LiftMaster 423LM Three Channel Universal Coaxial Receiver, 390 MHz
The LiftMaster 423LM is a three-channel universal coaxial receiver that adds reliable 390 MHz radio control to a wide range of residential and commercial operators. Designed for retrofit and replacement applications, it integrates with door and gate controllers from most brands by providing three independent, dry-contact outputs, allowing control of up to three separate operators or functions. Its coaxial antenna connection supports remote mounting to improve reception where equipment is housed in metal enclosures or challenging locations, making it a practical upgrade for expanding remote access or standardizing mixed-site equipment to LiftMaster radio controls.
Operating on LiftMaster/Chamberlain Security+ rolling code at 390 MHz, the 423LM is compatible with 390 MHz Security+ remotes such as 971LM, 972LM, and 973LM, and with MAX series transmitters when programmed to Security+ 390; it is not intended for Security+ 2.0 tri-band remotes. The receiver wires to operator control inputs and accepts low-voltage power in the 12–24 VAC/DC range. Setup is straightforward with onboard Learn buttons and indicator LEDs for each channel: mount the receiver near the operator, connect power and trigger leads to the appropriate terminals, and route the coaxial antenna to a clear location for optimal range. For safe operation, follow UL 325 installation practices, keep all mandated entrapment protection devices active, and do not use the receiver to bypass required safety controls.
