Is it possible to work with switches Niko
type 170-05000
and can anyone explain the difference between NO / NG
thx
Sven
Yes, they are compatible with the pushbutton module.
NO: normally open contact.
NG: normally closed contact
is it possible to have a controle led whith the new niko buttons ?
they work on 230 V how we must make the cabling 
You should remove the 230V indicator lamp and replace it by the supplied leds.