RIG interface

My ideas when designing this interfaces was:

• optoisolated interface - volatages between PC and rig can cause noise or damage
• USB interface - PC and laptops with serial ports is still possible to but choice is very limited. Laptops have only one serial port, is not enough for all interfaces (rig keying, CAT, rotator control...)
• maximal compatibility with radios - ICOM's CI-V is incompatible with Yaesu/Kenwood. Goal is to have minimal types of interfaces to cover all radios used in OK2M

1. CI-V interface for ICOM radios
2. USB to Kenwood CAT interface
3. USB to Yaesu CAT interface