Pls let me know the cheapest way to make an intercom to speak between 1st floor to 3rd floor without a phone line.

I would like to make a home intercom to communicate with my brother who resides in the 1st floor & myself in the 3rd floor in the same apartment.  It is costing us more to contact via our mobiles each & every time by our house members.  So, I have 2 old telephones with me & want to know the method to connect the same to be used as an intercom.

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I actually built such a device, a few years back, an intercom that uses POTS (plain ol' telephone service) phones.  As others have pointed out,  the tricky part is generating  the (approximately 50V AC) "ring" signal.  As for connecting the two phones together, that's the easy part.  Just connect both in parallel, with a 6V DC power supply.  I should draw a diagram of this.

BTW, everything I've written so far assumes you have some way of running a wire (a pair actually) between the 1st and 3rd floor.

kelseymh7 years ago
Buy a pair of really cheap walki talkies at a toy store or a thrift store.  Mount them on the wall with a bracket or double-sided tape.
 That's what I was going to say, too.
caarntedd7 years ago
Kiteman7 years ago
You could try walking downstairs...
This would probably work:

You'll need to find a way to make a ringer though, as this does not include a ringer circuit. I'd recommend a wireless doorbell if you don't want to build anything else.