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TI CALCULATOR HISTORY
1972-1980

(since April 22, 1997)

Last Update: October 02, 2021 -- THE CURTA REFERENCE


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1967

TI invents the world’s first handheld electronic calculator.
While small enough to fit into the palm of a hand, the Cal-Tech is powerful enough to perform basic math functions.

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1972

TI’s first handheld calculator hits the retail market.
The revolutionary technology of the single-chip TI-2500 Datamath™ calculator makes everyday math accessible. Capable of performing addition, subtraction, multiplication and division, it features a red, eight-digit LED display.

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1972

TI’s first slide rule calculator.
The SR-10 featured a square root and exponential notation.

Calculator-1972-TI-SR10-Pocket-LED-Calculator-Slide-Rule-Calculator-14592862578_11250c552c_o-tn.jpg
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1974

TI introduces its first scientific calculator.
The TI SR-50 adds trigonometric and hyperbolic functions to the technology available on the TI-2500 Datamath™ calculator, as well as logarithms and their inverses.

More History at Other Later LCD Models page


      SR-10 - 1st
        FUNCTIONS:	Four w/Exponent, square root, square, reciprocal
        MEMORIES:	None
        DISPLAY:	12 LEDs
        KEYBOARD:   23 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  3-AA NiCads (internal)
        PHYSICAL:	6.3" x 3.1" x 1.5"
        WEIGHT:	10 ounces
        PRODUCTION:	1972
        COST:	$149.95
        INFO:	o The "SR-10" logo is situated in the escutcheon 
          surrounding the display.
        o TI's first "SR" (Slide Rule) model.
        o This was a big hefty unit. Hardly hand-held.

    * SR-10 - 2nd
        FUNCTIONS:	Four w/Exponent, square root, square, reciprocal
        MEMORIES:	None
        DISPLAY:	12 LEDs
        KEYBOARD:   23 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  3-AA NiCads (internal)
        PHYSICAL:	6.3" x 3.1" x 1.5"
        WEIGHT:	10 ounces
        PRODUCTION:	1973
        COST:	$89.99
        INFO:	o The "SR-10" logo is situated in the upper area of 
          the faceplate.

    * SR-11
        FUNCTIONS:	Four w/Exponent, square root, square, reciprocal and pi
        MEMORIES:	None
        DISPLAY:	12 LEDs
        KEYBOARD:   24 buttons
        SWITCHES:   Top Right On/Off
                    Top Right keyboard Constant
        BATTERIES:  3-AA NiCads (internal)
        PHYSICAL:	6.3" x 3.1" x 1.5"
        WEIGHT:	9 ounces
        PRODUCTION:	Announced September 11, 1973
        COST:	$119.95 intitially, $79.95 later
        INFO:	o The Sr-11 was like the SR-10, but with pi and a constant.
        o Much less hefty than the SR-10.

      TI-15
        FUNCTIONS:	Four plus 1/X, X*X, Square Root of X, Pi
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	~9 volt
        PHYSICAL:	~5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	German model
        INFO:	o Info from Thomas Brockmeier

      SR-16
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	12 LEDs
        KEYBOARD:   31 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  
        PHYSICAL:	6.3" x 3.1" x 1.5"
        WEIGHT:	8.3 ounces
        PRODUCTION:	Introduced on October 25, 1974
        COST:	$99.95
        INFO:	o The SR-16 was a Scientific calculator.
        o Superseded by the SR-16II within a year.

    * SR-16 II
        FUNCTIONS:	Scientific:
        x^2, sqrt(x), 1/x, y^x, e^x, LNx, Log, One memory 
        register with store, recall, and sum.
        MEMORIES:	1
        DISPLAY:	12 LEDs
        KEYBOARD:   31 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  3-AA NiCads
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	8.25 ounces
        PRODUCTION:	Introduced on August 1, 1975
        COST:	$49.95
        INFO:	o Possibly the last TI slide rule calculator that did 
        not have trig functions.

      SR-20
        AC only version of the SR-22
        SR-20 was a slightly advanced desktop calculator.  
        It had an x! key.  

      SR-22
        FUNCTIONS:	Four plus octal, decimal and hexadecimal conversion
        MEMORIES:	
        DISPLAY:	12 neon gas discharge display (10 + 2)
        KEYBOARD:	34 buttons
        SWITCHES:   Right Side On/Off
        Left-Center of Keyboard AUTO/MAN Base Change
        BATTERIES:  
        PHYSICAL:	9.0" x 6.5" x 2.75"
        WEIGHT:	
        PRODUCTION:	Announced on September 11, 1973
        COST:	$350 plus $50 for the battery pack
        INFO:	o The SR-22 hexadecimal calculator, It converts between 
                      octal, decimal and hexadecimal.  
        o There are 3 LEDs in the keypad area which light to 
          indicate which base you are working in. 
        o A very unique feature is that these conversions are 
          performed on floating-point numbers, not integers. 
                    o For example decimal 2.5 converts to 2.8 in hexadecimal 
          and 2.4 in octal. (from Mike Sebastian)
            o The conversions are very slow, like several seconds.
            o Its color scheme was much like that of the SR-11, with
              white, grey, blue, and orange keys.
            o The ad text reads:
                model SR-20 desk calculator with 14-character display has eight special
                function keys--pi, epsilon, exponent, factorial. integral [integer portion
                of x], square root, squaring, reciprocal, [$]179.95.

