I recently installed an Electronics International FP-5L Fuel Flow gage. I ran the serial data lines to a panel mounted 1/8" stereo plug on the panel. I connected it to my iFly-700 using the USB adapter. I removed the DB-9 connector and replaced it with the stereo plug. I got everything to work fine, and the EI instrument was displaying MPG and fuel at destination just fine. But I noticed noise on certain COM channels on my King KX-155. Disconnecting the USB connector from the iFly causes the noise to stop. The stereo plug is grounded at the panel. Should I try floating this ground? Any suggestions?
Rich Harrison