Texas Instruments TI-1050

Date of introduction:  June 1977 Display technology:  Fluorescent
New price:  $12.95, 9.95 Display size:  8
Size:  5.4" x 2.8" x 1.3"
 138 x 72 x 32 mm3
Weight:  3.5 ounces, 98 grams Serial No:  
Batteries:  9V  Date of manufacture:  wk 40 year 1977
AC-Adapter:  AC9180 Origin of manufacture:  USA (MTA)
Precision:  8 Integrated circuits:  TMC0921
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Introduced together with the TI-1000 this one uses a fluorescent display and some enhanced features. In a direct comparison with the TI-1025 you'll notice the unusual [M], [MR] and [REV]-keys. At first glance you would expect only limited memory functions and an exchange functions between the memory and display known from the TI-2550-III but Colin Douglas Howell located the US Patent Application #4112495.

TI-1050_PCB.jpg (48414 Byte)This patent includes a complete ROM listing of the code in the TMC0921 single-chip calculator circuit used by TI-1050. Unfortunately, the listing is rather poorly printed, but there are a couple other patents, #4100606 and #4287559, which include clearer printouts of the same code. The code, once deciphered, is rather interesting, and it serves as a useful guide to the details of both the TI-1050 and the TI-1025, which used the closely related TMC0923.

This code reveals that the TI-1050's [M] key is a prefix key that allows it to perform various memory operations, including the following:

[M] [CE/C] Clear Memory
[M] [=] Store Display in Memory
[M] [+] Add Display to Memory
[M] [-] Subtract Display from Memory
[M] [x] Multiply Memory by Display
[M] [:] Divide Memory by Display
[M] [REV Exchange Memory with Display

The approach of a memory prefix key was continued with the TI-1680, its twin TMS-2550-IV and the later TI-1070.

The TI-1050 calculators were manufactured either in El Salvador, Hong Kong, Italy or USA.

Calculators with different keyplates were sold from Western Auto as Citation and Koh-i-Noor Hardtmuth as TI-1050.


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If you have additions to the above article please email:

Joerg Woerner, December 5, 2001. No reprints without written permission.