                The key layout in the photo are

                INT x   pi      e       EE      CD      C

                x^2     7       8       9       x       / [divide]
                \/x     4       5       6       +       -
                x!      1       2       3       +       -
                1/x     0       .       +/-     =       =

                +, -, and = are double-size keys.  
                CD, C, and 1-9 are white; = is orange.
                Keys on left and remainder on top row are blue.  
                All other keys are grey.
                    from Jeff Woolsey <woolsey@jlw.com>

      TI 25
        Functions: Scientific
        Memories: 1
        Display: 9 LCDs (8 + 1 or 5 + 2 + 2)
        Keybord: 40 buttons
        Switches: None (Key 4 = OFF, Key 5 = ON/C)
        Batteries: 2 Silveroxid (3 V)
        Pysical: 5.2" x 3.0" x 0.4"
        Weight: 80 g
        Production: 1978
        cost: 75 DM in Germany
        INFO: can almost the same as the TI 30, but has no hyperbolic
            functions, therefore 1 dim statistic
      totally black body
      fixed in a map like the typical Japanese calculator 

    * TI-30
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	5.25 ounces
        PRODUCTION:	1976
        COST:	$24.95
        INFO:	o The best selling calculator ever.

      TI-31
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	~9 volt
        PHYSICAL:	~5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	
        INFO:	o Info from Thomas Brockmeier

      TI-33
        FUNCTIONS:	Scientific
        MEMORIES:	3 (thanks Andre from Wuppertal, Germany)
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	~9 volt
        PHYSICAL:	~5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	
        INFO:	o Info from Thomas Brockmeier

      TI-38
        Constant Memory (in beautiful black, I remember there was
        another color, maybe silver) was made in Italy, the number is 4179 PCI,
        so perhaps the correct year might be 1979.
        from Achim (alewand@forwiss.uni-erlangen.de) 

    * SR-40
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	2-AA NiCads to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	5.74 ounces
        PRODUCTION:	1976
        AVAILABLE:	Easy
        INFO:

      TI-41
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	2-AA NiCads to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	
        INFO:	o Info from Thomas Brockmeier

      TI-42 MBA
        FUNCTIONS:	Scientific/Business
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off 
        BATTERIES:	~2-AA NiCads to 9 volt
        PHYSICAL:	~5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	
        INFO:	o Info from Thomas Brockmeier

      TI-45
        FUNCTIONS:	Scientific
        MEMORIES:	1
        DISPLAY:	9-digit fluorescent blue-green display (not ~12 LEDs)
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:	~2-AA NiCads to 9 volt
        PHYSICAL:	~5.8" x 3.2" x 1.4"
        WEIGHT:	~5.74 ounces
        PRODUCTION:	1978
        AVAILABLE:	
        INFO:	o Info from Thomas Brockmeier
                o Jan Kronlund from Finland has a TI-45 with a blue 
                    electrolumicent display
                  Jens-Eike Hartwig (j-e_hartwig@t-online.de) used a 
                  TI-45 in 1978 (at school, 8th grade). 
                  Has a 9-digit fluorescent green display (8 digits + sign/DRG-symbols)
                o Per Hilton from Asker, Norway            
                    Display is not LED, but VFD (Vacuum Fluorescent), 9 digits.
                    Same functions as TI-30, but no power-saving "walking dot" mode 
                      (just turns off after around 7 minutes).
                    Chip is TMC1983NL, display Itron FG95B1.
                    Power consumption (9V) is 25uA when off, 14-15mA when on
                      (vs. 40-60mA for TI-30).

   
    * SR-50
        FUNCTIONS:	Scientific:
        x^2, sqrt(x), 1/x, %, y^x, x root y, factorial, trig,
        hyperbolic trig functions, e^x, LNx, Log, Degrees to 
        Radian conversion and vice versa, degree/radians switch, 
        One memory register with store, recall, and sum.
        MEMORIES:	1
        DISPLAY:	14 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
                    Top Left Radians/Degrees
        BATTERIES:  3-AA NiCads
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	
        PRODUCTION:	Announced on January 15, 1974
        COST:	$169.95
        INFO:	o The first SR-50 was first marketed by direct mail.
        o Like the SR-11, this machine has brightly colored blue, 
          orange, and gray keys, along with white for digit entry. 
        o Also has a silver area that comes down below the first 
          row of keys. 
        o It also marks the start of Texas Instruments assault on
          the HP slide rule calculators.

    * SR-50A
        FUNCTIONS:	Scientific: Same as the SR-50
        MEMORIES:	1
        DISPLAY:	14 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:	3-AA NiCads
        PHYSICAL:	6.0" x 3.2" x 1.3"
        WEIGHT:	8.25 ounces
        PRODUCTION:	1975
        COST:	$109.50
        INFO:	o This model was introduced to standardize this model with
          the SR-52, SR-56, SR-51A to reduce costs. 
        o It also has a more business-like case/key color scheme.
        o Kind of bland compared to the SR-50. 
        o This machine possibly works with the PC-100 series 
          printers.
            o TI-50 Simline LCD serise replaced this popular LED version

    * SR-51
        FUNCTIONS:	Scientific and Financial:
        x^2, sqrt(x), 1/x, y^x, x root y, factorial, permutations, 
        mean, variance, std deviation, Linear regression with 
        trend line projection, random number generator, trig, 
        hyperbolic trig functions, e^x, LNx, Log, 10^x, %, 
        % change, 20 different conversions, degree/radians switch, 
        Three memory registers with full register arithmetic.
        MEMORIES:	3
        DISPLAY:	14 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
                    Top Left Radians/Degrees
        BATTERIES:	3-AA NiCads
        PHYSICAL:	6.0" x 3.2" x 1.3"
        WEIGHT:	8.25 ounces
        PRODUCTION:	Introduced about March of 1975
        COST:	$224.95
        INFO:	o TI replaced the SR-50 and SR-51 in mid-1975 with 
          the "A" models.
        o The SR-51 had been marketed only a few months when 
          this happened, so it's quite rare.  
        o This calculator is also more stylish than any of 
          TI's other advanced models.
        o First machine to offer permutations and a built-in 
          random number generator. 
        o First TI to allow FIX decimal point?
        o This machine also had bright colors like the SR-50.

