Ringing a landline Phone on stage

[Seekonk]

One thought is to use a Self-Oscillating HALF BRIDGE basically a 500V 555 oscillator like IR51HD224.  I have a number I bought for about a buck each.  Two in series would give you spacing and tone.  Personally I would do it with $2 mega328 and a FET.

[David_AVD]

The ringer I designed uses a micro driving a couple of NPN transistors which in turn drive the 12V winding of a small mains transformer.  The 240V winding feeds the phone output.  I also have off-hook detection so it stops ringing when the phone is picked up.  It has start and stop button inputs as well.  The micro allowed me to create Australian and USA ring cadences.

[jlmoon]

hey guys,
The phone needs to be a digital sounding one (not a old school bell). The phone is very similar to this one pictured below.

Thanks
Ian

Make a chopper out of a 555 timer set for 20 cps wave form at 5 volts and hook to the opto isolator (transistor side - observing correct bias)  that senses the incoming ring voltage on Tip and Ring.  Control the power to the 555 and you can ring that electronic phone until the cows go home.  Just like the phone company does but on the other side of the isolator.. 

[jlmoon]

Typically the type of phone pictured there has either a large zener or a neon or gas spark gap tube with the yelping circuit in series with it and it yelps along with the low frequency ring signal. 90 volts is what it takes here in the states to get them to ring. Look up a ring generator. You can get them second hand online. Be careful though. They can zap you and knock you on your butt pretty good! Old fashioned bell ring telephones just have the coil to the clapper arm of the ringer connected across the line. This had two purposes. One, the phone will instantly ring when the ring signal comes, and two tells the telephone company a phone is connected by keeping the circuit closed. The audio signal is so low it does not move the clapper enough to ring. On some old phone designs the clapper was sensitive enough that you could hear the audio off of it like a speaker if the design did not take it out of the circuit when the receiver was off the hook.

I remember the days when electrical storms would come through and the phone would go DING.... I knew lighting hit the phone lines nearby.

[spencerlinn]

I know this is probably way too much equipment to buy just to get a phone to ring, but perhaps a Cisco 2801 or 2811 router with an FXS card would work? The FXS cards have at minimum a few RJ11 jacks and as per the name, act as a Foreign Exchange Station - generating the analog voice signals and ringing voltage as well. Normally these FXS cards are used in a Cisco VoIP phone system to allow it to interoperate with analog phones as well, but you might be able to set up just two analog phones and call one from the other, or even use the Cisco IP Communicator software phone on a laptop with WiFi (and a WiFi router plugged into the Cisco router with related IP network configured) to initiate the ringing. It wouldn't involve the telco, and you can set the ringing to any cadence and frequency you like, I believe. Like I said, it'd be a fair bit of setup and probably not worth it for a single use, but hey, it'll give you plenty of flexibility to set up your system and not have to modify any phones!

[tautech]

Hey guys

I am doing a show where the phone has to be rung from off stage. I am having trouble finding any information on how these land line phones work.

The phone i want to ring is a normal Australian Landline phone with a RJ11 connector.

Does anyone know the voltages and such to ring a normal land line phone?

I have found this http://www.tele-q.com/operating.php which is exactly want but I the price is a bit high to ring a phone once or twice a show. Does anyone know how to do this simply and cheaply?

Thanks Ian

Easy really.
Here in NZ std phones on the same line as another can be all rung with 137 entered in the keypad and then hung up.
Handy for the wife to let me know when its dinner time when I'm in the garage.

For the OP's needs, set up the stage phone on an extension jack with another working (live) phone, turn off the ringer on the remote one, then have somebody dial the stage phone on cue.

It will ring until picked up.

So corner an Aussie Telco tech and confirm the self-dial # and you'll be set to go.

[janoc]

Easy really.
Here in NZ std phones on the same line as another can be all rung with 137 entered in the keypad and then hung up.
Handy for the wife to let me know when its dinner time when I'm in the garage.

For the OP's needs, set up the stage phone on an extension jack with another working (live) phone, turn off the ringer on the remote one, then have somebody dial the stage phone on cue.

It will ring until picked up.

So corner an Aussie Telco tech and confirm the self-dial # and you'll be set to go.

I think the point was to ring the phone when you don't have it hooked up to a landline. Otherwise the OP could simply call it from another phone, no?

[David_AVD]

Exactly.  Relying on a real land line is not really practical for most theatre applications.

[Zucca]

I would have played a telephone sound by using the theater speakers. Not realistic, but good enough.

[kolbep]

With everything going to VOIP nowadays,
there are lots of offices with 2nd hand analogue PABX's lying around (Dave even did a teardown of one when he moved into the EEVblog world headquarters).
You just have 2 hook the 2 phones up to it, and then dial the internal number for the stage phone (eg 204 or whatever).
And you do not need an external telko line, just the 2 phones plugged in (on on stage, one off stage), and the power into the pabx.



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