If you use a NXP SC18IM700 Serial to I2C chip it directly interfaces to the Si570 or the PIC socket . The serial interface can be run at various baud rates and can easily be opto isolated from the PC on a RS232 or USB converter. The demo kit from NXP OM6272 is fully built with RS232 in and power from USB on PC It also works with most [all that I have tried] USB to 232 converters, - again simple to opto-isolate the USB to 232 and run demo kit from same supply as Softrock 5V [3.3v reg on the demo] or 12V with resistor.
PC can do freq calcs and register value generation very easily. Not presently sure how to capture CAT from Kenwood, but probably could loop through or capture from another RS232/USB port. CAT from ICOM would be another option to be included. Actually an interface from Ham Radio Deluxe might be easier http://groups.yahoo.com/group/ham-radio-deluxe/ <http://groups.yahoo.com/group/ham-radio-deluxe/> or http://forums.ham-radio.ch/ <http://forums.ham-radio.ch/> Dick Faust K9ivb
