I just purchased a home w/ an existing wireless system (safewatch 2000). I didn't and don't have any codes. I unpluged and disconnected the battery in hopes of making it work. I called ADT, they are not willing to help w/o a long contract. I am not interested in it being monitored just working. PLEASE!! PLEASE!! PLEASE!! help.

 

Safewatch 2000 is about the same as a Vista-20se.

Peruse some of the previous posts regarding Ademco type systems.

To get the installer code (needed to change the master code);

Unplug battery, unplug AC power. Wait a minute. Plug the AC power back in. Within 50 seconds, press * + # on the nearest keypad. When the keypad prompt shows a 20, press #20. This will read back the installer code 1 digit at a time (It is most likely 6321). Exit program mode with *99.

Next:
[Installer code] + 8 + 02 + [New Code] should Program a nwe master user code.

The user manual for these systems is available for free from either the ADT or Honeywell/Ademco website. The installer manual is available from a number of online vendors for pretty much a nominal fee.

You will eventually need to go back into programming to remove the ADT dialer settings, because it will eventually go into communication trouble, but it's not that difficult.