Pierre, typically a relay output from a radio GROUNDS on transmit.
With a tiny bit of circuitry you could turn that into a +5V or any other signal that you need.
I have elsewhere showed how to create an optically isolated output to control such a linear
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However, I think I have seen that newer Sbitx may come with this.??
I don't know if there is enough room in the zbitx?
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The important thing is to use DIGITAL inputs to control such a circuit, never the analog TX lines -- exposes too much risk of RF getting places it shouldn't.
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Once you have ANY kind of output that is appropriately safely isolated, a little bit of circuitry and you can control just about anything.? ?
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Hope this is of SOME help
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Gordon KX4Z
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