A DIGITAL MODES FULLY ISOLATING COMPUTER INTERFACE

            Nothing here that’s Rocket science, but if you want to make sure your radio doesn’t upset your computer then this is a simple way to achieve it.

Transformers for sound isolation and opto-isolators for control.

The PCB is designed to fit into a Farnell box  318-3567. You will be able to plug the box directly into the serial port, then make up two 3,5mm leads with phono plugs each end to connect the computer MIC and EAR jacks to the corresponding ones on the board.

The Radio connector is a 8 pin round DIN socket wired mostly   to a Raynet standard called CAIRO. The audio paths are isolated from the PTT and KEY lines so you can easily interface the board to any radio, even a handset! Multi-turn cermet pots are used to set levels.

DIN socket                  RS 453-117                 1.348 EACH   

Transformer                  RS 210-6223   X2       2.55 EACH      OEP1200

Opto isolator                RS 453-1205               0.95 EACH      ISOCOM ISP825X

3.5MM Jack socket     RS 476-328  X  2        0.696 EACH   

Box                              Farnell 318-3567