All Amiga models have two ports running along the back of the machine that allow plugging in a mouse and a joystick (although the joystick can be a joypad or a footpedal device). There is a large number of games that support two player gameplay and they require a second controller to be plugged in. Since the Amiga has just two ports, a mouse port and a joystick port, the second joystick would be plugged into the mouse port by first removing the mouse. Unfortunately, hot-removing the mouse whilst the machine is running may cause damage to the CIA device let alone being an inconvenience since the mouse and second joystick would have to be hotswapped every time to switch between the mouse and the second player joystick.

To work around that issue, there are a number of mouse and joystick switchers available for the Amiga but they all have flaws that are sometimes a showstopper. Most switchers are external devices and connect to the Amiga with a short wire running to the mouse port and a dangling device into which the mouse and second joystick is plugged in to. Some switchers are not automatic and require a switch to be flipped in order to change between the mouse and the joystick; others are automatic and just require a button press on either mouse or second joystick to be pressed in order to switch.

One mouse and joystick switcher is the KMTech autoswitcher created by Kevin Mount that seems to be a good choice: a Roboswitch device, for instance, has the drawback that with some joysticks, the Roboswitch keeps pressing one of the joystick devices which produces some issues in Workbench.

Nevertheless, the KMTech autoswitcher is a bare bones device that is sold just as a PCB without a case and seems to be quite a bulky device. The KMTech autoswitcher PCB is perfect though to be integrated as part of an Amiga Blackbox case.

Fortunately, Amiga 1200 motherboards have a particularity where the placement of the mouse port varies just a little between motherboard revisions but all revisions have a 10 pin header socket marked CN1A from which leads for the mouse port are pulled. 1D4 motherboards have a ribbon cable running from the CN1A port to a mouse port connector and are easy to modify. On the other hand, the 1D1 motherboards are full sized and instead of using a ribbon cable to connect the mouse port, the 1D1 motherboards have the socket soldered onto the extended motherboard PCB.

However, looking at the 1D1 motherboard, the CN1A connector is still there and can be harnessed by soldering IDC pins. The first step is to use ChipQuik, copper wick and a vacuum gun to clean CN1A socket of solder and open it up for the IDC pins.

The procedure can be performed in-place without dismantling the Amiga and all the addons since the Blackbox conveniently leaves the CN1A socket free - only the power supply has to be dismantled. After the socket is cleaned and freed up, the next step is to drill two socket holes into the back of the Blackbox using a Dremel.

Using some black paint, the eventual slips of the Dremel can be covered up nicely for the perfect finishing touch.

Now, with a ribbon cable and socket lifted from a spare 1D4 motherboard, the CN1A connector can be coupled with the input of the KMTech autoswitcher.

The power supply fits nicely in parallel with the KMTech autoswitcher since it rests just on a nook and does not even make contact with the autoswitcher. Of course, one pitfall of this mount is that the LEDs will be covered however, the functionality of the KMTech is simple enough and the LEDs are not really needed as indicators.

The KMTech PCB is perfect for being fitted inside the case - the autoswitcher has the habit of dangling off the back of the Blackbox case and sometimes even makes poor contact with the exterior mouse port and by fitting the switcher inside the case that problem is eliminated.

One important note is that the mouse port should not be used whilst the KMTech is in use - although it probably can. Given a 1D4 motherboard with a ribbon cable socket, the KMTech itself could have been modified to lift the mouse port and drive it to the hole in the Blackbox case. However, this mount is designed to require the least amount of modifications to the hardware by leaving the mouse port on the motherboard the way it is.