Texas Instruments TI-66

The TI-66 Programmable, introduced in May 1983, was a landscape-oriented scientific calculator designed as a successor to the TI-58C. It featured a 14-segment LCD display, 512 program steps, and 64 memory registers, making it a powerful tool for engineers and scientists. Unlike its predecessors, the TI-66 was manufactured by Toshiba, incorporating a T6875 microcontroller and TC5514A RAM chip. It supported conditional execution, subroutines, and indirect addressing, offering advanced programmability similar to the TI-59, but in a more compact form. The calculator was powered by two LR44 button-cell batteries and could connect to the PC-200 printer, expanding its functionality. Its design was likely inspired by Hewlett-Packard’s Voyager series, marking a shift in TI’s calculator aesthetics.

My dad had this calculator from when he used to work for Texas Instruments from 1981 to 1996.