Mic interface for RemAud

In a previous article I built a simple isolated audio interface to go between my radio and a PC for remote operation of the radio. This time I built an interface so that I could use the microphone from the radio on the remote PC 3 floors away.

I decided to use the mic from the HF rig as this would give the most accurate user experience. The user would simply pick up the microphone, press the PTT button and speak. The interface also has a USB to serial interface which allows the PTT to inform the computer that the user is in fact speaking.

And of course I designed a PCB for it. You can get it at Oshpark

Simply connect normal sound and usb cables from this interface to your PC and then plug your Yaesu dynamic mic into the other side. Tell RemAud to use the CTS line of the new USB-serial interface.

I've added an audio buffer with a 300hz filter to clean up the mic a little. This might not be needed and so you can simply omit most of those parts and jumper across from the junction of C4 to C6 but do leave C6 installed as there is DC power coming from your PC to power an electret mic.