      SR-51A
        FUNCTIONS:	Scientific and Financial
        MEMORIES:	3
        DISPLAY:	14 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
                    Top Left Radians/Degrees
        BATTERIES:	3-AA NiCads
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	8.3 ounces
        PRODUCTION:	Introduced about March of 1975
        COST:	$224.95
        INFO:	o This model was introduced to standardize this model 
          with the SR-52, SR-56, SR-50A to reduce costs. 
        o It also has a more business-like case/key color scheme.
        o Kind of bland compared to the SR-51.  
        o This machine possibly works with the PC-100 series 
          printers.

    * SR-51-II
        FUNCTIONS:	Scientific and Financial
        MEMORIES:	3
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:	2-AA NiCads to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	7.5 ounces
        PRODUCTION:	1976
        COST:	$80.00
        INFO:

    * TI-51-III
        FUNCTIONS:	Scientific and Financial and Programmable
        MEMORIES:	10
        PRGM STEPS: 32 (and 8 Memories) or 24 (9) or 16 (8)
        DISPLAY:	12 LEDs (8+2+2)
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  2-AA NiCads to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.25 ounces
        PRODUCTION:	1976
        COST:	$80.00
        INFO:	o Programmable
                o Successor of the SR 51 II
                o Same body as TI 57
                o 2 dim statistic with keys for correlation, slope, zero-point, x and y
                o Value convert inch to mm, gal to l, lb to kg, F to C
                o Only rudimentary programmable, therefore programmable functions (R/S,
                  Rst, Lrn, Sst) covers 2nd keys and branches, pause or even backstep
                  doesn't exist.
            
            from Albert Rupprecht <es9j4@yahoo.com> 

            I bought a TI 51 III in spring 1980 because at the age of 13 I didn't
            no the difference to the TI 57. So I thought with more 2nd function
            keys it's the better calculator. TI 51 III and TI 57 had the same
            body, therefore I suppose both were introduced at the same time and
            started with a anodised legend witch later became a plastic relief
            (like my model). The manual's handbook copyright is from 1977 and my
            model looks like the one on your TI 55 photo - so the TI 55 possible
            called TI 51 III in Germany (by the way: I can't remember a TI 55). I
            would talk about a scientific and statistic calculator because it
            hasn't got any financial functions! Unlike the TI 57 it doesn't carry
            the letters "Programmable" because it hasn't got X=T, X>=T, Label, SBR
            or even BST! For having a Pause the manuel suggests using 10 times "="
            then you can see the result flickering!
            But - that must be said - it calculated well, much better as the TI 55
            II from 1982 I bought next. This model was so worse that I though it
            away at last! First I discover a disastrous round mistake (by convert
            DMS to DD) and then using the keys was impossible - the display show
            either nothing or too much of the same numbers - like so many TI
            calculators of this time.
            About the other calculators I don't know much, but the TI 57 had 50
            (not 150) steps and the TI 58 480 and no memories or 8 less per
            memory! Also the TI 59 (960 - 100 to 120 - 0). You shout mentioned
            that the magnetic card reader was integrated and - this was very
            clever and useful - the card's backside could be used as labels for
            the softkeys A to E!. 
            Surly also worth to mention: The TI 30 wrote "Error" with its display.
            And the 3 to 9 V battery pack didn't offer a overcharge-protection, so
            the user could destroy the pills very easily.
            And TI sold the models TI 25 and TI 53 in Germany - they had perhaps
            another name in the USA! These LCD-models existed already in early
            1979, so they might came out in autumn 1978:

    * SR-52
        FUNCTIONS:	Scientific and Programmable:
        224 program steps, Card reader, 20 memories (see below), 
        full log, trig, and algebraic functions. Program steps 
        are completely unmerged. To store a number into memory 1 
        requires 3 steps. STO, 0, 1. 
        MEMORIES:	20
        PRGM STEPS: 224
        STORAGE:	2 7/8-inch by 5/8-inch magnetic cards
        DISPLAY:	14 LEDs
        KEYBOARD:   45 buttons
        SWITCHES:   Top Right On/Off
        Top Left Redians/Degrees
        BATTERIES:  
        PHYSICAL:	
        WEIGHT:	12.3 ounces
        PRODUCTION:	Introduced September 16, 1975
        COST:	$395
        INFO:	o The SR-52 was an early and popular programmable 
          scientific calculator.  
        o An optional printer, the PC-100, was introduced 
          January 7, 1976.
        o First TI programmable, First programmable to offer 
          Indirect addressing (Which I think was a big 
          milestone), and to branch on an error?, 
                      first TI with AOS and parentheses, 
        o Thickest TI ever made. 
        o Sure uses the INV key a lot.
        o This machine had a few goodies built-in to it that 
          many people did not know about. 
          --Memories 98 and 99 were full memories in 
            addition to the 00-19 memories. 
          --Also, storing into memory locations 70 and 
            above stored into program memory. 
          --Storing into memories 60-69 affects pending 
            operations stack. You could get a total of 
            over 50 memories on this machine. 
        o Case design is similar to the SR-50A, 51A, and 56.

    TI 53
        FUNCTIONS: Scientific and Programmable
        MEMORIES: 1 (I'm not sure!!!)
        PRGM STEPS: 32 
        DISPLAY: 9 LCDs (8 + 1 or 5 + 2 + 2)
        KEYBOARD: 40 buttons
        SWITCHES: None (Key 4 = OFF, Key 5 = ON/C)
        BATTERIES: 2 Silveroxid (3 V)
        PHYSICAL: 5.2" x 3.0" x 0.4"
        WEIGHT: I suppose 80 g
        PRODUCTION: 1978
        COST: ?
        INFO: Constant Memory, same body as TI 25 but in silver
              no statistic functions
              only rudimentary programmable, programmable keys 
              are R/S, Rst, Lrn, SST fixed in a map

      TI-54
        Exists -- Need info  

    * TI-55
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	10
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:	2-AA NiCad to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.5 ounces
        PRODUCTION:	1977
        COST:	
        INFO:	o Budget scientific model.

