DATAMATH CALCULATOR MUSEUM |
Texas Instruments Business Edge
Together
with the FIA-10 the Business Edge established a new human
interface within the calculator line of Texas Instruments. Both supported
function keys with different meaning.
The Business Edge features five
pressure-sensitive areas on the LCD-screen and displays the actual function
under these squares. The remaining functionality could be compared with other
Financial calculators like the BA-35.
Dismantling
this Business Edge manufactured in January 1988 by
Inventec Corporation in Taiwan is a serious task because the printed circuit board (PCB) is
molded down to the housing with small pins. We opened the housing nevertheless
and traced down to a Toshiba T9728 single-chip calculator circuit connected with
a small flexible cable to the 5 touch keys.
Inspecting
the PCB of this Business Edge calculator brought our attention to a small mark reading IOST412-31D, we noticed similar marks already with other calculators manufactured by
Inventec Corporation and started compiling a list of the
PCB-Marks on calculators manufactured by OEMs for Texas Instruments.
The concept of variable function keys was later used on all
Graphing calculators like the TI-81.
A similar financial calculator was introduced with Personal Banker featuring Help Cards.
Compare the Business Edge with its close relative EC-5500 sold by Radio Shack.
Don't miss the APOTHECALC computer using a similarrsingle-chip calculator circuit for a completely different application.single-chip calculator circuit for a completely different application.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.