"klem kedidelhopper"

I've heard this noise before when using my inductive probe to find a
wire with tone on it and so I'm sure the sound is the data stream from
the alarm system keypad getting into the siren driver circuit.I tried
hanging different size caps across the mic input but none of them
reduced the noise.


** If both the lines involved REALLY are *equal level & anti-phase
balanced * AND twisted - there should be no such problem.

So I bet that is not the real case.



.... Phil