The connection between PC serial port and CI-V entry of Icom happens through an signal conversion interface you can purchase as Icom accessory ( CT-17 ) or equivalent as that proposed by the friend Lorenzo I2CYL, or, build following scheme.

Interface 1 to transistors

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Interface 2 - Use the IC MAX232 more efficentes in comparison to the transistors interface

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PTT Interface using a serial Com-port - signal RTS (not for IC-7000 )

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Interface for use with BKTkeyerCW plug-in