The Texas Instruments TI-92 calculator
is an unusual calculator, quite large and with a QWERTY
keyboard. A programmable calculator, it comes with a computer algebra
system (CAS), and was one of the first calculators to offer 3D graphing. Unfortunately, the TI-92 was not allowed on most standardized tests due mostly to its QWERTY keyboard. Its larger size was also rather cumbersome compared to other graphing calculators. In response to these concerns, Texas Instruments introduced the TI-89
which is functionally almost identical to the TI-92, but smaller and without the QWERTY keyboard.