elk doorbell detector help


Hi. Wondering if anyone can provide some help on the Elk Doorbell detector. I'll be installing a M1G, but waiting for the new keypads to come out before purchasing. In the meantime, I had attempted to install one of the 930 doorbell detectors and hook it to a contact sensor (such as an X10 powerflash) but didn't have any luck. In testing with a meter and then -reading- the install manual that it doesn't operate the way I thought. The descrption indicates it's an open collector output. I searched on this trying to determine what I can use to make it work, but it's not clear to me.

Would it work to have a seperate say 9v circuit and use the Elk 930 as a series switch? Or is there another way to make this work?

Powerflash + <--- 930 Output <--- 930 Negative <- External 9v + supply
Powerflash _ <------------------------------------------- External 9v - Supply

Open collector basically means switching the negative side of the circuit. Run your 9V+ to the PowerFlash and your 9V- through the 930 and you should have better luck.