Can the PlexiDor Electronic be set up for more than one dog or cat? Yes, the PlexiDor Electronic pet door can be programmed for up to ten pets. The keys that arrive with the door are pre-programmed. If you need to program more collar keys, follow these step-by-step instructions: Remove the motor cover by squeezing from both sides and tipping the cover down and out. Once the cover is removed, you will see the metal spring, motor, and a circuit board. Take the key you want to program and hold it in front of the antenna loop area. Hold the collar key here until you see the blue On/Off light on the door flash. Push and hold the Program Button on the circuit board for approximately 4 seconds, until the Program Light on the board flashes green. You will also hear a quick beep. This means the key is programmed. Test that the procedure worked by holding the key in front of the door. If the panel doesn’t slide up, check that the blue On/Off light is on and blinking approximately every 1.5 seconds. If the blue light blinks rapidly, the door senses a key that hasn’t been programmed. Give us a call at 800-749-9609 if you run into any problems, or if you need to order more keys.