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Ademco Home Alarm System Code Programming

Ademco home alarm system - Ademco 6160 keypad

Ademco home alarm systems have probably been installed in more houses than any other single brand of equipment. If you buy a house, you may find an Ademco alarm system already in place, and might naturally want to start using it.





To operate any home security system, you need a valid security code programmed into it. Alarm system manuals often get lost, along with other paperwork, so you may not know any codes to the system.

Fortunately, your Ademco home alarm system is easy to program, and Ademco manuals are readily available.






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The following steps should only be taken if you own the alarm system, and it’s not currently being monitored by a home alarm company. Programming of a monitored system should always be left to alarm professionals. Otherwise, you could void your warrantee and possibly render the system inoperative. These instructions assume you’ve “inherited” a system with no alarm contract in effect.


Finding Your Ademco Home Alarm System Model Number

If your Ademco is an all-in-one type, with the keypad and panel built as one unit, you most likely have an Ademco Lynx. This system doesn’t have a separate main panel box. If you have an Ademco Lynx, you can skip ahead and get a Lynx user manual.



Ademco Lynx System


For any other type of Ademco home alarm system, find the main panel box. This is a tan-colored metal box about 18 inches square. Most residential security alarms have the main panel located in a closet, laundry room, or utility room. Open the lid to the panel. The lid may be lockable, or held shut with screws. Use the key or a screwdriver, whichever works.



Ademco Vista 20P System



Look inside the main panel lid for a sticker. This sticker shows a connection diagram of the alarm system, along with the model number at the bottom. Your Ademco home alarm system may be a Via, Vista, or other line of panel. Panels are numbered within their product line.

Some common Ademco models include:

  • Via 30pse
  • Vista 10
  • Vista 10P
  • Vista 10se
  • Vista 15
  • Vista 15P
  • Vista 20
  • Vista 20se
  • Vista 20P
  • Vista 25
  • Vista 40
  • Vista 50
  • Vista 50P
  • Vista 128
  • Vista 4140
  • Vista 4140XM
  • Vista 4140XMP
  • Vista 4120

…And there are many more!


Once you identify your model number, you can get user and installation manuals to make future code changes easier. Click here for help finding Ademco Manuals.

The user manual instructions assume you know the master security code, which of course, you probably don’t. These next steps will allow you to reset the master code.




Reset Security Master Code

Disconnect one lead from the backup battery in the main panel. The connectors just push on and pull off, no tools needed.

Remove AC power from the panel. This can be done by removing one of the transformer wires from terminal 1 or 2 on the circuit board. You’ll need a screwdriver for this method. An easier way is to simply unplug the low-voltage transformer. This is a tan or black block, about 2 inches on a side. It will often be located near the main panel box, but could also be in the ceiling outlet for the garage door opener.



Resetting Security Master Code, Battery Terminals


Ademco alarm systems screw terminals


Check a keypad to be sure you’ve removed all sources of power to the system. The keypads should have a blank display and no lights lit. If there are still lights or display, check the battery and transformer connections. Reconnect the transformer, either by plugging it back in, or replacing the wire you removed. Also reconnect the battery lead.





Go to a keypad, and within 60 seconds of power-up, press the “*” and “#” keys at the same time. This will put the panel into programming mode. The display should show either “00” or “20”, indicating program mode. If not, repeat the power-off /power-up steps and try again.

Once the Ademco home alarm system is in program mode, press “#”, followed by either “00” or “20”, whichever digits your keypad displayed. The display will now scroll through 4 numbers, one at a time. Make a note of them; this is the installer code currently programmed into the system.


To change the installer code, press “ * 00” or “ * 20”, whichever your system uses, followed by a new 4-digit code of your choosing.

To exit programming mode, press “* 99”. The keypad should return to an idle display, with green “Power” and “Ready” lights.

If you ever need to get back into programming mode, enter the (installer code), 8, 00.



Programming Additional Codes

To add user codes, first follow the steps in your installation manual to add a master user code. Notice that most Ademco panels require you to repeat the new code a second time to allow changing of the master code. Standard user codes only need the digits entered one time. Once the master code is in the system, it is used to add all the other user codes.

Most Ademco alarm systems follow a similar format for code changes. Enter the (4-digit master code), followed by 8, (2-digit user number), (new 4-digit code). User numbers range from 01 up to 08, 16, or higher, depending on the size of the system. Some older systems use single-digit user numbers.

After you’ve programmed codes into your system, be sure to write them down somewhere safe. You’ll need the user number of any code to make future changes.



Are you the do-it-yourself type?

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