From Academic Kids

The Plessey Company plc was a British-based international electronics, defence and telecommunications company.



Founded in 1917 in Marylebone, central London but moving to Cottenham Road in Ilford early in 1919 (and then to Vicarage Lane where it remained) The Plessey Company became one of the largest manufacturers in this field as the radio and television industries grew.

Plessey were partners in the development of the Atlas Computer in 1962 and in the development of Digital telephone systems - System X - during the late 1970s.

GEC takeover bid

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, GEC and Plessey were the two largest suppliers to the MoD and in many competitions the only competitors. In January 1986 the bid was referred to the Monopolies and Mergers Commission (MMC), whose report published in August advises against the merger. The government concurred and blocked GEC's bid.

In 1988 Plessey and The General Electric Company (GEC) merged their telecom units to form GEC-Plessey Telecommunications (GPT), the UK's leading telecommunications manufacturer.

GEC Siemens takeover

In 1988 GEC and Siemens AG set up a jointly held company, GEC Siemens plc, to launch a hostile takeover of Plessey. GEC Siemens' initial offer was made of December 23 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 the Plessey defence businesses was not likely to meet with regulatory approval and in February GEC Siemens announced the proposed division of the company to take place as follows:

GEC acquisitions

  • UK
    • Plessey Avionics
    • Plessey Naval Systems
    • Plessey Cryptography
  • North America
    • Plessey Electronic Systems (75%)
    • Sippican
    • Leigh Instruments

Siemens acquisitions

  • UK
    • Plessey Defence Systems
    • Plessey Radar
    • Plessey Traffic Controls
    • Plessey's interest in GPT (reduced to 40%)
  • North America
    • Plessey Electronic Systems (25%)

Subsequent history

In 1997 British Aerospace acquired Siemens Plessey Systems. In 1999 Siemens acquired GEC's interests in Siemens Plessey. GEC acquired Siemens 40% interest in GPT the same year, renaming it Marconi Communications.

Plessey barcodes

Plessey is also a name for a barcode symbology developed by them, 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. Its chief advantages are the relative ease of printing using the dot-matrix printers 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 is not significant. The start element is a wide bar, and the stop element is two narrow bars. In between, the bars are in groups of four. High order bars appear leftmost. Narrow bars are zero and wide bars are 1.

This symbology is not self checking, though a modulo 10 or modulo 11 checksum (depending on application) is usually appended.

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