This device is developed for UAV signal transmission system with 1 analog video and 1 TTL level signal. It is safe and reliable, stable in performance, light in weight and cost-effective. It can be customized on demand. The wavelength of the optical fiber at the ground / air / ground+air end is 1550nm, The interface is defined as: RX/TX/AV/VCC/GND, RX is connected to the CRSFTX of the remote control receiver TX is connected to the CRSFRX of the remote control receiver. AV output to display screen or VTX AV signal input port VCC supply voltage is 5.5V~26V Power supply: 5.5V-26V: (2S-6S battery) Power consumption: less than or equal to 5 W Communication interface: MX-SH1.0mm-5P: CRSF interface/CVBS video port Optical fiber interface: FC communication distance: maximum 20KM Color: As shown Material: PC Specification: ground / air Package Contents: 1 x TTL Optical Transceiver Module(The circuit board printing is slightly different, which does not affect the use) Specification: ground+air Package Contents: 2 x TTL Optical Transceiver Module(The circuit board printing is slightly different, which does not affect the use) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.