971LM

Red learn button logic board panel

Chamberlain / Liftmaster Remotes: continued (Part II):
Last post I talked about two earlier versions of Liftmaster receiver technology. This time I want to move to the next generation of remote controls, the "rolling code" technology, called "Security +". This version is identified on the powerhead by a RED or ORANGE square button, located above the antenna wire. This technology was used on machines made by Liftmaster between 1997 and 2005. This machine uses the 97XLM series of remotes, of which the 971LM is still available.

With the rolling code technology, every time the user presses the programmed button on the remote, a different code is transmitted to the receiver. When the remote is programmed, the receiver memorizes the identity of the remote, so the code doesn't matter. What this random code generation does, is prevent some potential thief with a scanner from learning the code of your operator, and cloning that code to use to get into your garage. The RED learn button machines receive on the same 390 Mhz, but as you can see, the technology is different than either the green learn button or the yellow/white/gray//DIPswitch technology I talked about yesterday, because both the transmitter and the receiver have to 'speak' the same language, so to say, in order to communicate.

Not only are the newer technology (post DIPswitch) remotes easier to program, but they are more secure. The only drawback is that there is a limit to the memory capacity of the powerhead of only 7 remote devices (for residential operators). This means that unless or until you specifically erase all devices from the memory in your learn button machine, any remote devices, including wireless keypads, will stay in memory, even if they wear out or get lost or stolen. If you reach the maximum memory limit, either the receiver will refuse to accept a new remote device or it may randomly kick out previously programmed devices to make room for the new one. That is one area where the older DIPswitch machines have both an advantage and disadvantage: Virtually any number of compatible remotes can be programmed by DIPswitch to open a garage door or gate, which is great for gated communities for instance. The downside is that you can't realistically limit the number of remotes which can be programmed in order to control who has access.

Erasing the memory of any of the 'new' technology machines is very easy --maybe too easy in some cases: When you press the smart button, also known as the learn button, learn code button, or program button on the powerhead, while programming a new remote device, you must only press that button for about a second; just long enough for the indicator light to come on. If you hold that same button for 6-10 seconds or more, the memory is erased and NO remote devices held in memory  in that machine will work... until you RE-program them into the machine, using the correct instructions for your remote device.

Okay, that's enough blather for today. Next time we will attempt to get to the newest Liftmaster technologies, using the purple and (new) yellow learn buttons. Remember to check out www.Liftmaster-store.com for any new remotes you may need for the technologies we have discussed. Also, hopefully next time we can talk about the newest Liftmaster technologies, the purple and (new) yellow learn buttons machines.