Cartridge Port Expanders

by Dick Estel

When Commodore Business Machines released the original Commodore 64, they wisely included a
cartridge port. Originally this slot was primarily used for game cartridges, but programmers soon came
up with numerous other devices to plug into that spot to improve the capability of the machines.

One of the first was the Fastload by Epyx, which not only improved the notoriously slow loading rate of
programs, but also gave users a built-in DOS wedge, eliminating the need to load it as a separate
program. RAM expanders (REU's) from CBM and other utility cartridges followed, and soon a
Commodore user could find himself with three or more items in regular use, all vying for the single
cartridge port.

Realizing that removing and inserting different cartridges was a lot of trouble, as well as a source of
wear on both the computer and the plug-in device, Aprotek and other companies soon came to the
rescue with cartridge port expanders. These devices plug into the cartridge port and have several slots
to allow several cartridges to be plugged in at once (usually three or four). They have switches to allow
a specific cartridge to be on or off, and even permit the use of two or more cartridges at once. 

This was particularly useful for combining the services of a utility cartridge with a REU (attempting to
use two or more utility cartridges together usually produces conflicts). 

I have the Aprotek 4-slot unit, and find that the REU and the Super Snapshot function together in
perfect harmony. The only serious drawback is that the expansion slots require the cartridge to be
inserted vertically. This is not a problem with most game and utility cartridges, which usually measure
about 3 1/4 by 2 3/4 inches. However, the REU is a much larger device (CBM's unit is 6 1/4 by 5 1/2
inches), and is a bit wobbly this way. Even so, barring earthquakes and sudden hard bumps to the
computer, the REU seems to "stand up" to this configuration with no problem.

Another problem affects these units in some conditions. I had experienced some problems with my
Pacman cartridge not working, and asked Del Contreras if he thought it was due to wear on the slots.
He pointed me toward the solution--some programs demand to be in the first or second slot. I moved
Pacman to the number one position and it worked fine.

Recently there have been solutions to the other problems mentioned. Not surprisingly, they come from
Creative Micro Designs. With no other expansion units still in production, about two years ago CMD
brought out the EX3, priced at $34 and the EX2+1 at $39. The first is similar to earlier devices, with
three vertical slots. But the EX2+1 has two vertical and one horizontal slot, the latter at the end,
allowing the larger Commodore REU to plug in and lie flat. CMD also produces their own variation on
the RAM expansion units, the CMD 1750 and 1750XL (reviewed in our October-November 1997
issue). Both are the size of a standard game or utility cartridge, allowing stable vertical installation.

Other than the CMD units, the only way you can obtain a cartridge port expander is to find one on the
used equipment market. If you use a utility cartridge and REU extensively, or find yourself pulling some
of your old game cartridges in and out, it's worth investing in one of these useful devices.

From "The Interface," newsletter of Fresno Commodore User Group