-// Format is "--serial=device,format,baud,direction" where
+// Format is "--protocol=medium,direction,hz,medium_options,..."
+//
+// protocol = { native, nmea, garmin, fgfs, rul, pve, etc. }
+// medium = { serial, socket, file, etc. }
+// direction = { in, out, bi }
+// hz = number of times to process channel per second (floating
+// point values are ok.
+//
+// Serial example "--nmea=serial,dir,hz,device,baud" where