Guess need to ask 
   
  1. is this a mission critical type sensing?
  2. how reliable do you want it to be
  

Ben Wheare <piclist@bwgames.net> wrote:
  That was one of my thoughts, but won't the voltage drop over such a long
cable make such a solution impracticable?

On 24/10/2007, Harold Hallikainen wrote:
>
> How about a "wall wart" transformer powered by the AC you are watching.
> The DC output drives one pair of the cable directly. At the far end, a
> resistor and LED indicates power is present. An LED based opto coupler
> could be substituted for the LED to drive a PIC.
>
> Harold
>
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