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72-409: PNNI is a suite of network protocols that can be used to discover an ATM network topology, create a database of topology information, and route calls over the discovered topology. PNNI is a link-state routing protocol , which means that the protocol collects information about the current state of links and nodes in the network to build a network database. The PNNI network database can be used to determine

144-541: A new extension to the London Underground Central line from Leytonstone to Newbury Park , into a factory. The company also built a new factory at Swindon in Wiltshire, and opened several other shadow factories around the country to produce munitions. Caswell , Northamptonshire became the site of Plessey's first dedicated research centre in 1940. The wartime workforce of Plessey grew to over 10,000. With

216-431: A change in the connectivity map happens, it is necessary to recompute the shortest-path tree and then recreate the routing table. BBN Technologies discovered how to compute only that part of the tree which could have been affected by a given change in the map. In some cases, it is reasonable to reduce the number of nodes that generate LSA messages. For this reason, a topology reduction strategy can be applied, in which only

288-563: A comprehensive suite of photonic characterisation and applications laboratories. Their original microLED product was an illuminator for display light engines (DMD and LCOS), which offered a 40% reduction in light engine size whilst delivering higher energy efficiency. They have now upgraded to full-field emissive microLED displays that combine very high-density RGB pixel arrays with high-performance CMOS backplanes to produce very high-brightness, low-power and high-frame-rate image sources. These are innovative products that are widely recognised within

360-507: A joint holding company , GEC Siemens, to launch a hostile takeover of Plessey. Their initial offer was made on 23 December 1988, valuing Plessey at £1.7 billion. Again, Plessey rejected the offer and again it was referred to the MMC. The original proposal envisaged joint ownership of all of Plessey's defence businesses, with GPT and Plessey's North American businesses split in the ratios 60:40 and 51:49 respectively. The level of GEC's involvement in

432-421: A legal entity) and merged GPT with the telecoms units of its other subsidiaries, namely Marconi SpA, GEC Hong Kong and ATC South Africa, to form Marconi Communications . In December 1999, GEC's defence arm Marconi Electronic Systems was amalgamated with British Aerospace to form BAE Systems. The remainder of GEC was renamed to Marconi plc, and Marconi Communications became its principal subsidiary. This company

504-418: A link-state protocol, the only information passed between nodes is connectivity related . Link-state algorithms are sometimes characterized informally as each router "telling the world about its neighbors." In link-state routing protocols, each router possesses information about the complete network topology. Each router then independently calculates the best next hop from it for every possible destination in

576-533: A major subsidiary was set up, Plessey Electronic Systems, which incorporated the three businesses and by 1986 achieved sales of over £500 million and employed 15,000. Plessey were partners in the development of the Atlas Computer in 1962 and in the development of digital telephone systems, including System X , from the late 1970s. In 1988, Plessey's Telecommunications Division merged with that of GEC to become GEC Plessey Telecommunications . Plessey Naval Systems

648-741: A mechanism that would calculate routes more quickly when network conditions changed and thus lead to more stable routing. The technique was later adapted for use in the contemporary link-state routing protocols IS-IS and OSPF. Cisco literature refers to Enhanced Interior Gateway Routing Protocol (EIGRP) as a "hybrid" protocol, despite the fact it distributes routing tables instead of topology maps. However, it does synchronize routing tables at start-up as OSPF does and sends specific updates only when topology changes occur. In 2004, Radia Perlman proposed using link-state routing for layer 2 frame forwarding with devices called routing bridges , or Rbridges. The Internet Engineering Task Force has standardized

720-429: A multi-cloud environment. Variable access nodes across the interface protocol may also bypass the simultaneous access node problem. The Optimized Link State Routing Protocol (OLSR) is a link-state routing protocol optimized for mobile ad hoc networks (which can also be used on other wireless ad hoc networks ). OLSR is proactive and uses hello and topology control messages to disseminate link-state information into

792-555: A number of downsizes, including the purchase of the power semiconductor and silicon on sapphire operation at Lincoln, Lincolnshire by Dynex Semiconductor in 2000, the company renamed itself Zarlink Semiconductor in 2001. The GPS fabrication plant in Plymouth was acquired by Xfab . After the sale of the Roborough site in Plymouth to Xfab , the original Plessey Semiconductors site at Cheney Manor, Swindon continued to operate under

