Author Options:

Making a Telephone Function Without a Phone Line? Answered

I have an old telephone desk set with a DTMF keypad. I was wondering if there was a way to some how get it to function without hooking it up to a telephone line, not to call people, but to make the DTMF tones, make it ring, and maybe be able to talk into the receiver. If you want to know why I would want to do this I'll just say I'm a musician, and I'd like to be able to run the phone into my mixer and use it like as an instrument. Also, yes I've seen the instructable about how to make a telephone receiver microphone, so no need to show me.



7 years ago

hook it up to 9V battery in series with resistor 30 - 100 omh.
connect more phones in PARALLEL and you can make a simple telephone network. Look at schematic.


. Analog telephony is commonly called POTS. IIRC, Plain Old Telephone Service. That may not be right, but it helps me remember it. ;) . Try searching for "POTS +circuit" or similar.

Hmm, if I remember correctly, the "off-hook" voltage is far less. If all you want is the DTMF tones and the audio circuit to work, you shouldn't need anything more than a 9v battery. What you won't get is the ringer, or the dialtone. But your DTMF tones will work, and the microphone preamp should work. If you need more than that, you need the telephone simulator that westfw mentioned.


9 years ago

Yes, it can be done. You can buy "phone line simulators"- I have one somewhat that I pulled out of a dumpster; I think I even have a manual. (Are you in the bay area? I'm trying to give away junk. I mean stuff.) There have been various projects using traditional phones as the housing for a modern cellphone (Like this one at SparkFun, and there are projects out there for open-source telephony

If you just want the sounds, the touch-tone frequencies are nice well-defined signals, and you can get them lots of places...

I'm not in the bay area I'm in Arkansas but I will pay for shipping. I'm very interested in that phone line simulator. Getting the DTMF tones is relatively easy from a simulator, but I want the drama of using a real phone on stage.

cool tracks. you made them yourself ? i liked awake the most

iirc it takes 48 V dc to work / 90 V ac 20 HZ to ring. both thru resistor of +- few hundred ohms