Features:
Brand: 915MHz
Antenna connectors: RP-SMA connector
Output Power: 100mW (20dBm), adjustable
between 1-20dBm
Sensitivity: -117dBm sensitivity
Interface: Standard TTL UART
Connection status: LED indicators Demonstrated
range of several kilometers with a small omni antenna
Can be used with a bi-directional amplifier for even more range
Open source firmware
AT commands for radio configuration
RT commands for remote radio configuration
Adaptive flow control when used with APM
Based on the Hope RF HM-TRP radio module,
featuring an SiLabs Si1000 RF microcontroller.

It is open source product that do not have introduction inside, please kindly search "3DR radio" in google or youtube then you wil find many wiki and videos such as these:
http://www.geeetech.com/wiki/index.php/3DR_Radio_Telemetry
and this:
https://www.youtube.com/watch?v=W4E-4lvPbqc

• Support OTG of Android Cellphones,and computer OTG. Antenna is 5.8G level ,not the cheap 2.4G level (whose range is very small and material is very cheap) like others.

Support OTG of Android Cellphones,and computer OTG. Antenna is 5.8G level ,not the cheap 2.4G level (whose range is very small and material is very cheap) like others.LPZ RC Shop