Fig. 1 - Texas Instruments TI 3500 desktop calculator Fig. 2 - TI 3500 calculator uses 11-digits multiplexed Burroughs Panaplex II display and Texas Instruments LSI Single-Chip TMS0106 made in N-MOS technology Fig. 3 - A printed circuit board of the TI 3500 calculator is single sided PCB TI 3500 calculator Texas Instruments TI 3500 was introduced in 1972 in the USA as business 10-digits desktop calculator with four basic operations (addition, subtraction and multiplication, division), chain and constant. It has one memory. The calculator works either in floating mode or in fixed mode with 2- or 4-digit's precision. The TI 3500 is powered from 220V AC line. An introductory price in 1972 was $99.95.