5 ms·

The thing I want to see written up in one of these conversion projects: how to drive the ringer.

rovr138 5y ago
It doesn't ring...
andrewstuart 5y ago
You can't drive the ringer unfortunately because it requires a much higher voltage to drive it, something like 48 volts I seem to recall. Two options for getting around that..... You could install a speaker into the phone and play a recording of a phone ringing. You could install a little electric motor with a lopsided head on the axel and position it in between the ringer arms and spin it at the correct hertz and it would ring the bells.
- TimTheTinker 5y ago
  Enough to shock a person. I used to take stuff like this apart as a kid. A call came in while I was in the middle of it (yes, I was playing with the incoming wires). Ouch!
  - jetrink 5y ago
    A fun coincidence: someone posted about a similar memory just this morning[1]! > Removing insulation from a live phone wire with my teeth (I had decided to put an extension in my room without asking for help...) was one of mine, that definitely made me more careful. Went just fine until I closed the circuit with my tongue by accident just as someone called. Not pleasant. 1. https://news.ycombinator.com/item?id=29613712 https://news.ycombinator.com/item?id=29613712
    - kingcharles 5y ago
      That's crazy. I did that too, once. I thought I was the only one stupid enough to accidently strip a live telephone wire with his teeth. https://news.ycombinator.com/item?id=29621055 https://news.ycombinator.com/item?id=29621055
  - function_seven 5y ago
    I used to install T1s back when they were the "fast" way to get online. The vast majority of installations used HDSL to modulate the T1 onto the local loops. HDSL powered the remote card from the one in the central office, using (IIRC) 130VDC. One time I was at a customer prem troubleshooting an installation. The customer's phone vendor was out there with me as we were hunting for the right cable pairs in the terminal. I was getting ready to call another tech back at the CO to put a tone generator on the line when the phone system vendor told me to just run my fingers across the terminals until I got a shock. I thought he was joking. He wasn't. He looked at me like I was a weenie and went ahead and did it himself. Dragged his fingers down the line until I saw him twitch. "Binding posts 47 and 48, right there" I had accidentally shocked myself probably dozens of times, but never as a troubleshooting technique!
- wolfgang42 5y ago
  About 90 volts. (48v is the nominal on-hook voltage; Wikipedia tells me that the official ring voltage spec is 60 to 105 volts RMS at 20 HZ.) This page has a circuit for generating the appropriate signal given a 12 volt input: http://techlib.com/electronics/telephone.html http://techlib.com/electronics/telephone.html (plus a small extra circuit for using a lower voltage for control signals).
- batch12 5y ago
  Couldn't the old magicjacks ring the phone? I seem to remember making Linux 'firmware' for one years ago to do this for kicks..
  - dotancohen 5y ago
    Probably with PWM, a good capacitor, a mechanical relay, and a transformer. Just a guess, I'm not familiar with the hardware.
    - danachow 5y ago
      It’s less than one watt of power - a tiny boost converter and a mosfet is all you need - no transformer or relay necessary - it takes less than a square inch of board space.
      - dotancohen 5y ago
        I didn't realize it was that low - I thought it was a few amps. And even a single amp multiplied by 80 volts is far beyond what I would pump through typical hobby mosfets used with e.g. an Arduino or Raspberry Pi. By yeah, if it's just a watt, that's going to be on the order of tens of milliamps at 80 volts. It probably wouldn't even need a heatsink.
- wumms 5y ago
  This device claims to drive up to 2 phones with mechanical bells from +3.3V to +5V: https://silvertel.com/images/datasheets/Ag1171-datasheet-Low-cost-ringing-SLIC-with-single-supply.pdf https://silvertel.com/images/datasheets/Ag1171-datasheet-Low...
- pwg 5y ago
  > You can't drive the ringer unfortunately because it requires a much higher voltage to drive it, something like 48 volts I seem to recall. You can, provided you also add a boost converter [1] to generate the ring voltage from the input supply voltage. [1] https://en.wikipedia.org/wiki/Boost_converter https://en.wikipedia.org/wiki/Boost_converter
kingcharles 5y ago
I had a device to do just this for old phones. I was always needing this feature for stage productions set in the past; they almost always have a phone that rings at some point and it's much more authentic to have the phone ring than to use the speaker system of the theatre.
danachow 5y ago
People claiming that the voltage is an issue have little idea about modern power conversion. It’s doesn’t take much juice to drive the ringer - less than a watt. Any basic ATA will easily drive a ringer.. ever seen a MagicJack? - it’s a complete USB telephone adapter and barely larger than a thumb drive. They aren’t greatly hackable - but something like a Grandstream HT801 can be opened and the board put inside and you basically have an entire telephone interface right there. They even support pulse dialing.
- hyakosm 5y ago
  A Grandstream ATA drive the ringer for a WE 500 very well.
jacquesm 5y ago
A simple 12V to 120V transformer with a transistor driving it on the 12V side should create enough voltage to do the job.

