DATAMATH CALCULATOR MUSEUM
Texas Instruments TI-55-II
|Date of introduction:||1981||Display technology:||LCD|
|New price:||$50.00 (SRP 1981)||Display size:||8 + 2|
|Size:|| 5.8" x 3.1" x 0.90"
147 x 79 x 23 mm3
|Weight:||3.7 ounces, 106 grams||Serial No:||210035|
|Batteries:||2*LR44||Date of manufacture:||wk 37 year 1981|
|AC-Adapter:||Origin of manufacture:||USA|
|Precision:||11||Integrated circuits:||CD4555, CD4556|
|Program steps:||56-0||Courtesy of:||Joerg Woerner|
|Download leaflet:||(US: 2.2 MByte)||Download manual:||(US-QR: 1.5 MByte)|
With the TI-55-II Texas Instruments added in 1981 a new calculator line to the existing slimline series. In you compare the slanted TI-55-II with a typical slimline calculator like the TI-53, you will notice some changes:
|• Larger display gives 8+2 digits instead 5+2
• 45 keys instead of 40 keys
• More space for the electronics
The display was not in one line with the keys but slanted
towards the user. Together with a perfect contrast and large digits the
calculator looked very professional. In practice the keyboard of all members of
the slanted scientific/financial calculators was terrible, either bouncing or
without any contact. Most users of the TI-55-II remember: "The -II
designation was evidently for the number of keystrokes that were recorded with
one button press". The calculators were usually replaced for free by Texas
Instruments with TI-55 III's which did not inherit
the bad genes of their forefathers.
Some very early calculators of the second generation were sold under the old designation TI-55 II with just a missing hyphen. View a very rare TI-55 II manufactured in Taiwan here.
The two-chip design of most slanted calculators allowed more features compared to the slimline series. The TI-55-II for example added a total of 8 memories to the basic functions. Find more information about the TP0456 calculator chips here. The TI-88 added a third microcontroller to this Master/Slave approach.
Known from the TI-53 and the original TI-55 is the simple programmability, here each memory could be converted to 7 program steps. A nice enhancement was a function to integrate with the Simpson-rule. If you are interested in the calculating accuracy of scientific calculators, don't miss the Calculator forensics.
One calculator in the TI-55-II series - the TI-54 - could manage arithmetic with complex numbers. Once again a "first" from Texas Instruments.
Don't miss an early prototype of the TI-55-II and the famous TI-88.
In Brazil the housing of the TI-55-II was changed to accommodate two AA-sized batteries instead the small coin shaped LR44 type. View this rare beauty here.
The US based company Jeppesen Sanderson developed a very
interesting navigation computer called prostar based on
Advanced LCD slide rule calculations with programming and statistics.
With 112 powerful functions for professional engineering, science, and math applications. Easy keyboard programmability; including function evaluation and integration features, saves time on repetitive problems. Also the most needed statistical functions for better data analysis. Use up to 8 memories. Built-in conversion functions for fast transition between various measurement systems. Plus: roots, powers, reciprocals, log, trig and hyperbolic functions. Enter data in standard, scientific, or engineering formats.
© Texas Instruments, 1981
If you have additions to the above article please email: email@example.com.
© Joerg Woerner, December 5, 2001. No reprints without written permission.