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864-435: A public company on 17 March 1937. Aircraft components was another market into which the company diversified. In 1936, Plessey obtained a number of important manufacturing licences from American companies such as Breeze Corporation for aircraft multi-pin electrical connectors , Federal Laboratories for Coffman starters (an explosive cartridge device used to start aircraft engines), and Pump Engineering Services Corporation for

936-600: A series of computer systems and peripherals compatible with Digital Equipment Corporation 's PDP-11 . By 1972, Plessey designed the first industrial capability-based security computer, a fault-tolerant multiprocessor system called Plessey System 250 . Plessey was also the lead contractor for the Ptarmigan communications system supplied to the British Army , which adopted the System 250 architecture. Plessey Controls, from 1982 to

1008-401: A short message, the link-state advertisement , which: This message is sent to all the nodes on a network. As a necessary precursor, each node in the network remembers, for every one of its neighbors, the sequence number of the last link-state message which it received from that node. When a link-state advertisement is received at a node, the node looks up the sequence number it has stored for

1080-450: A strong focus on telecommunications and defence products, particularly with a major expansion into large projects, rolling out the microwave backbone of MTN, one of South Africa's first GSM cellular networks and the installation of a fibre optic network and radio broadcasting system in Malaysia. A software division was formed through the acquisition of BSW data, largely staffed by engineers from

1152-563: A subset of the network nodes generate LSA messages. Two widely studied approaches for topology reduction are multipoint relays that are at the base of the Optimized Link State Routing Protocol (OLSR) but have also been proposed for OSPF and connected dominating sets that were again proposed for OSPF. With Fisheye State Routing (FSR), the LSA are sent with different time-to-live values to restrict their diffusion and limit

1224-482: A successor company of GEC. The Plessey company was founded in 1917 in Marylebone , central London. The original shareholders were Thomas Hurst Hodgson, C. H. Whitaker, Raymond Parker and his brother Plessey Parker. A talented German engineer, William Oscar Heyne, was employed by the company. Heyne later became the managing director and chairman of Plessey and was one of the key figures in the development of Plessey during

1296-483: A task that had previously required switching out multiple crystals. South African insurance and investment company Sanlam bought 26% of Plessey South Africa in 1974, with first right of refusal to purchase more of the company. These shares were later transferred to Sankorp, Sanlam's industrial holdings company. In 1989, when GEC-Siemens took control of the Plessey Company, Sankorp indicated its intention to purchase

1368-540: A wholly owned subsidiary of Sankorp under the new name of Plessey Tellumat South Africa Limited (PTSA). The addition of the name Tellumat had a double symbolism, firstly for the company's commitment to exports, as it is the name of its UK-based export subsidiary. Secondly, the name derives from the Tellurometer, South Africa's world first electronic surveying development—and by implication, a commitment to ongoing electronic research and development. PTSA continued to grow with

1440-446: Is passed between nodes using PNNI topology state packets (PTSPs). These packets utilize the routing control channel (RCC; VPI = 0 and VCI = 18) between adjacent nodes. The RCC is also used for Hello packets and other PNNI messages. If the switch is unable to establish the RCC with the adjacent node, then PTSE information is not exchanged. Once a node receives PTSE information, the node stores

1512-625: The Internet , these are called routers ). The basic concept of link-state routing is that every node constructs a map of the connectivity to the network in the form of a graph , showing which nodes are connected to which other nodes. Each node then independently calculates the next best logical path from it to every possible destination in the network. Each collection of best paths will then form each node's routing table . This contrasts with distance-vector routing protocols, which work by having each node share its routing table with its neighbors, in

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1584-608: The Plessey Corporation in the same year. Trading started off at R4.80 a share. On the evening of 6 February 1996, a devastating fire swept through two bays of the White Road factory in Retreat, Cape Town causing huge damage to stock, instruments, plant and work in progress. No one was injured, but work was disrupted for several weeks. Large sections of the factory had to be rebuilt. At the end of 1996, Plessey Corporation sold off

1656-529: The Transparent Interconnection of Lots of Links (TRILL) protocol to accomplish this. More recently, this hierarchical technique was applied to wireless mesh networks using the Optimized Link State Routing Protocol (OLSR). Where a connection can have varying quality, the quality of a connection can be used to select better connections. This is used in some ad hoc routing protocols that use radio frequency transmission. The first main stage in

