is a series of electronic
graphing calculators produced by Hewlett-Packard
from 1990 until 2003. The calculators in this series were the HP-48S, HP-48SX, HP-48G, HP-48GX, and HP-48G+. The HP-48G II is not really a member of this series, but rather much more closely related to the HP-49G
. The 48SX and 48GX were expandable via special RAM
cards that could be purchased, whereas the rest were not.