Communications: Voice, Radio and Data - phone internal wiring schematic?

designed strobe board for shop phone need phone internal schematic.
Picked off home phone red and green and sent through bridge rectifier to pick up relay to operate strobe.
Problem is that when board is plugged in, line gets dial tone. Would a capacitor in the line to the bridge rectifier isolate my board from the ring circuit? If so will a small cap do?

It's a bit more complicated than that, but easily doable. It's critical that any circuitry that you attach to a phone line doesn't load it and isolates it from any other circuits or voltage.

Here's an example. (http://www.aaroncake.net/circuits/pflash.asp) The cap and resistor prevents loading the line. The opto-isolator prevents anything downstream from bleeding back into the line.

Or buy a separate phone ringer and use it's output to trigger a relay that controls the device. Radio Shack use to sell them. Sometimes they have a loud bell for noisy locations and sometimes a way to control a light for the hearing impaired.

Why reinvent the wheel (unless you like the challenge of the project, of course) .

This isn't the only gadget that does this, but it's probably what you need:

ELK-930 Doorbell & Telephone Ring Detector (http://www.elkproducts.com/products/elk-930.htm)

Because we're tinkerers, MrRonFL! :)

(You could have said, "Why reinvent the Wheelock (http://www.wheelock-products.com/catalog/dept/9/dept_12.aspx)?") ;)

Yes, you need the capacitor, and a circuit to limit and clamp the ring voltage to that of the relay coil, without overloading the line REN factor.

I made an accessory ringer (an old fire bell though) once. I basically "stole" the line interface electronics from an old cordless phone base, for the phone line side, which was a pass capacitor, rectifier, limiting resistor, zener diode, filter capacitor, current limiting resistor, and an isolator LED.

designed strobe board for shop phone need phone internal schematic.
Picked off home phone red and green and sent through bridge rectifier to pick up relay to operate strobe.
Problem is that when board is plugged in, line gets dial tone. Would a capacitor in the line to the bridge rectifier isolate my board from the ring circuit? If so will a small cap do?

The typical old telephone ringer is capacitor 1 microfarad bipolar 250V in series with a ac ringer (coil with DC resistance of at least 2 kiloohms) This coil has great recistanse for speach and data.

Typical ringing current is 90V 20Hz superimposed on 50V DC.
It is yuite much voltage loss on a long line, Ringing voltage may be as low as 50 V.

dsk