AP117OSD: 1.RC PFV 2.show altitude, speed,direction etc 3.flight telemetry information onto your video image. AP117 OSD (On Screen Display) 1. Briefly introduceThe AP117 OSD overlays flight telemetry information onto your video image. The telemetry information displayed includes altitude, flight speed, flight direction, and home direction.The AP117 can be connected to the FY-21AP and FY-3ZT ...