1728-476: The 1920s and 1930s. The company moved to Cottenham Road in Ilford early in 1919. In 1925, the original company was wound up and a new one was formed with a greater share capital. Most of the early work carried out by the company was in mechanical engineering. An early customer of Plessey was a galvanising company called British Electro Chemists. One of that company's shareholders was Byron G. Clark, an American, who

1800-504: The 1950s and 1960s. The secure status of the factory attracted many other secret contracts and led to it becoming one of the major designers and manufacturers of cryptographic equipment. Exchange Works is now luxury flats. The South African roots of Plessey can be traced to the acquisition of AT&E and Ericsson in 1963, and a Cape Town based company, the Instrument Manufacturing Company (IMC), acquired in 1964. At

1872-452: The 1960s the Group continued to expand, setting up facilities at places such as West Leigh ( Havant , Hampshire) and Templecombe , Somerset. In 1961 Plessey merged with Ericsson Telephones and Automatic Telephone Manufacturing Company of Liverpool, to become Britain's largest manufacturer of telecommunications equipment, including the majority of the country's crossbar switches . Alongside

1944-532: The 8" Plymouth facility during 2010, exploiting the combined technology base in the development of new processes and products in a number of markets. The Swindon site on the Cheney Manor Industrial estate in the west of the town was demolished in July 2012. In 2011/2, Plessey acquired the rights to disruptive GaN-on-silicon technology by acquisition of CamGaN, a startup company, from Cambridge Enterprises. Using

2016-478: The GaN-on-silicon technology and semiconductor expertise, Plessey Semiconductors Ltd manufactured solid state lighting, horticultural lighting and medical sensing products. Their GaN-on-silicon i2LED high power LEDs and Stellar Orion Beam Forming modules, launched in autumn 2016, which enabled new form factors of lighting products and remove critical design constraints for lighting product designers. In horticulture,

2088-600: The Plessey Attis Growlight was at the forefront of an engineering approach to LED based plant grow lights which was then developed into a new brand, Hyperion Grow Lights. The company's medical products were based on the EPIC sensor, which were used in the advanced portable ECG monitoring device, Impulse, and was also the basis of an R&D program, named Warden, to develop driver alertness monitoring devices in automotive and aeronautical applications. In 2017, Plessey pivoted

2160-613: The Plessey businesses: In 1997, British Aerospace and DaimlerChrysler Aerospace acquired the UK operations and the German part of Siemens Plessey Systems, respectively. By 1997, the GPT name disappeared in the UK and the company was known as Siemens GEC Communication Systems (SGCS), which later became Siemens Communications . In August 1998, GEC acquired Siemens' 40% stake in GPT (by now only existing as

2232-609: The Plessey defence businesses was not likely to meet with regulatory approval and in February 1989, GEC Siemens announced a new organisation. In an effort to head off the bid, Plessey announced in May 1989 the closure of its compound semiconductor business in Towcester , Plessey 3-5. The takeover was completed in September 1989. In April 1990, GEC and Siemens agreed a new structure of ownership of

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2304-526: The Sales and marketing business of Telefunken, Pioneer and Satellite TV. In August 1998, Plessey Corporation was bought by Dimension Data Holdings and Worldwide African Investment Holdings for R1.6 billion. The new owners retained BSW Data, Plessey Solutions and Communications Systems. The remaining divisions, notably with a product development and manufacturing focus, were bought back by a combined management buyout supported by Rand Merchant Bank. The corporate name

2376-602: The Telecommunications Division, three other businesses were set up: Plessey Avionics and Communications, Plessey Radar and Plessey Marine. In 1967 or 1968, English Electric was subject to a takeover bid by Plessey, but chose instead to accept an offer from GEC . In 1970, the Command and Control unit was set up at Christchurch, Dorset , which became the centre of the Plessey Defence Systems business. In 1979,

2448-624: The Zarlink Semiconductor name until it was sold to MHS Industries in early 2008. In February 2009, the UK business was forced into receivership following the collapse of the parent MHS Electronics business in France. After a subsequent management buyout the company traded as Plus-Semi Ltd. The Roborough site ( 8" and 6" lines) was re-acquired from Xfab on 1 January 2010 and the company renamed as Plessey Semiconductors Ltd. The new company transferred its bipolar processes on silicon and SOI into

