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YAESU FT817 CAT & DIGITAL MODES INTERFACE

This interface includes both the CAT and the PTT circuits,and it can be controlled from a single COM port ( link to the tutorial ).

The two diodes on the pins DTR and RTS of the serial port (pc side) allow to use either one of them to control the PTT.

The Yaesu FT817 provides voltage on the pin +13,8V of the connector ACC,even if it's switched off.

To preserve the internal battery of the radio,there is a switch on the CAT,so it can be switched off without pulling the ACC plug.

UPDATE MARCH 11,2009

I've received from Ivo I6IBE an interesting tip:

In the programs MixW,EasyPal,DigTrx there is an option to activate the PTT in the Yaesu radios via CAT.

That means that there would be no need to build the PTT circuit (the transistor 2N3904 and related components).

To enable this function in MixW,check the box shown in the following picture