phone problem

When I'm talking on the phone with a good clear, strong signal and my wife picks up another extension the person I'm talking to says the volume drops by 50%. When my wife hangs up then the problem disappears. Does this mean there is a voltage drop on the line when the other extension is picked up and how do I check the line voltage? I have a vom and know how to use it if that may be the problem. What is the line voltage supposed to be when talking? I think it is much less than the ringing voltage..........any help will be appreciated.........thanks in advance...........clark

 

crappy , phone or phones the circuitry within the phone should control it

get a better quality phone