The Telephone Network

It fascinates me how someone can have a brilliant idea and others just cannot imagine it ever being of any use. I think this is a fine example. In 1875, a certain Mr A.G. Bell formed the American Bell Telephone Company. A year later, he patented the first improvement in telegraphy, thus creating the first wired voice transmission where a pair of physical wires were connected between two devices. In 1876, Bell had a meeting with Western Union and according to the minutes of that meeting, Bell offered all rights to the telephone for sale to them for a mere $100,000. Bell’s profession was actually that of a voice teacher, yet he claimed to have discovered an instrument of great practical value in communication which had been overlooked by thousands of workers who had spent years in the field. He believed that a telephone would one day be installed in every residence and place of business, but at that meeting the committee thought Bell’s proposals were too fantastic. They felt that the central exchange alone would represent a huge outlay in land and buildings, to say nothing of the relevant equipment. In conclusion, the committee felt that it had no option but to advise against any investments in Bell’s scheme. They did not doubt that it would find uses in special circumstances, but any development of the kind and of the scale which Bell so fondly imagined was utterly and completely out of the question!

Alexander Graham Bell (March 3, 1847– August 2, 1922) was a Scottish-born inventor, scientist, and engineer who is credited with inventing and patenting the first practical telephone. His father, grandfather, and brother had all been associated with work on elocution and speech, also both his mother and wife were deaf, so profoundly influencing Bell’s life’s work. His research on hearing and speech further led him to experiment with hearing devices which in time culminated in Bell being awarded the first U.S. patent for the telephone on March 7, 1876. Bell considered his invention an intrusion on his real work as a scientist and refused to have a telephone in his study. But in 1878, some two years after he had invented the telephone, Bell is quoted as saying ”It is conceivable that cables of telephone wires could be laid underground, or suspended overhead, communicating by branch wires with private dwellings, country houses, shops, manufactories etc., etc., uniting them through the main cable with a central office where wires could be connected as desired, establishing direct communication between any two places in the city. Such a plan as this, though impracticable at the present moment will, I firmly believe, be the outcome of the introduction of the telephone to the public. Not only so, but I believe, in the future, wires will unite the head offices of the Telephone Company in different cities, and a man in one part of the country may communicate by word of mouth with another in a distant place. I am aware that such ideas may appear to you Utopian. Believing however as I do that such a scheme will be the ultimate result of the telephone to the public, I will impress upon you all the advisability of keeping this end in view, that all present arrangements of the telephone may be eventually realised in this grand system.” Many other inventions marked Bell’s later life, including some groundbreaking work in optical telecommunications, hydrofoils as well as aeronautics. Although Bell was not one of the 33 founders of the National Geographic Society, he had a strong influence on the magazine whilst he served as its second president from January 7, 1898, until 1903.

The commercialisation of the telephone began in 1876, with instruments operated in pairs for private use between two locations. It became more and more commonplace for users to want a fixed telephone in their home, but to begin with those users who wanted to communicate with persons at multiple locations had as many telephones as necessary for the purpose. To alert another user to the establishing of a telephone call was done by first whistling loudly into the transmitter until the other party heard the alert. Bells were soon added to stations for signalling so that an attendant no longer needed to wait for the whistle. Later on, telephones took advantage of the exchange principle which was already employed in telegraph networks. Each telephone was connected by wire to a telephone exchange established for a town or area. Communications outside this exchange area used a system called trunking and this was installed between exchanges. The Public Switched Telephone Network, or PSTN as it is often referred to, began. Alexander Bell demonstrated the telephone to Queen Victoria on 14 January 1878 at Osborne House on the Isle of Wight with calls to London, Cowes and Southampton and these were the first long-distance calls in the UK. The Telephone Company Ltd (Bell’s Patents) was registered on 14 June 1878 to market Bell’s patent telephones in Great Britain and it concentrated its efforts on the sale of telephone instruments and the fitting of private lines. The National Telephone Company (NTC) was then formed on 10 March 1881 and this brought many smaller local companies together. Meanwhile in the U.S.A. Bell co-founded the American Telephone and Telegraph Company (AT&T) in 1885, but here in the U.K. the NTC had already formed the basis of our early telephone network which existed until the Telephone Transfer Act 1911. Then, because the National Telephone Company had become a monopoly, the Liberal government decided to take it into public hands so it was taken over by the General Post Office (GPO) in 1912 and up until 1982 the main civil telecommunications system in the UK was a monopoly, even when the Post Office Act 1969 changed the General Post Office from a department of state to a public corporation, known as the Post Office, with the telephony side becoming Post Office Telecommunications. There was still one area in the UK which had its own telecommunications provider and this was Hull, served by KCom, though it was known then as Kingston Communications. Meanwhile broadcasting of radio and television was a duopoly of the British Broadcasting Corporation (BBC) and the Independent Broadcasting Authority (IBA) where these two organisations controlled all broadcast services. They also directly owned and operated the broadcast transmitter sites. Mobile phone and Internet services did not exist at all at that time. The civil telecommunications monopoly ended when Mercury Communications arrived in 1983 and the Post Office system then evolved into British Telecom which was privatised in 1984. All the broadcast transmitters which belonged to the BBC and IBA were privatised during the 1990s and then belonged to Babcock International and Arqiva. British Rail Telecommunications was created by British Rail (BR) in 1992 and operated its own national trunked radio network providing dedicated train-to-shore mobile communications, and in the early 1980s BR helped establish the Mercury Communications, now Cable & Wireless Co (C&WC), core infrastructure by laying a resilient ‘figure-of-eight’ fibre optic network alongside Britain’s railway lines, spanning London, Bristol, Birmingham, Leeds and Manchester.

