Interlock controller is based on KK1L switch with some of design modifications to consider available parts here locally. It uses same logic gates and relay driver  transistors in smd packs. I have kept BCD logic out of the main board to make future design provisions. Also plan to use low cost relay boards readily available at market place for intermediate switching and driving higher current required for matrix of modular switches. (each radio path may require upto 4 modular switches to reach selected antenna each with three relays to be be driver)

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