      TI-55II
        scientific slimline w/angled LCD display
        
      SR-56
        FUNCTIONS:	Scientific:
        Full log, trig, and algebraic functions. 
        MEMORIES:	10
        PRGM STEPS: 100
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        Top Left Gradent/Degrees
        BATTERIES:  
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	8.3 ounces
        PRODUCTION:	Announced on January 21, 1976
        COST:	$179.95
        INFO:	o Works with PC-100 and 100A printer.
        o First TI key programmable.
        o First TI since the SR-50 not to include factorial. 
        o First TI to include a Pause function. 
        o First programmable to use an independent test 
          register for branching?
        
      SR-56 Programmable
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	10
        PRGM STEPS: 100
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        Top Left Gradent/Radians/Degrees
        BATTERIES:  
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	8.3 ounces
        PRODUCTION:	
        COST:	$139.00
        INFO:

    * TI-57 type 1
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	8
        PRGM STEPS:	150, Key programmable
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  2-AA NiCad to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.5 oz
        PRODUCTION:	Introduced on May 24, 1977
        COST:	$79.95
        INFO:	o The TI-57 superseded the SR-56.
        o TI legend anodized on aluminum.
        o Most people do not know that any TI-57 can be made 
          into a TI-57C by sacrificing the last two program 
          steps.  Program memory is retained at little or no 
          battery drain, but unit is NOT switched off. 
          How?: At step 48 of your program memory, place the 
          following: 2nd Exc SST LBL 1.  Press LRN. When you 
          want to switch your calculator off, press GTO 2nd 
          48, R/S, INV STO 3 +/- +/-.  The display will go 
          blank.  It uses even less energy than the TI-58C 
          to store programs this way.  When you want to 
          switch the calculator back on, press INV FIX CLR.
          Try it.

    * TI-57 type 2
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	8
        PRGM STEPS:	150, Key programmable
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  2-AA NiCad to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.25 oz
        PRODUCTION:	Introduced on May 24, 1977
        COST:	$79.95
        INFO:	o The TI-57 superseded the SR-56.
        o TI legend in plastic relief

    * TI-58
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	60
        PRGM STEPS: 480, Key programmable
        DISPLAY:	12 LEDs
        KEYBOARD:   45 buttons
        SWITCHES:   Top Left On/Off
        BATTERIES:	3-AA NiCads
        PHYSICAL:	6.4" x 3.2" x 1.5"
        WEIGHT:	8.5 ounces
        PRODUCTION:	Introduced on May 24, 1977
        COST:	$124.95
        INFO:	o Replaced with the 58C in 1979
        o One of the last key programmables that lost 
          program memory when turned off.  This significantly 
          lowers its value and usefulness.
        o First machine to use ROM cartridges. 
        o This machine has the ability to run programs in 
          fast mode. Speeds execution by about 25%.

    * TI-58C
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	60 or
        PRGM STEPS: 480, Key programmable.
        DISPLAY:	12 LEDs
        KEYBOARD:   45 buttons
        SWITCHES:   Top Left On/Off
        BATTERIES:  
        PHYSICAL:	6.4" x 3.2" x 1.5"
        WEIGHT:	8.5 ounces
        PRODUCTION:	1979
        COST:	
        INFO:	o Model 58 with continuous memory.
        o Works with PC-100A and 100C printer.
        o Corrects the primary deficiency of the TI-58 in 
          that it remembers memory when turned off!
        o First machine to use ROM cartridges. This machine has 
          the ability to run programs in fast mode. Speeds 
          execution by about 25%.

    * TI-59
        FUNCTIONS:	Scientific and Programmable
        MEMORIES:	100 or
        PRGM STEPS: 960
        STORAGE:	Magnetic cards
        DISPLAY:	12 LEDs
        KEYBOARD:   45 buttons
        SWITCHES:   Top Left On/Off
        BATTERIES:	2-AA NiCad
        PHYSICAL:	6.4" x 3.2" x 1.5"
        WEIGHT:	10 ounces
        PRODUCTION:	Introduced on May 24, 1977
        COST:	$299.95
        INFO:	o Modules containing programs with up to 5000 steps 
          were available for this calculator. 
        o A magnetic card reader was available.
        o Surprisingly common, given its expense and 
          sophistication.  
        o Works with PC-100A and 100C printer.
        o Largest memory capacity of ANY programmable until 
          HP-41C introduced.
        o First machine to use ROM cartridges. 
        o Card readers on these units are notoriously unreliable. 
        o First machine to use ROM cartridges. 
        o This machine has the ability to run programs in fast
          mode.  Speeds execution by about 25%.

      SR-60A (Scientific Desktop)
        FUNCTIONS:	Scientific
        MEMORIES:	100
        PRGM STEPS: 480/1920
        DISPLAY:	20 LEDs
        KEYBOARD:   95 keys
        SWITCHES:   
        BATTERIES:  AC power
        PHYSICAL:	Desktop
        WEIGHT:	~26 lbs
        PRODUCTION:	1976
        COST:	1695.00
        INFO:	o Card Reader and Printer built in
        o Desktop card programmable. 
        o Had over 2000 program steps when expanded and 
          prompted with alpha characters.

