Supply - Power supply connector
1: + 7-25 V
2: ground

Out - RDS output
1: output
2: ground

LPT - PC port interface
1: SDA (serial data)
2: SCL (serial clock)
3: ground

Level - Output RDS signal level adjust

The communication interface meets the IIC serial synchronous bus standard with the clock rate limited to 600 Hz. So the unit can be also controlled from almost any microcontroller. 
The PC control software emulates the IIC bus on the LPT or COM port. 
It's prefered to use LPT (parallel port) rather that serial COM. You must be logged under administrator laws in Windows to access parallel port. Serial port can be accessed in all cases. 
Some low cost USB-to-COM adapters don't handle all port pins required by the unit. You may use Port Access TEST built in the control application to check it. 
The RDS unit must be powered when sending any data. 
We do not supply any cables or adapters with this unit. 



Mono transmitter with audio or MPX input connector (may used with stereo encoder plugged to this input)
Audio/MPX and RDS signal must be mixed together and pluged to the transmitter input. There exist many ways to do this. You may use simple schematics provided below. The resistor values are chosen approximately, but these values might be right.
2 Resistor Pic



Stereo transmitter with audio left and audio right connectors and no more inputs
An encroachment to the transmitter is necassary here. Find a varicap (capacitive diode) in oscillator and connect the RDS input connector by the following diagram. Then fix the connector in front panel of the transmitter.
Resistor / Cap Pic