Thanks Alain,

Good idea. But Switzerland is not like other countries: a DS2405 costs around €2.- as a 10F200 only €0,80...

Furthemore, I'll have to build some circuitry to make the Input a Schmitt trigger (wich I won't have to do with the PIC).

Thank you Dave. I was assuming the master PIC "interrogating" the slaves one would be the simplest way of doing.