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CONTEX  -  B

Have a Look INSIDE the CONTEX-B ...
 ``` T E C H N I C A L D A T A of the Mechanical Calculator CONTEX-B ************************************************************************ This Danish calculator is a small and light-weight "HALF-COMPTOMETER" Serial Number: 0203419 Dimensions: (ca.) Width = 9 " / 23 cm Depth = 9 " / 23 cm Height = 2_3/4" / 7 cm Weight: (ca.) 3 lbs / 1.3 kg Mechanics: 8*5 "HALF"-Keyboard, COMPTOMETER-Coding = Instant Additions Functions: Addition, Subtraction ( as 9-Complement Addition ) Registers: Input = 8 Decimals Arithmetic = 9 Decimals Manufacturer: BRDR. CARLSEN Gentofte, Denmark 1960 H O W T O U S E the CONTEX - B ************************************* To CLEAR the REGISTER push the left LEVER down and release it. As mentioned to the "Key-Driven-Calculators" BURROUGHS & COMPTOMETER: Calculator courses suggested to use only the lower-half of the full keyboard to speed-up additions in saving hand/arm motions: instead key 6 press 3 + 3 in sequence 7 3 + 4 8 4 + 4 9 4 + 5 Obviously the method was used, because the lower-half of the keyboard show more wear on most calculators of this type. Consequently CONTEX made a "HALF-COMPTOMETER": Smaller, mechanically less sophisticated, more light-weight and therefore much cheaper than the "big" ones. Because there are no 9-Complements on the keys, do it in this way ... A Subtraction Example: 765 - 432 = 333 ---------------------- o Enter on the right columns "765" o Calculate the SUBTRAHENT MINUS 1 432 - 1 = 431 o Calculate the 9-COMPLEMENTS of "431" = 568 o Hit on the right columns 5 3+3 4+4 o INSTEAD "Press all 9-Keys left of the subtrahend simultaniously": - PRESS all "5"-Keys left of the subtrahend simultaniously and than - PRESS all "4"-Keys left of the subtrahend simultaniously For more information ... ===>>> Have a look at the BURROUGHS site <<<=== R E M A R K S : ======================================================================== Two lines of interesting and innovative mechanical calculators came on the market under the name » CONTEX « in the '50s and '60s : The first was a key-driven adding machine in style of a Comptometer, with a "half" keyboard and simplified mechanism. The CONTEX-A was an "open" version and came either in BAKELITE or in PLASTIC like these: CONTEX-B is the "closed" version. Both adding machines had an unusual design: Most of the internal levers were made out of pressed fibreboard. The second line was a series of 10-Block-Keyboard machines. The model CONTEX-10 is manual. The CONTEX-20 is motor-driven and the CONTEX-30 has improved motor-driven multiplication & division. The CONTEX-55 has its own DIVISION REGISTER to complete the division full automatically. impressum: ************************************************************************ © C.HAMANN http://public.beuth-hochschule.de/~hamann 09/08/07 ```