      TI-88
      Date Introduced: Never.
      Price: N/A
      Functions:
      Info:	o TI equivalent to the HP-95C!
        o Biggest hyped vapor-calc ever. 
        o This was to be the TI response to the HP-41C.
        o Had alpha, etc.
        o Hyped to many TI-59 owners, but then withdrawn 
          without comment.
        o Obviously very rare. If you ever find one, buy it.

            from Arthur Hagen <art@broomstick.com>

            Also, I'm one of the lucky few who has actually put my hands on a TI-88.
            It came (or didn't, as it turned out) with two slots in the rear, for
            expansion, and was clearly meant to hit the same market as the HP-41.
            Unfortunately, the TI representative wouldn't let me buy the demo model.

      TI-95 PROCALC.
        FUNCTIONS:	Scientific
        MEMORIES:	8k memory expandable to 16k
        PRGM STEPS: Fully programmable
        DISPLAY:  15 character by 2 line dot matrix display
                  Second line in display used as 5 "soft labels"	
        KEYBOARD: 65 keys: 21 math keys
                  5 programmable function keys
                  9 top menu keys
        SWITCHES:   
        BATTERIES:  
        PHYSICAL: 8" X 3.75" X 1" size
        WEIGHT:	
        PRODUCTION:	Manufactured 1986
        COST:	
        INFO:	o i/o port
                o cartridge port
                o hard shell case
                o available accessories
                  : tape interface, 
                  : thermal printer, 
                  : rom and ram cartridges.
        Notes: based on tms 1000 cpu, used a lot of nested menus for functions.
        programming used an extended version of AOS and even allowed direct
        execution of ml programs routines. 
    
        A similar calculator called the BasicCalc with different roms and
        keyboard was released at about the same time.
        It runs BASIC, holds 8k of memory, a maximum of 16k.  It has 113 instructions.

      TI-150
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	xx Orange Vacuum-fluorescent
        KEYBOARD:	19 buttons
        SWITCHES:   Top Right On/Off
        Top Left Decimal Point Adjust
        BATTERIES:  4-AA
        PHYSICAL:	6.5" x 3.2" x 1.8"
        WEIGHT:	10 ounces
        PRODUCTION:	1974
        COST:	
        INFO:	o Possibly the rarest TI.  
        o The keys and body style of the 2550, painted-on 
          silver trim of SR-10.
        o No memory or fixed decimal switch as on 2550.  
        o Unusual orange display.

    * TI-1000 type I
        FUNCTIONS:	Four, plus percentages
        MEMORIES:   None
        DISPLAY:	8 LEDs
        KEYBOARD:   20 buttons
        SWITCHES:   None
        BATTERIES:  9 volt
        PHYSICAL:	5.4" x 2.9" x 1.3" 
        WEIGHT:	4.5 oz
        PRODUCTION:	1977
        COST:	$9.77
        INFO: 	o Gold trim

    * TI-1000 type II
        FUNCTIONS:	Four, plus percentages
        MEMORIES:   None
        DISPLAY:	8 LEDs
        KEYBOARD:   20 buttons
        SWITCHES:   None
        BATTERIES:  9 volt
        PHYSICAL:	5.4" x 2.9" x 1.3" 
        WEIGHT:	4.5 oz
        PRODUCTION:	1977
        COST:	$9.77
        INFO:	o Brown trim

    * TI-1025
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	1
        DISPLAY:	8 Vacuum-fluorescent
        KEYBOARD:   24 buttons
        SWITCHES:   None
        BATTERIES:	9 volt
        PHYSICAL:	5.4" x 2.9" x 1.3"
        WEIGHT:	5.25 ounces
        PRODUCTION:	1977
        COST:	$11.77
        INFO:	o Often found with in the origional box.

      TI-1050
        FUNCTIONS:	Four, plus percentage and square root
        MEMORIES:   2 KEY MEMORY
        DISPLAY:	8 Blue Vacuum-fluorescent
        KEYBOARD:	24 buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 3.0"
        WEIGHT:	
        PRODUCTION:	1977
        COST:	$12.95
        INFO:	o Another entry in the 1000/1025 line.
        o Automatic Constant

    * TI-1200
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:   19 buttons
        SWITCHES:   Left Side On/Off
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.8" x 1.4"
        WEIGHT:	5.5 oz
        PRODUCTION:	1975
        COST:	$14.88
        INFO:	o Often found in the origional box.
        o The 1200 series styling was used on many other TI 
          calculators and they all shared the annoying 
          characteristic of loose or missing faceplates.

      TI-1200 "Lady"
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:	19 buttons
        SWITCHES:   Left Side On/Off
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.8" x 1.4"
        WEIGHT:	5.5 ounces
        PRODUCTION:	1975?
        COST:	
        INFO:	o The 1200 with more "feminine"-colored faceplate and keys.

      TI-1205
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	
        INFO:	o Another colorful 1200 relation, but this one has 
          oversized lettering too.

      TI-1220 (T-1220)
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	
        INFO:	o This (and the 1225) are somewhat obscure, but 
          otherwise ordinary, 1200 series units.

      TI-1225 (T-1225)
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	
        INFO:

    * TI-1250
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   24 buttons
        SWITCHES:   Left Side On/Off
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.8" x 1.4"
        WEIGHT:	5.5 oz
        PRODUCTION:	Introduced on June 1, 1975
        COST:	$24.95
        INFO:

      TI-1255
        It has a bright blue (darker than the Lady 1200) face plate 
        and an ivory colored case (same as the Lady 1200).  Oddly, the rear label 
        which is black states that it is a TI-1250 but the face plate has TI-1255 on 
        it. from Cleo McCall (ApexMcCall@aol.com )

      TI-1265
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx Blue Vacuum-fluorescent
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.8" x 1.4"
        WEIGHT:	
        PRODUCTION:	Introduced on April 9, 1976
        COST:	
        INFO:	o Has a Blue florescent display, unique within the
          1200 series.

