DATAMATH CALCULATOR MUSEUM |
Texas Instruments TI-2550 (1st design)
Date of introduction: | January 10, 1974 | Display technology: | LED-stick |
New price: | $99.95, DM 298.00 | Display size: | 8 |
Size: | 6.5" x 3.2" x
1.8" 165 x 80 x 45 mm3 |
||
Weight: | 7.8 ounces, 220 grams | Serial No: | 2550149705 |
Batteries: | 3*AA NiCd or 4*AA Alkaline | Date of manufacture: | wk 29 year 1974 |
AC-Adapter: | AC9130 or AC9120 | Origin of manufacture: | USA |
Precision: | Integrated circuits: | TMS0601 | |
Memories: | 1 | ||
Program steps: | Courtesy of: | Joerg Woerner | |
Download manual: | (US: 1.8M Bytes) |
Roughly one
year [or later - continue here] after the introduction of the famous
TI-2500 alias Datamath
the engineers at Texas Instruments added a full memory onto the calculator chip.
Integrated into a housing similar to the wedge shape of the SR-11
it was named TI-2550.
Today
we know two different versions of the TI-2550:
The first calculators used a display module without magnification lenses
(actually a Bowmar Opto-stick), later TI-2550
calculators got the bubble lenses known from the TI-1200
and TI-30.
A close relative of the TI-2550 was sold through the American
department store Montgomery Ward. Compare the TI-2550 with the P200.
The same housing and a very similar keyboard was used by the TI-150.
Datamath™ is a trademark of Texas Instruments.
Recently we
received from a fellow engineer of a Dallas based company a parcel with some
calculator prototypes.
One of the surprises was a very early TI-2550 with a Date
code on the calculator chip indicating end of June 1974 as manufacturing
date. This prototype makes use of 9 single LED-modules known from the TI-2500 Version
3. Two explanations:
• The TI-2550 was introduced later in 1974 as we assumed. • This particular calculator was repaired and the first series used the single LED-modules instead the Bowmar Opto-stick. |
The TI-2550 is featured in the Texas Instruments
Deutschland GmbH leaflet
ER-1975 dated 1975.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, October 23, 2003. No reprints without written permission.