This is the FRsky D4R-ii Receiver which is a 4 channel (PWM) or 8 channel (CPPM)  2.4Ghz receiver which uses the FRsky ACCST technology (Advanced Continuous Channel Shifting Technology) to ensure rock solid signal to your aircraft.  If you need to use more than 4 Channels with this receiver you simply need to add a jumper (included) across CH3 and CH4 and the FRsky D4R-II receiver will output an 8 CH CPPM signal over the CH1 connection, and the RSSI over CH 2.

Note: The firmware on the D4R receiver is not compatible with the EU LBT firmware. If you would like to use this receiver with the Taranis X9D+ Radio, you will have to upload the international firmware on both the Taranis and receiver. 

D4R-II Specifications

D4R-II Compatibility

• Compatible with FrSky two-way telemetry TX modules: DFT, DJT, DHT, DHT-U.

Resources

• D4R-II Manual and Firmware Updates