Additional Pictures 


The TP0456 microcomputer based Master/Slave architecture found in the TI-55-II calculator.
The CD4556 forms the Master, the smaller CD4555 the Slave.

From left to the right three different TI-55-II and TI-55-III printed circuit boards (PCB's):

TI-55-II manufactured in the year 1981 in US. 
Famous for the bouncing keyboard introduced with the slimline calculators.


TI-55-II resp. TI-55-III manufactured in the year 1985 in Taiwan. 
Uses two PCB's, one for the keyboard.


TI-55-III manufactured in the year 1986 either in US or Italy. 
Uses far-east keyboard technology with conductive rubber together 
with contact fingers on a flexible PCB.

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, October 11, 2002. No reprints without written permission.