D80+K Floppy controller:

D80+K is a controller for 1 to 2 floppy disk drives for ZX Spectrum and compatible computers. During its development, emphasis was placed primarily on the maximum possible reduction of dimensions. It comes from the most popular, original interface of the same name from Slovak company named Didaktik Skalica Ltd, with which it is fully compatible. "+K" in the interface name indicates that this version also includes an interface for the Kempston joystick.


• Optional to connect 1 to 2 floppy drives 3.5"
• Fully compatible with the ZX Nucleon 512KB, ZX Spectrum 48KB, 128KB "toast rack" and 128K +2 Amstrad gray box (UK models), Didaktik Gama, M.
Interface is incompatible with the ZX Spectrum +2A, +2B and +3, these have non-standard signals ROMCS (2x) on the edge connector and incompatible ROM.
• Used original floppy disk controller GM82C765B or WD37C65B
• Two different versions of the system MDOS selectable by switches, 2.0B or 2.1B
• Integrated interface for Kempston joystick
• LED power-on indication (green LED) and MDOS system activation (red LED)
• The device is powered by the computer


Because the schematic is largely taken from the original interface, is directly compatible with these computers without any further modifications:
• ZX Nucleon 512KB (MDOS 2.1)
• ZX Spectrum 48KB (MDOS 2.0+2.1)
• ZX Spectrum 128KB "toast rack" with radiator to the right (MDOS 2.1)
• ZX Spectrum 128KB +2 Amstrad gray box (MDOS 2.1)
• Didaktik Gama, M (MDOS 2.0+2.1)
• Other clone with standard system bus connector and compatible Sinclair Basic ROM are theoretically compatible but not tested

ZX Spectrum 128KB +2A, +2B and +3: This computers is incompatible in terms of the ROMCS signal (25B), which is doubled with them. In addition, they also contain incompatible BASIC ROM. Therefore, the Beta Disk 128C interface can not be used with them!