* 6x8bit I/O port (using two [[8255 PPI chip]]s)
* Additional power-supply module (PSU)
== Technical ==
ROM is selected using an I/O port decoded with A15=1, A13=0. The ROM number is decoded using D3-D0 only, meaning a maximum of 7 ROMs can be used.
In addition more then one value can select the same ROM.
== Pictures ==