Easy Digi board, surface mount, good for APRS, and other PC to Radio interfaces

Description

This is an Easy Digi board, and it is improved a great deal over other boards of this type. It measures .98" wide by 2.38 inches long. Ideal for fitting into project cases along other boards.  The  transformers are all 600:600 and used for audio isolation.  The board does not handle any power, so the surface mount parts were a good choice, as they don't wear out . It is basically all audio levels, which are very lower power.  The PTT circuit is used to key a radio, through the use of a computer signal. The board has many uses.  Note that the transformers look like two different colors, it was the lighting, they are both the same.  The boards are tested before shipping.  This is the best of this type of board, it is arranged the way it is used. Connections are the the edges of the board, one side is where the audio goes in, and the other is where it comes out. PTT is handled at the end with the Opto coupler, it is usually controlled by a GPIO pin on a Raspberry Pi. I have used the board this way, by using a FE=Pi sound board that plugs right into the top of the Raspberry Pi. I solder a wire to the buss pin for GPIO.  For APRS I use a Kenwood TM-281 that I modified to have a data port from a plan I found on the internet. It was easy to do, and keeps the volume control out of the circuit for audio, so you don't hear the radio making all that noise, and it works perfectly. The audio levels are controlled on the Raspberry pi Linux install, along with audio controls that help you get your volume to the correct level. The software I used is Direwolf,  it is the most power TNC software you can get, and it is free to download and install. There is a Facebook page for it, so questions can get answered there.  I use Audacity to adjust audio levels on my Raspberry pi.