How can make a system which have two circuit. And one is place at ground floor and another is in roof. We send voice (like call) one from other by pushing a switch and vice versa. It may be wired system. I want to make this system. Can you please help me?
closed as too broad by Transistor, brhans, Chris Stratton, Scott Seidman, Dave Tweed♦ Nov 26 '18 at 17:54
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Sounds like you need something like this simple intercom. There are plenty of similar circuits about if you look. If this looks too complex, then buy something off eBay!