How to add a transmitter to AP-4/AP-5 gate controllers

Problem: You want to add a new gate opener to your AP-4/AP-5 gate controller but the manuals online are not helpful enough.

I struggled with this problem and wrote up some instructions because I could not find Step 1 online, nor were answers to the FAQs online.

If I help only one person, that would be enough.

These instructions worked for the Linear MCT-3 controller and the Linear MDT-4A. As far as I can tell, they would also work for the Linear MDT-4B.

Step 1: Get the five digit code associated with the new transmitter.

This is a tricky step.

1. Unscrew all four screws on the LiftMaster gate arm controller box (or whatever brand the mechanical element is) so you can access the gate controller. There will be one LiftMaster (or other brand) access box per gate. They’re generally black and about the size of two toasters stacked on top of one another. Inside, find the AP-4/AP-5 controller. It’s the box with all the numbered buttons.
2. Hit any button on the new transmitter and watch for three numbers to display on the AP-4 or AP-5 controller LCD screen.
3. Write those numbers down.
4. Now hit “DISPLAY” and hold it down for 3 seconds.
5. You should see three different numbers. Write those down in front of the three numbers you already have.
6. Cross out the first number.
7. This is the five digit code associated with your new transmitter.

You are ready to add the new transmitter to the AP-4/AP-5 controller.

Step 2: Add the new transmitter to the system.

1. Hold down PROGRAM for 3 seconds. You should hear a soft beep when you release the PROGRAM button.
2. See PiD and then _ _ _ in the display.
3. Enter 3 0 # to add the new transmitter.
4. Enter the 5-digit transmitter ID from step 1.
5. Enter #
6. Enter # again.
7. Hit 1 # to enable the transmitter. [Hit 0 # to disable it.]
8. Hold PROGRAM for 3 seconds.

If your efforts succeeded, hit a button on your transmitter and see if your gate opens. (Try the center button on a three-button transmitter, the left-most button on a two button transmitter, and the upper left most button on a four button transmitter.)

From the AP-5 manual.

Step 3: Program the buttons on the transmitter so one opens Gate A and the other opens Gate B, etc.

1. Hold down PROGRAM for 3 seconds.
2. Enter one of the following codes in 3–7, depending on which button you want to program:
3. 2 1 # for the middle button on the MCT-3 ((top) left button on older models)
4. 2 2 # for the (top) right button on older models
5. 2 3 # for the small tic tac sized button on the top edge older models (where available)
6. 2 4 # for the bottom left button on older models (where available)
7. 2 5 # for the bottom right button on older models (where available)
8. Enter 1 # for Gate A OR 2 # for Gate B]
9. Enter 1 # to enable this button for the chosen Gate[0 # to disable ]
10. Hold PROGRAM for 3 seconds.

You will likely need to run through Step 3 in different variations to get your buttons doing what you want them to do with each gate. Test to make sure you aren’t opening all gates when you push the top left button rather than just opening the one you want.

From the AP-5 manual.

FAQs

I see some numbers on the back of my MCT-3, MDT-4A/MDT-4B transmitter. Are those numbers the 5-digit code I need?

No. The only way you’re getting the 5-digit code is by following Step 1.

Can I program these transmitters to open my residential garage door, too?

If you want to open your residential garage door with a transmitter that can also play nicely with your AP-4/AP-5 gate controllers, you are more likely to have success with an MCT-3 transmitter. The MCT-3 transmitter is compatible with many newer garage door openers that have “learn” mode capability.

However, my LiftMaster Formula 1s have a “learn” mode and do not work with the Linear MCT-3s or the older Linear MDT-4[x] transmitters.

If you happen to know of a 318 Hz transmitter that works with the AP-4/AP-5 gate controllers and any non-Linear garage door opener, please share in the comments.

Where should I buy transmitters? How much should they cost?

I was able to find 1- and 2-packs of MCT-3 and MDT-$[x] transmitters on Amazon Marketplace. I also saw some on eBay. There are other resellers out there.

The MCT-3s can be found for ~$22 each.

The MDT-4A is a little beefier with greater functionality and was $26 + shipping.

Your pricing may vary.

I got the transmitter added to the system, but now multiple buttons on it open the same gate. I only want one button to open each gate. How do I get the buttons all set up?

See Step 3 and note that you may have to go through and disable specific button-gate combinations until your transmitter is opening exactly the right gates (and only those gates) when you push specific buttons. For instance, if all three buttons are opening both gates, you’ll have to disable button 1 for gate 2. Then disable button 2 for gate 1. Then enable button 2 for gate 2 and so forth.