Keyboard Combiner

Version 1.0.0



Keyboard Combiner fixes a problem with the MacOS' handling of input from Apple Desktop Bus (ADB) and Universal Serial Bus (USB) devices, especially keyboards. Normally, your computer can recognize the button presses from only one keyboard or joystick at a time because pressing a button on one device causes it to replace the buttons on other ADB devices. Most of the time this is not a significant limitation but during game play, it can be very annoying. Imagine a two player game of Ambrosia's Mars Rising being played on a computer with an Apple Adjustable Keyboard (which is actually two different ADB keyboards). If one player is holding down a key on the keyboard part to move left and the other player presses a key on the keypad part to fire, the first player stops moving. A similar problem occurs when playing games with both a keyboard and a joystick. Keyboard Combiner allows your computer to recognize keyboard and button presses from all the devices connected to your computer at the same time.

System Requirements

Any Macintosh or Macintosh compatible computer running System 6.0.7 or better with an Apple Desktop Bus or Universal Serial Bus port. These systems range from the SE and to the latestPowerMac.


Name Kind Size
KeyboardCombiner.sit.bin Keyboard Combiner stuffed and in MacBinary format 102K
KeyboardCombiner.sit.hqx Keyboard Combiner stuffed and in BixHex format 139K


You should have received Keyboard Combiner in a package looking something like this:

As you can see, there are two versions of the Keyboard Combiner control panel. One is designed for computers running System 7.5 or earlier and the other is designed for computers running Mac OS 7.6 or later. To find out which version of system software you are running, go to the Finder and select "About this Computer..." from the Apple menu. Drag the appropriate version of Keyboard Combiner into your System folder. Restart your computer. When your computer restarts, the Keyboard Combiner icon will be displayed.

Getting Started

Note: Keyboard Combiner offers full balloon help support in System 7 or later.

When you open the Keyboard Combiner control panel, you should see something like this:

Combine Apple Desktop Bus devices

When this option is active, Keyboard Combiner keeps track of the buttons held down on all the ADB and USB devices so it can combine them together and prevent buttons on one device from replacing the buttons on the other devices.

Patch ChoiceStick Mark V driver

Keyboard Combiner cannot keep track of the buttons on the ChoiceStick without temporarily modifying the ChoiceStick driver. Uncheck this option if you do not have a ChoiceStick or you do not want Keyboard Combiner to improve the ChoiceStick's behavior. This option only takes effect when the "Combine Apple Desktop Bus devices" option is active.

Patch Flightstick Pro driver

Keyboard Combiner cannot keep track of the buttons on the Flightstick without temporarily modifying the Flightstick driver. Uncheck this option if you do not have a Flightstick or you do not want Keyboard Combiner to improve the Flightstick's behavior. This option only takes effect when the "Combine Apple Desktop Bus devices" option is active.

Differentiate left and right modifiers

When this option is active, your computer will treat the modifier keys (command, shift, option and control) on the left and right side of your keyboard as separate keys. You can use the extra modifier keys in games that can recognize them. Modifiers are useful in games because you can hold down as many of them as you want on the same keyboard where as only a limited number of other keys can be held down. This option only works with some keyboards and the left and right command keys are always treated as the same key.


When this button is pressed, a dialog similar to this will be displayed:

You can use this dialog to test the various features of Keyboard Combiner. Press buttons on your keyboard or Joystick and see what happens! You might have to setup your joystick's software to send key presses to Keyboard Combiner.

The "GetKeys View" shows the keys as a game or application would see them. Use this to observe the effect of turning the "Combine Apple Desktop Bus devices" option off and on.

The "Driver View" shows what keys Keyboard Combiner sees. This option is available only when the "Combine Apple Desktop Bus devices" option is on and Keyboard Combiner was loaded at startup. You can use the "Driver View" to find out if Keyboard Combiner can track the button presses of a joystick or other device. Notice that the squares get darker when you press the same key on different keyboards.


Keyboard Combiner may not work correctly with certain ADB devices. In this case, the device will simply remain unaffected by Keyboard Combiner options. We are always interested in hearing about the compatibility of particular devices, so please contact us.


Keyboard Combiner works with all Apple keyboards. It should also work with third party keyboards.


Keyboard Combiner does not affect joysticks that have special timing options. The drivers of these joysticks must be patched so that they tell Keyboard Combiner when a button is pressed. This has only been done for the ChoiceStick (driver version 2.01B2 ) and Flightstick (driver version 1.2.2 to 1.3.3) because these are the only joysticks that we have access to. The SideWinder has no special timing options and doesn't require a patch.

Other Devices

Keyboard Combiner should not affect devices that do not send key presses to the computer. Devices that do send key presses to the computer but were not listed above may or may not work with Keyboard Combiner.

Known Issues

Contacting Us

If you encounter a bug or problem with Keyboard Combiner or have any comments, please take the time to inform us. We are also interested in hearing about any features that you would like to see in future versions. You can get in touch with us through e-mail at