ROM gate switch-over for Atari ST

Many games, utilities and other application software for the Atari ST computer are supplied as ROM / EPROM modules ('cartridges') of which, unfortunately, only one at a time can be connected to the computer. The circuit described here over comes this undoubted short coming of an otherwise excellent computer. It allows up to five ROMlEPROM modules to be connected at the same time, and to be selected by software.