• Hardware

  • Making a land-line phone ring at will on stage

My dad is working on this new play he's directing and they need a way to make a phone (or more) to ring whenever they want.

For example, the phone has to ring at will by pressing a button in the appropriate scene. We have done it before on old bell based phones, but we don't know how to do it on modern phones. I either need some sort of way to make them ring at will, or I need some sort of transformer that converts the AC power to 50V DC (50V is needed to make the phone ring)

Any help?
AvoK95 wroteMy dad is working on this new play he's directing and they need a way to make a phone (or more) to ring whenever they want.

For example, the phone has to ring at will by pressing a button in the appropriate scene. We have done it before on old bell based phones, but we don't know how to do it on modern phones. I either need some sort of way to make them ring at will, or I need some sort of transformer that converts the AC power to 50V DC (50V is needed to make the phone ring)

Any help?
either you need to call the phone the easy way or you can try and create a ring signal, what you said is not right around -50 VDC is what is normally present on the phone line at any time and the ring signal is somewhere around 100 volts AC at maybe 50hz(am not sure).

so in order to make the phone ring you should send 100VAC at 50hz to it, if thats the case that is very easy to do.

give me some time i am gonna do some tests to see exactly what are the voltages and frequencies and try to make it ring if it works i'll get back to you.
Calling the phone is out of the question because:
1- No land lines on stage
2- There's too much delay between the call and the time it takes to ring
3- phone signals will be horrible in the theater

@DNA, yeah needs around 100V. Is there some sort of transformer for that or something I can get online or locally? Or a way I can make my own somehow? I got until April for them to go live.

We were thinking about just playing a phone soundtrack or something as it would be easier, but I think it would be better if the physical phone rings as it would be much more realistic
How about hiding a small but powerful speaker behind the phone and playing the sound? It should do the trick.
Fellows, why not do what they do on stage? They use a toy phone that looks real, which is connected to another toy phone backstage. You just click the call button and the other phone rings. You can even talk and tell the actor what to say
Nabs wroteFellows, why not do what they do on stage? They use a toy phone that looks real, which is connected to another toy phone backstage. You just click the call button and the other phone rings. You can even talk and tell the actor what to say :P
I like this idea. Any idea where such phones are sold? And what their cost is?
I believe it's pretty easy. A lot of the phone technology dates from the first half of the (last) century, and I believe making a phone ring is pretty simple, something like sending a constant voltage or something like that... but I don't know any specifics, so you should Google it.

PS: no need to have landlines, if you can get your hands on an old "central" (internal phone exchange) that many companies use to make internal, office-to-office calls, it would solve your problem!

Make sure you have a ringing sound pre-recorded and ready at the "regie", as backup, in case your system breaks down.
rolf wroteI believe it's pretty easy. A lot of the phone technology dates from the first half of the (last) century, and I believe making a phone ring is pretty simple, something like sending a constant voltage or something like that... but I don't know any specifics, so you should Google it.

PS: no need to have landlines, if you can get your hands on an old "central" (internal phone exchange) that many companies use to make internal, office-to-office calls, it would solve your problem!

Make sure you have a ringing sound pre-recorded and ready at the "regie", as backup, in case your system breaks down.
Aren't centrals expensive?
AvoK95 wrote
rolf wroteI believe it's pretty easy. A lot of the phone technology dates from the first half of the (last) century, and I believe making a phone ring is pretty simple, something like sending a constant voltage or something like that... but I don't know any specifics, so you should Google it.

PS: no need to have landlines, if you can get your hands on an old "central" (internal phone exchange) that many companies use to make internal, office-to-office calls, it would solve your problem!

Make sure you have a ringing sound pre-recorded and ready at the "regie", as backup, in case your system breaks down.
Aren't centrals expensive?
I dont know but my reasoning is that they have been used for decades so it would be possible to get an old one for cheap, or find one to borrow.

By the way, this might help:
http://www.overclockers.com/forums/archive/index.php/t-283831.html
@Avok i checked the line today Ogero's phone line voltage is -54.5 Vdc and the ring signal is somewhere between 50-90 Vac at 25Hz. I tested a simple circuit to a my phone and it can ring at 50-100Vac at 50hz no problem. it doesn't need to be at 25hz(which makes it a lot simpler) and also it's not necessary to have the DC voltage present in the line.

if you feel safe and comfortable playing with mains current i can tell you how to make a simple circuit using 1 or two small transformers and a resistor one problem though is that the phone will ring continuously with no pauses, you can simply connect a switch or button in which someone can make the pauses (press for 2 second release for another 2).

if you want to make your circuit a bit more complex we can connect a simple oscillator circuit to the previous one so it can generate the pauses automatically.

other than that you can either go with Nabs solution if you can find it somewhere, or maybe you can use a wireless phone in which the base will be backstage and someone can press the intercom button and the handy will ring.