This is the new home of the MIDI Driver for older, USB-only Casio keyboards that do not work out of the box on Mac OS X. The driver is entirely based on sample code from Apple's SDK, and should work with many models of Casio keyboards. The project originated on Google Code, and you can still visit its old home at:
http://code.google.com/p/casiousbmididriver
The latest release supports Mac OS X 10.7 (Lion) to 10.10 (Yosemite) and is available here:
To install the driver, simply double-click on the installation package. It will install for all users on your machine.
You should then be able to plug your keyboard with a USB cable and power it up, it will show up in the Audio & MIDI Setup utility as "Casio USB Keyboard".
IMPORTANT NOTICE THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.