3 wires: Same pin-out as RC/Servos and other standard analog and some digital sensors. The beacons, buzzers and other low current actuators that needs GND/Vcc/Data use this connector too.
Julián,
how are you driving those modules? With PWM like servos or a different way? Are you just using for output the servo library if so?
I'm also interested in how data from sensor is read, do you use PWM with pulses between 1 and 2 ms here too?
Korman