Simple joystick interfaces are a thing of the past... the "Dual Joystick Interface "KEMPSTON_MAX 2" interface offers more:

Key Features:

8 different joystick modes
Kempston joystick interface mode
Sinclair joystick interface mode
Protek joystick interface mode
also works with Amiga/Atari ST mouse
QAOP M-key emulation
QAOP spacebar emulation
Magic key (reset, joystick mode)
Full passthrough - you can connect any device that uses the ZX Edge port.
Joystick mode/activity LEDs
built on XC95144XL CPLD and Atmel AVR
Case with rubber stands, made with laser cutting
jumper-free configurable modes of joystick ports
12V/9V/5V status LEDs

A great new product for the ZX Spectrum, compatible with 16k, 48k, 128k, +2, +2A/B and +3.

Functions:

JOYSTICK PORTS: as already mentioned, the joystick ports can work in 8 modes. To switch between the modes, press the magic button. Each press switches to the next mode.

MODE 1 : Joystick Port A = Kempston Interface Port 31 (standard)

Joystick Port B = Kempston Port 55 with a joystick connected or Kempston Mouse with an Amiga mouse connected.

MODE 2 : Joystick Port A = Kempston Port 31 (standard)

Joystick Port B = Kempston Port 95 with a joystick connected or Kempston Mouse with an ATARI ST mouse connected.

MODE 3: Joystick Port A = Sinclair 1 (6,7,8,9,0)

Joystick Port B = Sinclair 2 (1,2,3,4,5) (no function when mouse is connected)

MODE 4: Joystick Port A = Sinclair 2 (1,2,3,4,5) (no function when mouse is connected)

Joystick Port B = Sinclair 1 (6,7,8,9,0)

MODE 5: Joystick Port A = Fuller Port 127

Joystick Port B = Kempston Port 55 (no function when mouse is connected)

MODE 6: Joystick Port A = PROTEK / CURSOR (5,8,6,7,0)

Joystick Port B = Kempston Port 55 (no function when mouse is connected)

MODE 7: Joystick Port A = QAOP / Space

Joystick Port B = Kempston Port 95 (no function when mouse is connected) Mouse)

MODE 8: Joystick Port A = QZIP / Space (=Hungry Horace Mode)

Joystick Port B = Kempston Port 95 (no function when mouse is connected)

Dual Joystick/Mouse-Interface "KEMPSTON_MAX 2" compatible with ZX Spectrum