Home Automation - Telephone to Intercom System

I'm wondering if there is any way to connect my vintage rotary telephone to my existing Nutone intercom system installed in 1997. There are 3 wires (orange, green, blue) in the intercom and when I tried to connect then to the telephone randomly I got some signal. Any idea on how to go about this properly?

Can you connect any telephone to that Intercom system? That sounds like an apples and oranges situation, I can't imagine most intercoms having any standard phone instrument compatibility.

Well a telephone is basically just a mic + speaker with two lines, there must be some way to make this work?

Well, actually it's a bit more than that. Also, the mic in that old telephone is a carbon mike, and it requires power to create audio.

I'm not saying there isn't any way, but this effort will require an interface circuit to do the job, and sure doesn't seem worth it to me...

Most Intercoms use the speaker as a mike, they're a very different breed than a telephone instrument.

Telephones require an audio signal path, which you already have from the Nutone.

They require -48v DC voltage (called "battery"). They need 25-cycle AC power to make the phone ring. Nutone can't deliver the latter two.

Also, telephones are generally 300- to 600-ohm devices. When I last checked, Nutone uses 45-ohm speakers which double as mics. This mismatch will cause audio levels to be very low.

You might be able to make it work with a device like the DoorBell Fon (http://www.doorbellfon.com/product%20main/productsmain.htm), but $200 seems like a lot of money for the novelty of using an old phone.

I see... thanks a lot for the information everyone