The Acorn Plus 1 Expansion module

The Acorn Plus 1 Expansion module added an Analogue port, Printer port and two general purpose expansion sockets to the Acorn Electron. It slotted into place onto the rear expansion connector of the Electron and was fixed in place with two large fixing screws holding the Acorn Electron and Plus 1 together securely.

The Acorn Plus 1 Expansion module

Inside the Acorn Plus 1 Expansion module was an extra ROM socket which provided the extra functions required to control the Analogue and Printer ports and a handful of logic chips to hang it all together. Although the analogue port and printer port were not driven by the same chips as the BBC Micro's impleme