2520-554: The assets of the Plessey group. The majority of Plessey's defence assets were amalgamated into BAE Systems in 1999 when British Aerospace merged with the defence arm of GEC, Marconi Electronic Systems (MES). The Plessey Microsystems division was the subject of a management buyout in 1988 becoming Radstone Technology , which survives today as part of Abaco Systems based in Towcester , Northamptonshire . The bulk of Plessey's telecommunications assets were acquired by Ericsson through its 2005 acquisition of Marconi Communications ,

2592-405: The candidate list. (When there are none, all the nodes in the network will have been added to the tree.) This procedure ends with the tree containing all the nodes in the network. For any given destination node, the best path for that destination is the node which is the first step from the root node, down the branch in the shortest-path tree which leads toward the desired destination node. Whenever

2664-507: The company. During the 1920s Plessey began to diversify into electrical manufacturing. Important contracts included the manufacture of early radios for Marconi and the production of telephones for the General Post Office . In order to increase production, Plessey moved to Vicarage Lane, Ilford , in 1923. In 1929, the television pioneer John Logie Baird had his first production televisions made by Plessey. The company also produced

2736-585: The contents, or element information, in the database. This information is used to generate precomputed routing tables that identify routes to other network devices. PNNI uses the Dijkstra's algorithm for shortest path first (SPF) calculation. The PNNI database is also used to perform on-demand routing when the appropriate routing table does not contain a viable path. PNNI measures line capacities and delays in addition to simple cost metrics. Link-state routing protocol Link-state routing protocols are one of

2808-423: The early layers within the process to emit native green, opening more opportunities for markets such as military. Plessey also achieved the world's first GaN-on-silicon monolithic, wafer to wafer bonding, in May which was a massive breakthrough for not only the company but the industry. In South Africa, following the successful GEC/Siemens takeover, after protracted negotiations in 1991, Plessey South Africa became

2880-533: The end of the war the company's orders dropped from £5 million in 1944/5 to £263,000 in 1946 and the workforce fell to less than 6,000. Radio and television sales were the main area of activity until the renewed demand for defence products with the onset of the Korean War . From a turnover of £5 million in 1949/50, there was an increase to £32 million in 1959/60. In 1951, the Electronics Division

2952-401: The first British-made portable radio in the same year. The manufacture of electrical components became an area of growth for Plessey. A vast array of components was manufactured, many under licence from overseas companies. Plessey became one of the largest manufacturers in this field as the radio and television industries grew. In 1936/7, turnover was more than £1 million and Plessey became

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3024-411: The first adaptive routing network of computers, using link-state routing, was designed and implemented during 1976–1977 by a team from Plessey Radar led by Bernard J Harris; the project was for "Wavell" – a system of computer command and control for the British Army . The first link-state routing concept was published in 1979 by John M. McQuillan (then at Bolt, Beranek and Newman ) as

3096-585: The focus of the business to the R&;D and manufacturing of microLEDs (micro light-emitting diodes) as a market disrupting display technology for a wide range of applications, including: Augmented Reality, Mixed Reality, smartphones, televisions, smartwatches, head-up displays, head-mounted displays and more. Plessey continues to operate in the Roborough site with leading-edge 150mm and 200mm wafer processing facilities to undertake design, test and assembly of products, and

3168-615: The following types of network components: To enable communications with other nodes, each switch needs to have all the PTSE information for each switch in the network. Each node is responsible for flooding out its own PTSE information to all the other switches in the network. Since up-to-date PTSE information is required for optimal routing decisions to be made, there are several different mechanisms in place to help ensure that all nodes have reasonably accurate PTSE information. The five common reasons for updating PTSEs are as follows: PTSE information

3240-405: The industry with many accolades from prestigious electronics, engineering and display industry award programs, including: Elektra Awards 2017, British Engineering Excellence Awards 2017, National Technology Awards 2018, CES Innovation Awards 2019 and Electronics Industry Awards 2019. In March 2019, Plessey used their GaN-on-silicon technology, which natively emits blue, to innovatively engineer

3312-414: The link-state algorithm is to give a map of the network to every node. This is done with several subsidiary steps. First, each node needs to determine what other ports it is connected to over fully working links; it does this using reachability protocol that it runs periodically and separately with each of its directly connected neighbours. Each node periodically (and in case of connectivity changes) sends

