This is the most common type of connection for RC transmitters, with Spectrum, JR, Walkera, Hitech, and many other brands of RC Transmitters using this type of jack to output PPM signals.
For the Dragon Link Transmitter to work, it needs two things:
1. PPM input from your RC Transmitter: This is the phono plug part of the cable pictured to the left
2: 5 - 18 volts of Power: The two wires with the RED plastic connector are for feeding power to the Dragon Link Transmitter. Unfortunately the JR / DSC type port does NOT output any power, only PPM signal. That makes this the most cumbersome of all the connection methods as you need to have a small external LIPO to power the Dragon Link Transmitter with. You can use LIPO from a 2 to 4 CELLS, 1000 mA or larger to power your Dragon Link Transmitter, this will power your Dragon Link Transmitter for many hours. Get a small enough LIPO so that it is not heavy and cumbersome to mount to the back of your RC transmitter along with your Dragon Link. Again I like mounting the battery with Velcro as well, it fast, easy, and can be removed in seconds if you want. If your LIPO has the same type connector to fit the plastic RED connector, simply plug it in and it will work. If the connector is different, you can splice it, or cut it off, and install any kind of connector you like best.
NOTE: If you do not want to use an external LIPO, most RC transmitters have enough internal battery capacity to power the Dragon Link V3 system for several hours. You can cut the RED connector off the cable, add a switch, and solder it directly to internal power in your RC transmitter. If you choose this method, make sure you know what you are doing as you can damage your RC transmitter if done incorrectly. There are some good videos on YouTube on how to do this on different types of RC transmitters.
CONFIRM YOU HAVE POWER: When you supply 5 - 18 volt power to your Dragon Link Transmitter, you will hear a tone and get some LED indications on the Top of the Dragon Link Transmitter.
WARNING: You MUST disconnect power to the Dragon Link Transmitter when you are not flying, as the unit will continue to transmit and run down your battery regardless if your RC transmitter is turned off.
STRONGLY SUGGESTED: Set the Voltage Alarm on your Dragon Link transmitter so that it sounds an alarm when your LIPO reaches 30 % of capacity. It would be horrible to be flying and have your Dragon Link battery go dead, and have the Dragon Link Transmitter shut down with the plane in flight. This alarm can be set very quickly and easily by clicking the " ALARMS " tab at the top of the Dragon Link Configuration software, and setting the " Low TX Voltage alarm for the appropriate level. See picture of this screen to the left.
CONFIRM PPM SIGNAL BEING SUPPLIED TO DRAGON LINK.
When PPM is supplied to the Dragon Link Transmitter, the LED on the top will turn GREEN, this means Dragon Link is receiving the signal and stick positions from your RC transmitter. If the LED is RED, there is NO PPM signal being supplied by the RC transmitter, and you must find the problem, the system will NOT operate without PPM input and a GREEN LED indication.
NOTE: Most Spectrum and JR transmitters must be left powered OFF for the DSC port to work, DSC is activated the moment your plug the Phono Plug into DSC port. If you turn the power switch ON these radios, many times the DSC will not work correctly.
NOTE: Most of the time, the DSC port will work perfectly without changing settings. If you have a GREEN LED indicating good PPM, and still get non moving servos with a fully bound and operational system, many times the DSC port is in the wrong mode in the RC transmitters computer menu. You can try different modes and settings, it will not hurt anything.