4 ms·
> because the ringer requires a much higher voltage than can be generated by a small computer. I mean that’s not quite true. A magicjack which is basically an
by danachow 5y ago
> because the ringer requires a much higher voltage than can be generated by a small computer.
I mean that’s not quite true. A magicjack which is basically an ATA is about the size of the Pi Zero and produces ring power. A REN is on the order of 10 mA which at 90V can be generated by a very small (like smaller than a dime) switcher.
Indeed the quickest and easiest way to “modernize” an old phone is probably to stuff the guts of a readily available analog telephone adapter and interface it to a Pi, or a Wi-Fi adapter, etc.
You might even dispense with the pi:
https://randywestergren.com/reverse-engineering-obi200-google-voice-appliance-part-2/ https://randywestergren.com/reverse-engineering-obi200-googl...
- rileyphone 5y agoThis + an ATA like the PAP2T is the easiest way: https://www.oldphoneworks.com/dialgizmo-pulse-to-tone-converter.html https://www.oldphoneworks.com/dialgizmo-pulse-to-tone-conver...
- ale42 5y agoFor the problem of converting pulses to tones, some time ago I made a small circuit that generates the DTMF tones directly inside the phone. It's basically an interface between the rotary dial and the phone line, based on a simple 8-bit PIC microcontroller powered from the phone line (actually coming from an ATA). The idea is to publish it as open source hardware as soon as I find enough time to document it... Downside is that you have to solder it (SMD components) and put it inside the phone...
- danachow 5y agoThe very affordable grandstream ATAs will handle pulse without additional hardware. http://www.classicrotaryphones.com/forum/index.php?topic=20386.0 http://www.classicrotaryphones.com/forum/index.php?topic=203...