3384-642: The manufacture of Pesco fuel pumps . Plessey went on to produce large numbers of these fuel pumps for Rolls-Royce Merlin engines, and in 1940 the fuel pump for Britain's first jet engine was also supplied by Plessey. During World War II , Plessey produced a vast array of components and equipment for the war effort, including shell cases, aircraft parts, and radio equipment such as the R1155 (receiver), and T1154 (transmitter). In all, 161,500 pieces of wartime electronic equipment were produced. To allow greater production, Plessey converted five miles of twin tunnel, built for

3456-667: The mid-1980s, also manufactured a type of geiger counter known as the Portable Dose Rate Meter (PDRM). It gave highly accurate readings, using the Gray system of measurement and used standard torch batteries. They were built for civil defence, but also used by the British Army. Most ended up in the hands of the Royal Observer Corps and manufacture would discontinue by the late 1980s. In 1959 AT&E, later Plessey, became

3528-409: The mobile ad hoc network. Using hello messages, each node discovers two-hop neighbor information and elects a set of multipoint relays (MPRs). MPRs make OLSR distinct from other link-state routing protocols. Individual nodes use the topology information to compute next-hop paths regarding all nodes in the network using shortest-hop forwarding paths. Plessey Radar The Plessey Company plc

3600-405: The neighbors is recomputed and then flooded throughout the network whenever there is a change in the connectivity between the node and its neighbors, e.g., when a link fails. The second main stage in the link-state algorithm is to produce routing tables by inspecting the maps. Each node independently runs an algorithm over the map to determine the shortest path from itself to every other node in

3672-566: The network structure and the current state of network components. To build the PNNI network database, each PNNI node must receive topology information from all the other devices in the network. To keep the database current, the node must receive regular updates from other nodes. The PNNI protocol communicates the state of a PNNI network in PNNI Topology State Elements (PTSEs). PTSEs are discrete messages that contain information about one of

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3744-402: The network using local information of the topology. The collection of best next hops forms the routing table. This contrasts with distance-vector routing protocols , which work by having each node share its routing table with its neighbours. In a link-state protocol, the only information passed between the nodes is the information used to construct the connectivity maps. What is believed to be

3816-419: The network; generally, some variant of Dijkstra's algorithm is used. A node maintains two data structures: a tree containing nodes which are "done", and a list of candidates . The algorithm starts with both structures empty; it then adds to the first one the node itself. The variant of a greedy algorithm then repetitively does the following: The two steps are repeated as long as there are any nodes left in

3888-523: The only competitors. In January 1986, the bid was referred to the Monopolies & Mergers Commission (MMC), whose report published in August advised against the merger. The government concurred and blocked GEC's bid. In 1988, Plessey and GEC merged their telecom units to form GEC Plessey Telecommunications (GPT), at the time the UK's leading telecommunications manufacturer. In 1988, GEC and Siemens set up

3960-505: The overhead due to control messages. The same concept is used also in the Hazy Sighted Link State Routing Protocol . If all the nodes are not working from exactly the same map, routing loops can form. These are situations in which, in the simplest form, two neighboring nodes each think the other is the best path to a given destination. Any packet headed to that destination arriving at either node will loop between

4032-515: The prime contractor for a new UK air defence system, known by the company under the name Plan Ahead and, from 1961, as Project Linesman . To enable the system to be designed and built without too much information becoming public knowledge, a new factory called "Exchange Works" was built in Cheapside in Liverpool city centre, where young employees were granted exemption from conscription. At the heart of

4104-532: The recently terminated South African space programme in which PTSA had also participated, both in the electronics of the launch vehicle and the satellite itself. 1995 was a landmark year in the history of the business in South Africa. The merger of PTSA and Tek Electronics, the consumer electronics audio and video products, manufacturer and distributor, (also wholly owned by Sankorp) took the business full circle back to its consumer electronics roots. This resulted in

4176-625: The remaining 74% of shares in the South African subsidiary. Plessey had a manufacturing plant in Sydney, Australia that made defense equipment and TVs. In December 1985, GEC launched a takeover bid for the Plessey Company, valuing the group at £1.2 billion. Both Plessey and the Ministry of Defence were against the merger, since GEC and Plessey were the two largest suppliers to the MoD and in many tenders

4248-591: The renaming of PTSA back to the original name of Plessey South Africa Limited. The full acquisition of AWA-Plessey Communications, which Plessey jointly owned in Australia with Amalgamated Wireless (Australasia) Ltd (AWA) and had a similar product portfolio, resulted in penetration into the Pacific Rim market. The culmination of this growth was the company's listing on the Johannesburg Stock Exchange (JSE) as

