Japan- 1975

"The author could see why people would want a specific number of digits in the display but why so many models? Suddenly the introduction of a scientific calculator the FX-101 brought a gleam in to the author's eye. Something new to explore and fiddle with. Still using the MicroPD series (this time a 979C) the unit dropped back to using a display decoder. It also had a ring-in, a chip designated T3184, listed as a rectifier although I doubt it is; the purpose is not known. One would suppose, to gain the extra chip space required for the additional logic the chip count had to be increased however, the display was still flouro an LD 8126. It had a fair compliment of Trig keys plus x to the y and pi or e to the x, etc."
Ray Mackay, Old Casio Calculators

Source: Ray Mackay

X-Number World of Calculators