flapjack is a program to flip the Belkin Flip KFM from Linux.
Right now, to use flapjack, you have to get the Linux kernel to present the Flip KVM as a hiddev device. This requires (as of kernel 2.6.20.4) a change to the blacklist in hiddev.c, adding the HID_QUIRK_HIDDEV to the product/vendor code 0x050d/0x3201.
By default, flapjack will scan the /dev directory to try to find the hiddev device file corresponding with the Belkin Flip vendor and product ID. If it doesn't find the file, then it will fail.
This can be overriden by either specifing a file, e.g.
$ flapjack -f /dev/usb/hiddev0 -c both
or by specifying an alternate devices directory to scan, e.g.
$ flapjack -F /mydevdri -c both
The Belking Flip KVM can flip only audio, only video, or both. These options are selected with the -c option, to which is supplied (surprisingly enough) "audio", "video" or "both".
See the info page for more information.