    * TI-1270
        FUNCTIONS:	Four, plus reciprocal, square, square root, and pi
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   24 buttons
        SWITCHES:   24
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.8" x 1.4"
        WEIGHT:	5.5 oz
        PRODUCTION:	Introduced on April 21, 1976
        COST:	$18.95
        INFO:	o The TI-1270 was designed for use in secondary schools.
          Colorful model.  
        o TI appeared to like orange.

      TI-1400
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	None
        DISPLAY:	xx LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	
        INFO:	o Has a brown carrying case, not the usual black.
        o Similar styling to the 1200.

      TI-1450
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	$16.00
        INFO:

    * TI-1500
        FUNCTIONS:	Four, plus percent
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:   19 buttons
        SWITCHES:   Top Middle Left On/Off
        BATTERIES:  2-AA NiCads (internal)
        PHYSICAL:	5.0" x 2.6" x 1.0"
        WEIGHT:	7 ounces
        PRODUCTION:	Introduced April 8, 1974
        COST:	$69.95, later lowered to $59.95
        INFO:	o Nifty little unit with thick chrome borders.

      TI-1600
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	None
        DISPLAY:	8 Blue Vacuum-fluorescent
        KEYBOARD:   20 buttons
        SWITCHES:   
        BATTERIES:  xx NiCad
        PHYSICAL:	5.0" x 3.0"
        WEIGHT:	
        PRODUCTION:	Introduced on June 13, 1976
        COST:	$24.95
        INFO:	o The 1600 series consisted of slimmed-down models that 
          preconfigured the styling of LCD units.

      TI-1650
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	yes
        DISPLAY:	xx Blue Vacuum-fluorescent
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  xx NiCad
        PHYSICAL:	5.0" x 3.0"
        WEIGHT:	
        PRODUCTION:	Announced June 13, 1976
        COST:	$29.95
        INFO:

      TI-1680
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	1, plus 20 line recall
        DISPLAY:	8 Blue Vacuum-fluorescent
        KEYBOARD:	24 buttons
        SWITCHES:   None
        BATTERIES:  xx NiCad
        PHYSICAL:	5.0" x 3.0"
        WEIGHT:	
        PRODUCTION:	Introduced on June 5, 1977
        COST:	$29.95
        INFO:	o The TI-1680 could re-display up to 20 past numbers 
          on its display, instead of having a printer.
        o Allowed some primitive editing of those entries.

      TI-1700 - DataClip
        FUNCTIONS:	Four plus percentage
        MEMORIES:	1
        DISPLAY:	8 LCDs
        KEYBOARD:   22 buttons
        SWITCHES:   None
        BATTERIES:  Three Silver Oxide
        PHYSICAL:	About the proportions of a six-inch ruler
        WEIGHT:	
        PRODUCTION:	Announced on June 5, 1977
        COST:	$34.95
        INFO:	o LCD calculator shaped like a 6-inch ruler.  
        o High quality, unlike its many knockoffs.

    * TI-1750 (1st LCD)
        FUNCTIONS:	Four, plus square root and percentages
        MEMORIES:	4 key memory
        DISPLAY:	8 LCDs
        KEYBOARD:	24 buttons
        SWITCHES:   Top Left below display On/Off
        BATTERIES:  Two silver oxide 
        PHYSICAL:	4.5" x 2.7" x .4"
        WEIGHT:	less than 2.5 ounces
        PRODUCTION:	Introduced in mid-April of 1977
        COST:	$24.95 
        INFO:	o TI's first LCD calculator.
      
    TI-1790 Data Chron
      FUNCTIONS:   Four plus square root and  percentage
      MEMORIES:    One
      DISPLAY:     8 LCDs plus day of week
      KEYBOARD:    25 buttons
      SWITCHES:    Time set , alarm set am,pm start/stop lap/reset,time call ,day ,date, time
      BATTERIES:   2 ea G13
      PHYSICAL:    2 5/8 "x 5 5/8 x 3/8
      WEIGHT:      4.3 oz with case
      PRODUCTION:  Introduced January 5, 1978
      COST:        $50
      INFO:        o The DataChron calculator incorporated a watch with
                      stopwatch and alarm.
      TI-2000
        FUNCTIONS: Four
        MEMORIES: None
        DISPLAY: 7 LEDs (RED)
        SWITCHES: Top left side On/Off
        BATTERIES: 3x AA
        PHYSICAL: 13cm tall, 7cm wide, 3.5cm thick
        PRODUCTION: ~1974
        INFO: The face plate is orange with a black TI-logo in the upper-left
              corener, and silver lettering for the model ("TI-2000" in the
              upper-right corner), and in silver the word "ON" right below 
              the on/off switch which is below the TI-logo.
                from Eric (itdept@altrex.nl)
        The key layout:
            [on/off][C] [/]
            [7] [8] [9] [x]
            [4] [5] [6] [-]
            [1] [2] [3] [+]
            [CE][0] [.] [=]

   
      TI-2500 Datamath - 1st
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:	18 buttons
        SWITCHES:	Top Left Side On/Off
                    Chain/Constant switch
        BATTERIES:	4-AA NiCads (internal)
        PHYSICAL:	5.5" x 3.0" x 1.7",
        WEIGHT:	12 ounces
        PRODUCTION:	Introduced September 21, 1972
        COST:	$119.95
        INFO:	o Four and a half hours battery life were claimed.
        o The TI-2500 was TI's first hand calculator. 
        o It was introduced along with the TI-3000 and 
          TI-3500 desk-top calculators.
        o This model states a recharging time of 16 hours 
          on the back plate.
        o Two screws hold the battery compartment hatch on.
            o A LCD version of the Datamath called the Minimath.
              It was a prototype and never released.
              
