A board designed to interface a computer to an Amateur radio transiever using a serial port and an audio card.

This Board uses screw terminals in order to make interfacing between radios fairly easy. All components are through hole, and the components (sans board) are about 25 dollars.

The main purpose of this board is for isolation of the electrical system of the computer from the radio (to prevent ground loops, hum, etc). This is done by two 600 ohm to 600 ohm audio transformers, and an optoisolator for the T/R switch. There is a current limiting resistor for the LEDs and opto IC, and another resistor as some radios require a certain amout of resistance in the PTT line. The 3 big vias are for a pin block to jumper between the resistor PTT and the strait PTT. This has been reworked into this size with some difficulty. The Author doesn't see any more places for parts to be rearanged in order for it to be any smaller. The Authors Amateur radio callsign can be seen on the board as well. Please note that I updated the holes for the jumper header as I designed them around the wrong part.