HP 48g Graphing Calculator - Manual (Page 403)

Expanding User Memory with Plug-In RAM
Cards
You can extend built-in HP 48GX user memory by installing a RAM
card into Card Slot 1 and merging its memory with user memory.
{The HP 48G model has no plug-in card slots.)
Each RAM card contains a battery that preserves its contents while
the calculator is turned off and after you’ve properly removed the card
from the calculator. (The calculator batteries power the RAM card
only while the calculator is turned on.)
You set up a RAM card as one of two types of memory—each with its
own benefits. You can change between the two types—but you can’t
use one card as both types at the same time.
■ Merged user memory. The part of user memory that’s contained
in a RAM card—the card’s memory is merged with built-in user
memory. This lets you expand the amount of user memory for
creating variables and directories, and for putting objects on the
stack.
■ Free port memory. RAM memory that’s independent of user
memory—in built-in memory (in port 0) or in a RAM card (in
ports 1 through 32). This lets you back up individual objects or
entire directories, much as you’d back up computer files to a disk,
then store it in a safe place. You can also use it to transfer data to
another HP 48 by installing it and copying the objects there. See
“Backing Up Data” on page 28-3.
28
in a port:
Enter the port number and press
LIBRARY)
in level 1 indicates the type of memory:
" R O M "
ROM in an application card.
" S Y S R f T r T ’
Merged user memory in a RAM card.
number Free port memory in a RAM card.
b - i R S .
The result
Libraries, Ports and Piug-ln Cards 28-15