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For single radio installs eliminate the J45.If you plan on using traditional FSK or computer generated CW then this second keyed line will be useful.Remove SW1 and replace it with a simple STSP switch between the Dual color LED and J1.Replace the two solid state relays with optical isolator such as the 4N25.Build a different CAT 5 cable for each radio and switching radios is as easy as plugging a different CAT 5 cable into the I/O.
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#Optical isolator 4n25 manual
Here is a copy of the manual ( KK7UQ Interface manual) it includes a complete explanation of the circuit and the interesting radio to interface scheme he uses. Unfortunately the kit is no longer available. It was easy to build and fit very nicely into an Altoids box. The Gold Standard (KK7UQ Interface Model II):Ī number of years ago Clinton Hurd (KK7UQ) designed and sold this interface as a kit. In this article: KK7UQ the Gold standard, Why it is a good design, Changes, Simplified Schematic, Bells and Whistles This is part three of the series on Digital Communications.