It could be expanded with slots for three additional sound ROM cards.

The M3R was a cut-down model in 1U form factor that had similar sounds and its own line of ROM cards.

Instead, it uses so-called ROM cards, which are about the size of credit cards.

In place of diskettes, the Ultralite uses ROM cards, each slightly thicker than a credit card.

Only a handful of popular software programs are currently available on ROM cards, but more can be expected soon.

Another way the Ultralite deals with the data storage and memory challenges is the use of ROM cards.

A ROM card is the size of a double-thick plastic credit card, and it contains "read only" circuitry that holds the software code.

It is located in the hatch under the battery door, next to the ROM card.

Both cards fit into both slots, but the ROM card is larger.

Software can be bought running from ROM cards.