For many years users of telephone lines were commonly referred to as subscribers because they rented access to their local provider’s network via a fixed telephone line, a pair of wires connecting a handset both provided and maintained by the network provider into the public switched telephone network (PSTN) which had a dedicated port in the telephone exchange equipment, thus supplying the subscribers unique telephone number and a meter for the charging of calls. When there was a shortage of cabling in a particular area two subscribers would share a single pair of wires with simple switching system enabling one subscriber or the other to use the network at any one time. These were naturally referred to as shared service lines. In the early days of the service automation was introduced between the telephone and the exchange so that each subscriber could directly dial another subscriber connected to the same exchange, however calls to a subscriber in a different exchange area required manual switching by operators who were housed in switch rooms of large exchanges around the country. Later, more sophisticated address signalling enabled the direct dialling of calls by subscribers of the service and the use of operators was reduced to handling calls to the emergency services, these being to the fire, police, ambulance and coastguard. Networks were gradually designed and extended in a hierarchical manner until they spanned cities, countries, continents and oceans. Also, the shared service system had to be phased out in the UK some years later when other telephone companies were allowed to connect their services to the BT network, thus requiring a common standard of connection for all to use.

The PSTN network now provides infrastructure and services for public telecommunication and is the aggregate of the world’s circuit-switched telephone networks that are operated by national, regional, or local telephony operators. These consist of wires, fibre-optic cables, microwave transmission links, cellular networks, communications satellites and undersea telephone cables, all of which are interconnected by switching centres which allow for most telephones to communicate with each other. Originally a network of fixed-line analogue telephone systems, the PSTN is now almost entirely digital in its core network. It includes mobile and other networks, as well as fixed telephones. In the 1970s, the telecommunications industry began to implement a different service for transmitting data over much of the end-to-end equipment that was already in use in the PSTN. In the 1980s, the industry began planning for digital services assuming they would follow much the same pattern as voice services, and conceived end-to-end circuit-switched services, known as the Broadband Integrated Services Digital Network (B-ISDN) but this was overtaken by the Internet. At the turn of the 21st century, the oldest parts of the telephone network may still use analogue technology for the last mile or less to the end user, but digital technologies such as Digital subscriber line (DSL), Integrated Services Digital Network (ISDN) and optical fibre connectivity have become more common in this portion of the network. There are also many private networks, usually used by large companies and which are linked to the PSTN through limited ‘gateways’ such as a private branch exchange (PBX). This is like a small telephone exchange or switching system that serves a private organisation and permits sharing of central office trunks between internally installed telephones, and provides intercommunication between those internal telephones within the organisation without the use of their external lines. The central office lines provide connections to the PSTN network and the concentration aspect of a PBX permits the shared use of these lines between all stations in the organisation. The PBX enables two or more extensions to directly connect whilst not using the PSTN network. This method reduces the number of lines needed from the organisation to the public switched telephone network and saves on call charges. Besides telephones, other devices such as a fax machines or computer modems can be connected to the PBX and each may have its own, dedicated extension number that is usually mapped to the numbering scheme of the central office and the telephone number block allocated to the PBX. Also a large organisation may connect directly to its other offices by means of private circuits which are permanently connected, which if used enough allow the transmission of voice and data for a lower cost than normal calls. At one time these were done over analogue lines, then digital ones, but these are largely being overtaken by other services now including mobile phone and Internet services.

So far as the regulation of the communication industry is concerned, the Consultative Committee for International Telephony and Telegraphy (CCITT) was created in 1956 but was renamed in 1993 as the International Telecommunication Union – Telecommunication (ITU-T). It is one of the three sectors of the International Telecommunication Union (ITU), the other two sectors being Radio (ITU-R) and Development (ITU-D). The technical operation of the PSTN adheres to the standards created by the ITU-T which coordinates standards for telecommunications and information communication technology for such things as cybersecurity, machine learning, and video compression between its member states, private sector members, and academia members. These standards allow different networks in different countries to interconnect seamlessly. Technically it is the E.163 and E.164 standards which provide a single global address space for telephone numbers. The combination of the interconnected networks and the single numbering plan thus allow telephones around the world to dial each other. Here in the UK the regulation of communications has changed many times during the same period and most of the bodies have been merged into Ofcom, this being the independent regulator and competition authority for the UK industry. So to my mind, it shows that Alexander Bell’s idea of communications was an excellent starting point, but it has surely now developed way beyond his visions or expectations.

I am reminded…
I used to work for British Telecom and for a few years I worked as part of their Midland Region Mobile Exhibition Team. This involved the staffing of various exhibitions, mainly around the Midlands and on one occasion I was at a public agricultural show where the stand was in an open aircraft hangar. It was a bitterly cold day, but we were in our official uniforms of light grey trousers, thin white shirt, blue jacket with brass buttons and we were all freezing cold. So I found a nearby stall holder selling very thick navy blue jumpers that perfectly matched our uniforms and we bought those for ourselves. Our BT Exhibition Manager turned up and was not too happy, but he knew we needed them so the extra clothing was approved!

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