Ringing the bells

[royalbox]

The PowerDsine ring generators have arrived. They're smaller than I though just over an inch square. They work, but they build-up over the first half second or so. Maybe because they're only 50V output, I don't know. We already knew this was on the low side.

The inhibit line is low (0V) and stops the bells when connected to the +12V in.

I don't know how the F0 and F1 outputs work. I know they're to do with changing the frequency as these units run at 17/20/25Hz. They output AC just like the outputs but at a much lower voltage. F0 measured ~2.25V and F1 ~2.8V. Any thoughts on that would be welcome.

EDIT: Just for reference, I measured about 75mA on the DC side while the bells were ringing. The bell coils on the phone tested are the later 2000 Ohm ones, so 4K Ohm total, I don't know if that makes a difference.

Can't find any datasheet online for these. They have a date on the side of: Feb 98.

[royalbox]

Here's a short clip of the phone ringing with US and UK cadence with the ring generator. As you will hear, the build-up effect is not great especially on the short UK rings.
Next test will be on a trimphone, I'm hoping it will be better on one of those.

I haven't got the equipment to do decent videos and the sound quality is poor, sorry about that.

[TelePlay]

I asked the seller for a circuit diagram of the device and he gave me a link to what seems to be the general data sheet covering more than one type of these ring generators.

     https://pdf1.alldatasheet.com/datasheet-pdf/view/227078/ETC2/PCR-SIN15V48F00.html

A copy of the 6 page document is attached in PDF format. I have not looked through it in detail so don't know much about it. If interested, here it is.

[royalbox]

Thanks for posting that. It's not quite the same but still useful.

I don't know what I did but one of mine has let off the magic smoke and died.

I did get to try it on a trimphone before it died and it worked. There's a noticeable delay between pushing the button and it sounding maybe 100 milliseconds at a guess. When the on time for a UK ring is only 400 milliseconds it makes a big difference. It does say in the PDF you posted that you should use the inhibit wire to control cadence as this ensures that the output starts and stops at a zero crossing. Maybe it will be less of a delay too but reluctant to try it at the moment in case I ruin another one. Really would like to learn to make one. Anyway, will post any updates if I find anything interesting.