Ok thanks. How critical is diode d2 as toys what I'm missing?

 

Here's another scheme that I like much better. It uses a full wave bridge which makes it much easier to filter the ring signal. As in my first schematic do not ground the emitter side of the Opto.

 

Ok thanks. How critical is diode d2 as toys what I'm missing?

The two Zeners in your original circuit aren't needed to lower the ring voltage going to the emitter of your Opto. Instead, they're there to prevent AC noise spikes on the Tel line from false biasing the opto. Since we're heavily filtering the ring signal we don't need them. You will note that I didn't use them in the Bridge circuit that I posted last.

By the way, don't discount the post by #12 where he suggested an NE2 neon and an LDR (Light Dependent Resistor). It's an effective way of doing this.

 

Great stuff. I used your initial circuit, it was the lack of the diode D2 that was causing me the problem, now get two relay clicks on my receiver per ring cycle which is what i need!!

Thanks for your help

 

Glad to hear that. The ring voltage can vary quite a bit, depending upon how many phones are on the line and distance from the PBX. If you ever run into a ring voltage too low to consistently operate your circuit, consider using the Bridge circuit I posted. It's a much better design that will work with much lower ring voltage.