DATAMATH CALCULATOR MUSEUM

Texas Instruments ABLE

Date of introduction:	1976	Display technology:	LED-stick
New price:		Display size:	8
Size:	5.5" x 2.8" x 1.4" 138 x 70 x 35 mm³
Weight:	6.0 ounces, 170 grams	Serial No:	15339
Batteries:	2*AA NiCd	Date of manufacture:	wk 40 year 1977
AC-Adapter:	AC9130	Origin of manufacture:	USA (LTA)
Precision:		Integrated circuits:	TMS0972
Memories:
Program steps:		Courtesy of:	Joerg Woerner
		Download manual:	(US: 4.9 MByte)

The ABLE (ABstract Linking Electronically) electronic calculator was the first effort at an educational calculator for young children (K-1 grade). It continued the design started in cooperation with the Lawrence Hall of Science of the University of California that led to the experimental TI-MEC calculator.

The ABLE was sold complete with:

• One ABLE calculator base unit
• 6 colorful, interchangeable snap-on keyboard faces
• One adapter AC9130 for recharging the built-in NiCd batteries
• One keyboard holder for storage of the 6 ABLE faces

The ABLE calculator base unit is basically a redesign of the TI-1205 and TI-1255 calculators introduced in 1976, too. Main difference is the key mechanism that allows to use one of the 6 limited function keyboard faces. The upper half of the housing sports a concealed button in front of the calculator. Pushing it firmly releases the installed keyboard unit and it can be easily replaced by another one with a simple, positive click.

The ABLE calculator features a set of six interchangeable keyboard faces, with a growing key pattern sequenced as follows:

FACE DESCRIPTION
ABLE-I	[0] – [1], [+], [=], [C]
ABLE-II	[0] – [5], [+], [-], [=], [C]
ABLE-III	[0] – [9], [+], [-], [=], [C]
ABLE-IV	[0] – [9], [+], [-], [x], [.], [=], [C]
ABLE-V	Dot Numerals 0 – 9, [+], [-], [x], [=], [C]
ABLE-VI	[5] – [9], [+], [-], [=], [C]

Disassembling this ABLE calculator manufactured in October 1976 by Texas Instruments in their Lubbock, TX facility reveals an internal construction identical with the TI-1255. Instead of the 9V battery found in the original TI-1200/TI-1250 design, the ABLE calculator makes use of 2 rechargeable, AA-sized NiCd (Nickel Cadmium) batteries. The PCB (printed circuit board) adds both the charging circuit for the batteries and a step-up converter to generate the 9V supply of the TMS0972 single-chip calculating circuit. Please notice that both the Klixon™-style keyboard and the TMS0972 would support the 4-key memory of the TI-1255.

Learn more about the evolution of the TI-1250 between June 1975 and its discontinuation in 1977.

Learn more about the different Product Labels used with the TI-1250 - here at the Datamath Calculator Museum we classify the featured ABLE as Hardware Version 3A, PCB Type 4 and Product Label Style 8.

It took about 30 years before Texas Instruments developed with the TI-Nspire another educational calculator with interchangeable keyboards!

This rare Texas Instruments ABLE calculator was sold on eBay in September 2007 together with two siblings New-In-Box. The three lucky buyers paid US$211.50 (Serial No: 15339), US$151.50 (Serial No: 15379) and US$200 (Serial No: 29276). In December 2007 the Datamath Calculator Museum was able to acquire from the same seller a lot of three "defective" ABLE calculators for US$173.70 (Serial Nos: 10968-LTA3776, 11051-LTA3776 and 29168-LTA4077).

Fellow collectors - if you own a Texas Instruments ABLE calculator, please report us the serial number and date code from the back of the calculator for our Database.

On September 17, 2009 we were able to celebrate reunion of the calculators featured in the TI Learning Center Sales Leaflet CB-272 including three of the rarest portable electronic calculators.

Find here an excerpt from the TI Learning Center leaflet CB-272 dated 1976:

ABLE™. A limited-function calculator with interchangeable keyboard faces.

Texas Instruments rechargeable ABLE calculator was specially designed as a learning aid for arithmetic basics at early elementary levels. Each rugged, solid-state ABLE calculator base unit includes six interchangeable keyboards ranging from a limited-function [0] – [1], [+] face to a limited-function [0] – [9], [+], [-], [x] face. A recessed tab located at the front of the ABLE calculator base allows the teacher to snap out one face and easily replace it with another to parallel the child’s acquisition of new math skills. All faces feature extra large, easy-to-read numerals on colorful yellow and blue backgrounds.

ABLE calculators and faces are available for use in conjunction with K-1 “Elementary Mathematics Concepts with Calculators”, a supplementary learning program for kindergarten/first grade students developed my math educators at the University of California ’s Lawrence Hall of Science. The ABLE calculator, when used as part of an integrated program, has been found effective in the teaching and learning of elementary math concepts – linking the concrete, visual, oral and abstract experiences of numerals, while constantly adapting to a child’s developing skills.

If you have additions to the above article please email: joerg@datamath.org.