I'm using an ELK-930 to detect ring, which pulls to ground when the ringing voltage is approx 50 volts. It then triggers a relay (ELK-960) which performs the task that I need (shorts two wires for one full second).
This works great with one exception.
The problem is that the ELK-930 follows the ring pattern. I need one-shot and done (at least for a few minutes) for my task.
Yes, I can hang-up after one ring -- that's what I do now and it works just fine. The ELK-930 triggers immediately, so there is a lot of time to hang-up, but I'd really like a more elegant solution.
I could put second relay in the middle with a delay which would ignore further input from the ring detector for a few minutes, but it sounds like the zener diode might avoid that complexity.
I think I understand what you are saying about how a zener diode works: A zener diode placed between the ring/tip just sits there and does nothing until it gets ringing voltage, higher then its zener rating. It then connects the ring/tip, causing a short which "answers" the phone. With the phone answered, the ringing voltage stops, so the zener stops shorting, thus the phone is "hung-up." Do I have that about right?
So that brings up several questions:
Will the zener diode prevent the ELK-930 from detecting ring?
Is it sound practice to just short the lines, rather than simulate a phone (like with a 1200 ohm resistor which was suggested)?
Any other reason this wouldn't work for my application?
Finally, is there an economical source for a 56V/5W zener diodes? I checked Radio Shack, but nothing close to those specs. Found a 56V/5W online for cheap, but the minimum order and shipping/handling was outrageous.
Really appreciate all the help -- I don't know that much about electronics, just enough to be dangerous and have some fun!
