The Advanced Plus 3 is a small 7.5cm x 14.5cm x 1.5cm creme coloured interface which plugs into one of the expansion slots on the Acorn Electron Plus 1/AP1 or Rombox+ interface.

The AP3, like the Acorn Electron Plus 3 is an ADFS 1D00 interface. When connected to the machine, the memory locations &E00 to &1D00 of the Electron are used by this interface. When originally released, this feature meant many programs simply transferred from tape to disc would not work with it. However, thanks to the dedicated work of many Acorn Electron officiandoes over the years, there are currently several hundred professional games that have been recoded to run flawlessly on this interface. Only a few long programs, or programs which need to load in several parts, cannot be used with this interface.

The AP3 also boasts a spare 16K ROM socket which can be used to upgrade the interface with the DFS E00 chip, making the AP34.

The AP3 can be used with any Acorn disc drive that has its own power supply. If used with an 80 Track, double-sided disc drive, you have access to a storage capacity of 640K! All discs in our archives however are single-sided; this is to ensure compatiblity with the Acorn Plus 3, which was only fitted with an 80 Track, single-sided disc drive.

The AP3 came supplied with an ADFS Manual, identical to the Acorn Plus 3 one, and a disc containing the programs from the Introductory Cassette, some utilities and the Acornsoft games Snapper, Draughts and Reversi.

The AP3 was originally available by mail order from Pres for £61.10 (Bundled with an 80 Track, double-sided 3.5" disc drive it was £151.57). A second hand AP3 will usually sell on eBay for £25-£60.