    * 2500 Datamath - 2nd
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:   18 buttons
        SWITCHES:   Top Left Side On/Off
                    Chain/Constant switch
        BATTERIES:  4-AA NiCads (internal)
        PHYSICAL:	5.5" x 3.0" x 1.7"
        WEIGHT:	12 ounces
        PRODUCTION:	1973
        COST:	$119.95
        INFO:	o This model states a recharging time of 10 hours on 
          the back plate.
        o No battery compartment hatch, have to remove entire back.

    * TI-2500 Datamath-3rd - same as TI-2500B Datamath
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:   18 buttons
        SWITCHES:   Top Left Side On/Off
                    Chain/Constant switch
        BATTERIES:  4-AA or 3-NiCads (internal)
        PHYSICAL:	5.5" x 3.0" x 1.7"
        WEIGHT:	12 ounces
        PRODUCTION:	
        COST:	
        INFO:	o Nice, quarter turn access to battery compartment hatch.

      Longines Symphonette (2500)
        INFO:	o Just like the three types of the 2500.

    * TI-2500-II
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   Top Left Side On/Off
                    Chain/Constant switch
        BATTERIES:  2-AA
        PHYSICAL:	5.5" x 3.0" x 1.7"
        WEIGHT:	12 ounces
        PRODUCTION:	Introduced November 11, 1974
        COST:	$49.95
        INFO:	o Similar to the 2500 but has a % key and cheap logo 
          strip that tends to peel off.
        o With a battery hatch?

    * TI-2510
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:	xx buttons
        SWITCHES:   Top Left Side On/Off
                    Chain/Constant switch
        BATTERIES:  4-AA
        PHYSICAL:	5.5" x 3.0" x 1.7"
        WEIGHT:	12 ounces
        PRODUCTION:	1973
        COST:	$39.95
        INFO:	o Similar to 2500, but chronologically sandwiched 
          somewhere between the 2500 and 2500-II, probably 
          failing to land a market niche in TI's crowded 
          product line.  
        o Calculator body is a lighter cream shade compared 
          to 2500's beige.  
        o Uses disposable batteries.
        o Nice, quarter turn access to battery compartment hatch.

    * TI-2550
        FUNCTIONS:	Four, plus percentage
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   23 buttons
        SWITCHES:   Top Right On/Off
        Top Left Decimal Point Adjust
        BATTERIES:  3-AA NiCads or 4-AAs
        PHYSICAL:	6.5" x 3.2" x 1.8"
        WEIGHT:	10 ounces
        PRODUCTION:	Introduced on January 10, 1974
        COST:	$99.95, later down to $69.95
        INFO:

    * 2550-II
        FUNCTIONS:	Four, plus square root, square, reciprocal, and percent
        MEMORIES:	1
        DISPLAY:	8 Vacuum-fluorescent
        KEYBOARD:	27 buttons
        SWITCHES:   Top Right On/Off
                    Top Left F/2 Digit 
        BATTERIES:  3 NiCad
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	about 8 ounces
        PRODUCTION:	Introduced on October 17, 1975
        COST:	$49.95
        INFO:

      TI-2550-III
        FUNCTIONS:	Four, plus square root, square, reciprocal, and percent
        MEMORIES:	1
        DISPLAY:	8 Green Vacuum-fluorescent
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  
        PHYSICAL:	5.8" x 3.2" x 1.3"
        WEIGHT:	about 8 ounces
        PRODUCTION:	1976
        COST:	$29.95
        INFO:

      TI-2550-IV
        FUNCTIONS:	Four, plus Playback
        MEMORIES:	1
        DISPLAY:	8 Green Vacuum-fluorescent
        KEYBOARD:	24 buttons
        SWITCHES:   None
        BATTERIES:  
        PHYSICAL:	~5.8" x 3.2" x 1.3"
        WEIGHT:	~about 8 ounces
        PRODUCTION:	1978
        COST:	$
        INFO:	o Info from Thomas Brockmeier

      TI-3500
        Need Info
      
      TI-4000
        twelve digits with commas, and a memory

      TI-5025 (printer)
        FUNCTIONS:	Four plus percentage
        MEMORIES:	1
        DISPLAY:	8 Vacuum-fluorescent
        KEYBOARD:   24 buttons
        SWITCHES:   
        BATTERIES:  xx NiCad
        PHYSICAL:	7.0" x 3.5"
        WEIGHT:	
        PRODUCTION:	1979
        COST:	$89.95
        INFO:	o Portable Display Printer

    * TI-5040
        FUNCTIONS:	Four
        MEMORIES:	1
        DISPLAY:	10 Blue Vacuum-fluorescent
        KEYBOARD:   27 keys
        SWITCHES:   Right side, On/Off
        Top right keyboard, F/A format
        BATTERIES:  AC power
        PHYSICAL:	9.4" x 9.25" x 3.0"
        WEIGHT:	~5 lbs
        PRODUCTION:	1977
        COST:	$129.95
        INFO:	o Common desktop model with printer.

      TI-5050
        FUNCTIONS:	Four plus percentage
        MEMORIES:	
        DISPLAY:	None, Paper Tape only
        KEYBOARD:	xx buttons
        SWITCHES:   
        BATTERIES:  xx NiCad
        PHYSICAL:	8.7" x 3.9" x 2.7"
        WEIGHT:	28 ounces
        PRODUCTION:	Introduced on March 24, 1975
        COST:	$199.95
        INFO:	o The TI-5050 was a printing calculator.  It printed 
          on two-inch wide paper.
        o Handheld printing unit with memory.

