Additionally to my new mono cam I ordered a Xagyl FW8x125 and had some troubles to get it to run. After a few mails with Dan I was able to fix the indi driver:
All commands have to be exactly 2 bytes long -> at the moment tty_write uses strlen(command)+1 (calculates to 3) and sends the string terminator to the wheel.
With the string terminator the wheel returns a timeout or a unknown command error if two commands are sent fast after each other.
With the removal of "+1" I was able to send correct commands to the wheel.
In the connect function the driver parses the firmware version. It seems like there is a mistake in the Xagyl manual as the wheel returns only the FW number without a preceding "FW". Removing the FW string in scanf (line 188) removes the problem and I am now able to connect to the wheel