It doesn't ring...

You can't drive the ringer unfortunately because it requires a much higher voltage to drive it, something like 48 volts I seem to recall. Two options for getting around that..... You could install a speaker into the phone and play a recording of a phone ringing. You could install a little electric motor with a lopsided head on the axel and position it in between the ringer arms and spin it at the correct hertz and it would ring the bells.

TimTheTinker 5y ago
Enough to shock a person. I used to take stuff like this apart as a kid. A call came in while I was in the middle of it (yes, I was playing with the incoming wires). Ouch!
- jetrink 5y ago
  A fun coincidence: someone posted about a similar memory just this morning[1]! > Removing insulation from a live phone wire with my teeth (I had decided to put an extension in my room without asking for help...) was one of mine, that definitely made me more careful. Went just fine until I closed the circuit with my tongue by accident just as someone called. Not pleasant. 1. https://news.ycombinator.com/item?id=29613712 https://news.ycombinator.com/item?id=29613712
  - kingcharles 5y ago
    That's crazy. I did that too, once. I thought I was the only one stupid enough to accidently strip a live telephone wire with his teeth. https://news.ycombinator.com/item?id=29621055 https://news.ycombinator.com/item?id=29621055
- function_seven 5y ago
  I used to install T1s back when they were the "fast" way to get online. The vast majority of installations used HDSL to modulate the T1 onto the local loops. HDSL powered the remote card from the one in the central office, using (IIRC) 130VDC. One time I was at a customer prem troubleshooting an installation. The customer's phone vendor was out there with me as we were hunting for the right cable pairs in the terminal. I was getting ready to call another tech back at the CO to put a tone generator on the line when the phone system vendor told me to just run my fingers across the terminals until I got a shock. I thought he was joking. He wasn't. He looked at me like I was a weenie and went ahead and did it himself. Dragged his fingers down the line until I saw him twitch. "Binding posts 47 and 48, right there" I had accidentally shocked myself probably dozens of times, but never as a troubleshooting technique!
wolfgang42 5y ago
About 90 volts. (48v is the nominal on-hook voltage; Wikipedia tells me that the official ring voltage spec is 60 to 105 volts RMS at 20 HZ.) This page has a circuit for generating the appropriate signal given a 12 volt input: http://techlib.com/electronics/telephone.html http://techlib.com/electronics/telephone.html (plus a small extra circuit for using a lower voltage for control signals).
batch12 5y ago
Couldn't the old magicjacks ring the phone? I seem to remember making Linux 'firmware' for one years ago to do this for kicks..
- dotancohen 5y ago
  Probably with PWM, a good capacitor, a mechanical relay, and a transformer. Just a guess, I'm not familiar with the hardware.
  - danachow 5y ago
    It’s less than one watt of power - a tiny boost converter and a mosfet is all you need - no transformer or relay necessary - it takes less than a square inch of board space.
    - dotancohen 5y ago
      I didn't realize it was that low - I thought it was a few amps. And even a single amp multiplied by 80 volts is far beyond what I would pump through typical hobby mosfets used with e.g. an Arduino or Raspberry Pi. By yeah, if it's just a watt, that's going to be on the order of tens of milliamps at 80 volts. It probably wouldn't even need a heatsink.
wumms 5y ago
This device claims to drive up to 2 phones with mechanical bells from +3.3V to +5V: https://silvertel.com/images/datasheets/Ag1171-datasheet-Low-cost-ringing-SLIC-with-single-supply.pdf https://silvertel.com/images/datasheets/Ag1171-datasheet-Low...
pwg 5y ago
> You can't drive the ringer unfortunately because it requires a much higher voltage to drive it, something like 48 volts I seem to recall. You can, provided you also add a boost converter [1] to generate the ring voltage from the input supply voltage. [1] https://en.wikipedia.org/wiki/Boost_converter https://en.wikipedia.org/wiki/Boost_converter

kingcharles 5y ago

I had a device to do just this for old phones. I was always needing this feature for stage productions set in the past; they almost always have a phone that rings at some point and it's much more authentic to have the phone ring than to use the speaker system of the theatre.

danachow 5y ago

People claiming that the voltage is an issue have little idea about modern power conversion. It’s doesn’t take much juice to drive the ringer - less than a watt. Any basic ATA will easily drive a ringer.. ever seen a MagicJack? - it’s a complete USB telephone adapter and barely larger than a thumb drive. They aren’t greatly hackable - but something like a Grandstream HT801 can be opened and the board put inside and you basically have an entire telephone interface right there. They even support pulse dialing.

hyakosm 5y ago
A Grandstream ATA drive the ringer for a WE 500 very well.

jacquesm 5y ago

A simple 12V to 120V transformer with a transistor driving it on the 12V side should create enough voltage to do the job.