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On the left, the NEC TK 80 kit, based on Intel 8080 chip, on the centre, Busicom calculator motherboard, based on Intel 4004 chip, and on the right, the Busicom calculator, fully assembled in Ueno, Tokyo
On the left, the NEC TK 80 kit, based on Intel 8080 chip, on the centre, Busicom calculator motherboard, based on Intel 4004 chip, and on the right, the Busicom calculator, fully assembled in Ueno, Tokyo

Busicom was a Japanese company that owned the rights to the first microprocessor, the Intel 4004, which they created in partnership with Intel in 1970.

Busicom asked Intel to design a set of integrated circuits for a new line of programmable electronic calculators in 1969.[1][2] In doing this, they spurred the invention of the first microprocessor to be commercialized,[3] the Intel 4004. Busicom owned the exclusive rights to the design and its components in 1970 but shared them with Intel in 1971.[4]

Two companies have done business as "Busicom" over the years; the Nippon Calculating Machine Corp, Ltd and Broughtons & Co.(Bristol) Ltd of the UK.


Nippon Calculating Machine Corporation, Ltd

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The Nippon Calculating Machine Corp was incorporated in 1945 and changed its name in 1967 to Business Computer Corporation, Busicom. Due to a recession in Japan in 1974, Busicom became the first major Japanese company in the calculator industry to fail. Originally, they made Odhner type mechanical calculators and then moved on to electronic calculators always using state of the art designs. They made the first calculator with a microprocessor for their top of the line machines[5] and they were the first to make calculators with an all-in-one calculator chip, the Mostek MK6010, for their line of inexpensive machines.

One of their last mechanical calculators is the HL-21, an Odhner type machine.[6]

Their first calculator with a microprocessor is the Busicom 141-PF.

Their entry based calculators, the Busicom LE-120A (Handy-LE) and LE-120S (Handy),[7] were the first to fit in a pocket and also the first calculators to use an LED display.

The Microprocessor's History as seen from Busicom's Side

In order to limit production cost, Busicom wanted to design a calculator engine that would be based on a few integrated circuits (ICs), containing some ROMs and shift registers and that could be adapted to a broad range of calculators by just changing the ROM IC chips. Busicom's engineers came up with a design that required 12 ICs[8] and asked Intel, a company founded one year earlier in 1968 for the purpose of making solid state random-access memory (RAM), to finalize and manufacture their calculator engine.

Ted Hoff was assigned to the project and after studying the design came up with a much more elegant, 4 ICs implementation centered on what was to become the 4004 microprocessor surrounded by a mixture of 3 different ICs containing ROM, shift registers, input/output ports and some RAM Intel's first product (1969) was the 3101 Schottky TTL bipolar 64-bit SRAM.[9]

Busicom's management agreed to Hoff's new design[10] and the chips were delivered in late 1970. In mid 1971 Busicom, which had exclusive right to the design and its components, asked Intel to lower their prices.[4] Intel renegotiated their contract and Busicom gave up its exclusive rights to the chips.[4]

A few months later, on November 15, 1971, Intel announced the immediate availability of the first microprocessor chipset family, the MCS-4 micro computer set (all from the Busicom design) with an advertisement in Electronic News.

Broughtons of Bristol

Broughtons of Bristol is a company selling and maintaining a broad line of business machines. They used to buy most of their equipment from Busicom and bought their trade name when they went bankrupt in 1974.


  1. Augarten S.: Bit by Bit, page 261, Ticknor & Fields, 1984
  2. Stine, G.H., The Untold Story of the Computer Revolution, page 163, Arbor House, 1985
  3. Augarten S.: Bit by Bit, page 262-263, Ticknor & Fields, 1984
  4. a b c Reid, T.R.: The Chip, page 141-142, Simon and Schuster, 1984
  5. Busicom 141-FP
  6. Calculateur Busicom HL-21
  7. Pocket-size calculator Busicom LE-120A "HANDY-LE"
  8. Augarten S.: Bit by Bit, page 263-265, Ticknor & Fields, 1984
  9. 1969 - Schottky-Barrier Diode Doubles the Speed of TTL Memory & Logic Computer History Museum. Retrieved September 23,2011.
  10. Agreement between Intel & NCM

See also

  • Intel 4004

External links

de:Busicom es:Busicom fr:Busicom ja: pl:Busicom ru:Busicom

Source: Wikipedia | The above article is available under the GNU FDL. | Edit this article

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