I am using a Arduino to Transmit over radio.
i have completed most parts but this bit confuses me, I know its simple but just confuses me,
The Books says :Put this pin low (less than 0.66 Vdc) to key transmitter and enable external mic audio path. This path is pulled low via a diode when front panel mic PTT is pulled low to allow sensing of mic PTT by accessory. This pin pulled high to 3.3 Vdc via 3.3k ohms
how do I use a Arduino UNO to do this???????