HP-48
The HP-48 is a series of electronic graphing calculators, produced by Hewlett-Packard from 1990 until 2003, that use Reverse Polish notation. The calculators in this series were the HP-48S, HP-48SX, HP-48G, HP-48GX, and HP-48G+, the G models being extended, improved versions of the S models.
The HP-48G II is not really a member of the series, but rather much more closely related to the HP-49G and HP-49G+. The 48SX and 48GX were expandable via special RAM (memory expansion) and ROM (software applications) cards that could be purchased.
References
- Byrne, Diana K., et al. (1994). An Advanced Scientific Graphing Calculator. Hewlett-Packard Journal, August 1994, pp.6–22.
