Door intercom

[skystorm]

Hi all

Got a call today about an intercom systems for a old man , ITS GDX phone he had one in the corridor ,which someone move to the sitting room and another one installed in he's bed room, Had a look at it only 4 wires o/w o, b/w, b , The problem is it does not buzz at all . But you need to use all four wires for it to work ?:|

any help would be great full thanks

 

[sparkytim]

Normally 5 wire system.

Sure you have not lost a core?

 

[skystorm]

Thanks sparkytim sorry only 4 wire