Security & Fire Protection Systems/NAPCO GEM P800 and VOIP


The subject system has worked fine for 14 years.  When I switched its dial-out line from copper to VOIP (AT&T) service it could no longer recognize the monitoring handshake--it keeps trying again and again without success.

Is there a keypad programming that will change its commo format to one compatible with VOIP?

Hello Hal, and thanks for your question.

The short answer is, "no." There's nothing programmable for your system that can make it compatible with VoIP. You'll need, at a minimum, some additional hardware.

Here's an article that gives some detail:

What you should do is contact your service provider or monitoring center, and let them know what you've done. They will be able to guide you.

There are do-it-yourself solutions, but I don't recommend them (just Google "alarm voip" and you'll find some). There are too many variables, and the best way is to have a qualified alarm technician do the work.

The two main issues are setting it up so that the alarm system can seize the VoIP line if it's in use, and to ensure that there's backup power for your router/modem so that it'll work during a power failure.

I hope this helps!

Best Regards,


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Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


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