Security & Fire Protection Systems/Protection One K3743


I recently purchased a home which has a Protection One K3743 security system keypad.  The diagram inside the panel box upstairs is labeled ADEMCO VISTA-20P/VISTA-20PSIA SERIES.  The problem is that I don't have the master code. I would like to
use the system as a local alarm only, without an outside service.  Is there any way to find out the master code so I can set up the system?

Thanks in advance.

Hello Mike, and thanks for writing.

In most cases, you can retrieve the Installer's code from Ademco panels, and from this, you can program your user codes.

Be careful -- since you'll be in system programming -- not to change any settings.

Here's how:

If you power down the whole panel by opening it up and taking off the AC power lead on the extreme left and disconnecting the battery then you can power it back up and get into programming. Power the panel back up by connecting the AC power back up to the extreme left terminal, plug in the battery and within 60 seconds go to the keypad and simultaneously push and hold the * and  # keys down until the display shows "20". If you get this then you are in programming.

Then push the # key and 20. This will display a four digit number one digit at a time. This then is the installer code. You can change this code by hitting the * key then 20 and entering in a new four digit number that you want as the installer code.

Once you know the installer code then hit *99 to back out of programming and you should then have your regular display. You can then go back into programming by entering your four digit code plus 800. After you do that you should get a "20". Once again back out of programming by hitting *99 to get your regular display.

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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