      TI-5050M
        FUNCTIONS:	Four plus percentage
        MEMORIES:	
        DISPLAY:	None, Paper Tape only
        KEYBOARD:	23 buttons
        SWITCHES:   
        BATTERIES:  xx NiCad
        PHYSICAL:	8.5" x 4.0
        WEIGHT:	
        PRODUCTION:	1976
        COST:	$99.95
        INFO:

      Able IV
        FUNCTIONS:	Four plus percentage
        MEMORIES:	None
        DISPLAY:	xx LEDs
        KEYBOARD:   16 buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.5" x 2.75"
        WEIGHT:	
        PRODUCTION:	1976
        COST:	
        INFO:	

    * Business Analyst
        FUNCTIONS:	Business
        MEMORIES:	None
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:  9 volt rechargable pack
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.25 oz
        PRODUCTION:	Introduced on June 13, 1976
        COST:	$49.95
        INFO:	o The first in a long line of financial calculators.

    * Business Analyst I
        FUNCTIONS:	Business
        MEMORIES:	None
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:  2-AA NiCad to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	5.5 ounces
        PRODUCTION:	1979
        COST:	
        INFO:

      Concept I
        FUNCTIONS:	Four plus percentage
        MEMORIES:	None
        DISPLAY:	xx LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Concept II
        FUNCTIONS:	Four plus percentage
        MEMORIES:	yes
        DISPLAY:	xx LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   
        BATTERIES:  9 volt
        PHYSICAL:	5.7" x 2.7"
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Exactra 19
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	6 LEDs
        KEYBOARD:   18 buttons
        SWITCHES:   Left, On/Off
        BATTERIES:  3-AA
        PHYSICAL:	5.25" x 3.0
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Exactra 20 (TI-20)
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	6 LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   Left, On/Off
        BATTERIES:  3-AA
        PHYSICAL:	5.25" x 3.0"
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Exactra 21
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	6 LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   Left, On/Off
        BATTERIES:  3-AA
        PHYSICAL:	5.25" x 3.0"
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Exactra 22
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	6 LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   Left, On/Off
        BATTERIES:  3-AA
        PHYSICAL:	
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

      Exactra 23
        FUNCTIONS:	Four
        MEMORIES:	None
        DISPLAY:	6 LEDs
        KEYBOARD:   xx buttons
        SWITCHES:   Left, On/Off
        BATTERIES:  3-AA
        PHYSICAL:	5.25" x 3.0"
        WEIGHT:	
        PRODUCTION:	
        COST:	
        INFO:	

    Exactra 100
        Never released?  

    * MBA
        FUNCTIONS:	Business
        MEMORIES:	12
        DISPLAY:	12 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   Top Right On/Off
        BATTERIES:  9 volt rechargeable
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.5 oz
        PRODUCTION:	Introduced on June 5, 1977
        COST:	$79.95
        INFO:	o This was an early business-oriented machine with 
          several keys for standard business functions.

    * Money Manager
        FUNCTIONS:	Business
        MEMORIES:   
        DISPLAY:	8 LEDs
        KEYBOARD:	40 buttons
        SWITCHES:   None
        BATTERIES:  9 volt NICA
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	5.5 oz
        PRODUCTION:	Introduced on January 13, 1977
        COST:	$26.95
        INFO:	o The Money Manager was aimed at home finance calculatins.

    * PC-100A (printer)	1979	

    * PC-100C (printer)	1979	

    * Programmer
        FUNCTIONS:	Four plus Base math
        MEMORIES:	1
        DISPLAY:	8 LEDs
        KEYBOARD:   40 buttons
        SWITCHES:   None
        BATTERIES:  2-AA NiCad to 9 volt
        PHYSICAL:	5.8" x 3.2" x 1.4"
        WEIGHT:	6.25 ounces
        PRODUCTION:	1978
        COST:	$42.50
        INFO:       This calculator was also produced with a LCD display.
(See the "Other Later LCD Models" page for more information). from Arthur Hagen <art@broomstick.com> The "TI Programmer" exists in two different versions - one with LEDs and one slimmer one with a LCD display. I still use the latter, and it says Copyright 1978 just like the LED version, although it was produced in the early 80's. As for the price, I paid the equivalent of $120 for it when it was new, but prices here in Norway are much higher. * Spirit of 76 FUNCTIONS: Four plus percentage MEMORIES: None DISPLAY: 8 LEDs KEYBOARD: 19 buttons SWITCHES: Left Side On/Off BATTERIES: 9 volt PHYSICAL: 5.5" x 2.8" x 1.4" WEIGHT: 5.5 ounces PRODUCTION: 1976 COST: INFO: o Red/White/Blue Bicentennial (of the USA) model. o Another 1200 progeny. Tax Planner FUNCTIONS: Complete Tax Functions MEMORIES: DISPLAY: xx LEDs KEYBOARD: xx buttons SWITCHES: BATTERIES: 4-AA PHYSICAL: 6.5" x 3.0" WEIGHT: PRODUCTION: 1983 COST: INFO: o (c) Warren, Gorham, & Lambert o Appears to be a highly modified TI-59


More History at Other Later LCD Models page


Special Thanks

Andreas Krause (a-krause2@ti.com)
Gene Wright (gene@theporch.com)
Achim Lewandowski (lewandowski@forwiss.de)
Alan Robinson (trw@iland.net)
Andy E (andye@att.com)
Albert Rupprecht (es9j4@yahoo.com)
Arthur Hagen (art@broomstick.com)
Eric (itdept@altrex.nl)
Shaun (loomis@neo.rr.com)
Doug (alwaysup@att.net)
Sebastian (sebastia@flash.net)
Raymond Flowers (Quadrajet1@aol.com)
Thomas Brockmeier: TI-15 (German), TI-31, TI-33, TI-41, TI-42 MBA, TI-45, and the TI-2550-IV.
Gene Wright - Lots of Info on the Scientific models.



If you should own a model that I have inaccurately or incompletely described then help me to correct and/or fill in the details. Your E-mails and photos are appreciated.





Rick Furr (rfurr@vcalc.net)
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