4320-448: The source of that link-state message; if this message is newer (i.e., has a higher sequence number), it is saved, the sequence number is updated, and a copy is sent in turn to each of that node's neighbors. This procedure rapidly gets a copy of the latest version of each node's link-state advertisement to every node in the network. The complete set produces the graph for the map of the network. The link-state message giving information about

4392-509: The system, installed in a huge building in the middle of a council housing estate in West Drayton , was the computer room, occupying an area of around 300 by 150 feet (91 m × 46 m) and filled with around 1,000 7-foot-high (2.1 m) racks of electronics, including mainly the XL4 computer, based entirely on germanium transistors and using a computer language developed at Exchange Works in

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4464-703: The time, IMC was in the process of industrialising a unique South African invention, the Tellurometer , the first successful microwave electronic distance measurement equipment. The instrument was invented by Dr. Trevor Lloyd Wadley of the Telecommunications Research Laboratory of the South African Council for Scientific and Industrial Research (CSIR), also responsible for the Wadley loop receiver, which allowed precision tuning over wide bands,

4536-442: The two main classes of routing protocols used in packet switching networks for computer communications , the others being distance-vector routing protocols . Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS). The link-state protocol is performed by every switching node in the network (i.e., nodes which are prepared to forward packets; in

4608-403: The two, hence the name. Routing loops involving more than two nodes are also possible. This can occur since each node computes its shortest-path tree and its routing table without interacting in any way with any other nodes. If two nodes start with different maps, it is possible to have scenarios in which routing loops are created. In certain circumstances, differential loops may be enabled within

4680-426: The world using in-house software. Each of their 140 management reporting entities used HP125s with DIVAT (data input, validation and transmission) software. Nearly 450 validation rules ensured accuracy within and between various reports. The data were then transmitted to Ilford where a HP 3000 ran Fortran software for consolidation and reporting—also on HP125s. During the 1970s and early 1980s, Plessey manufactured

4752-510: Was a British electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after World War II by acquisition of companies and formed overseas companies. It was listed on the London Stock Exchange and was a constituent of the FTSE 100 Index . In 1989, it was taken over by a consortium formed by GEC and Siemens which split

4824-451: Was affected by the dot-com bubble and was restructured into Marconi Corporation in 2003, then collapsed in 2005. Most of it (including Marconi Communications) was bought by Ericsson and the remainder became Telent . The part of GPT which evolved into Siemens Communications would eventually become Siemens Enterprise Communications in 2008. GEC Plessey Semiconductors (GPS) was purchased by Mitel Semiconductors of Canada in 1998. After

4896-427: Was also a business associate of T. H. Hodgson, one of the founders of Plessey. The Clark family would eventually dominate the management of Plessey for most of its history. Byron's son Allen George Clark joined the company in 1921, and went on to become a driving force behind the development of Plessey, followed later by his sons John Allen Clark , and Michael William Clark, both of whom rose to prominent positions in

4968-441: Was changed to Tellumat Pty Ltd. Tellumat continues to develop and manufacture Plessey-branded products as before and operates in the defence , telecommunications and contract manufacturing markets. The name is also used to refer to a barcode symbology developed by Plessey, which is still used in some libraries and for shelf tags in retail stores, in part as a solution to their internal requirement for stock control. The system

5040-426: Was first used in the early 1970s by J.Sainsbury to identify all of its products on supermarket shelves for its product restocking system. The chief advantages are the relative ease of printing using the dot-matrix printers, which were popular at the time of the code's introduction, and its somewhat higher density than the more common 2 of 5 and 3 of 9 codes. Plessey barcodes use two bar widths. Whitespace between bars

5112-523: Was formed in 1986 by the merger of Plessey Marine with Plessey Displays, which had been part of Plessey Radar. Plessey were among the first firms to use computers. Their Training Department developed an interactive management game (PITDEX) using TeleType printer/keyboards to link to LEASCO computers in the United States via standard telephones and acoustic couplers . Plessey also pioneered the gathering and consolidation of accounting information from around

5184-522: Was started by Michael Clark. By 1955, this had expanded to become the Electronics and Equipment Group with 5,000 staff. The following year the Roke Manor research facility was set up under the direction of H. J. Finden near Romsey , Hampshire. Plessey produced an early integrated circuit model in 1957, before the patents of Jack St. Clair Kilby of Texas Instruments and Robert Noyce of Fairchild. In

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