mnemonic for the exchange in the same way as for the Director system, but the mnemonic link was often obscure. A single charge group code would usually cover multiple exchanges in various locations, which were identified either by a linked numbering scheme or extended codes. This meant that many exchanges were given alphanumeric STD codes that did not relate to their names: Swallow's code of 0GR 289 only made sense if you knew it was connected to Grimsby, for example. In addition, telephones connected to automatic exchanges in non-director areas had been issued with dials that had numbers but not letters printed on them, so would need to have new dials fitted to enable alphanumeric dialling. Director schemes were gradually introduced in other major cities of the UK — Birmingham, Edinburgh, Glasgow, Liverpool and Manchester.

Paul R. Gray and J. McCreary develop the analog-to-digital converter (ADC) MOS chip, used in digital telephony. [34]

The Second World War (1939-1945) saw the military use of radio-telephony links. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Early devices were bulky, consumed large amounts of power, and the network supported only a few simultaneous conversations. (Modern cellular networks allow automatic and pervasive use of mobile phones for voice- and data-communication.) Gilliland's Automatic circuit changer is put into service between Worcester and Leicester featuring the first operator dialing allowing one operator to run two exchanges. Meucci files a patent caveat (a statement of intention to file a patent application) [3] for a Sound Telegraph, but it does not describe an electromagnetic telephone.November 1889: A.G. Smith patents a telegraph switch which provides for trunks between groups of selectors allowing for the first time, fewer trunks than there are lines, and automatic selection of an idle trunk.

Mobile phone charger plugs prior to the universal standard (left to right) Samsung E900, Motorola V3, Nokia 6101 and Sony Ericsson K750. The Micro-USB interface is found on chargers for feature phones and smartphones. The USB-C interface is increasingly found on (chargers for) smartphones. [56] Usage of pre-existing 10- and 9-digit 0800 numbers and pre-existing 9-digit 0500 numbers continued as before. May 1876: Thomas Edison files first patent application for acoustic telegraphy for which U.S. patent 182,996 was granted 10 October 1876. Modern society has always seemed to have a bit of an obsession with technology. But no single device has had as much of an impact on the world than the mobile phone. Gonsalves, Antone (19 September 2005). "RealNetworks Launches Streaming Music on Sprint Phones". Information Week . Retrieved 16 October 2012.Francis Blake invents a carbon transmitter similar to Edison's that saves the Bell company from extinction. A unified code for Northern Ireland of (028) was introduced to replace eight area codes. The transition codes for Northern Ireland are shown below. In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs engineers, proposed hexagonal cells for mobile phones in vehicles. [20] At this stage, the technology to implement these ideas did not exist, nor had the frequencies been allocated. Two decades would pass before Richard H. Frenkiel, Joel S. Engel and Philip T. Porter of Bell Labs expanded the early proposals into a much more detailed system plan. It was Porter who first proposed that the cell towers use the now-familiar directional antennas to reduce interference and increase channel reuse (see picture at right) [21] Porter also invented the dial-then-send method used by all cell phones to reduce wasted channel time. June 2002: The Parliament of Canada responds by passing a motion unanimously 10 days later recognizing Alexander Graham Bell as the inventor of the telephone. [42] [43] a b c d e "1946: First Mobile Telephone Call". AT&T Labs. 2011. Archived from the original on 12 December 2012 . Retrieved 24 April 2012.