The LiftMaster 312HM Coaxial Receiver (Security+ 315 MHz) is a single-channel, add-on radio receiver designed to let older or third‑party gate operators, commercial door operators, and access control inputs accept LiftMaster/Chamberlain Security+ rolling‑code transmitters. Operating at 315 MHz, it features a coaxial F‑connector so the included remote‑mount antenna can be positioned away from metal enclosures for improved range—ideal for warehouses, parking structures, and metal buildings. The receiver provides a momentary dry‑contact output (NO/COM) that wires directly across a wall‑control or activation input, and it powers from 12–24V AC or DC, making it a versatile upgrade or replacement part for residential or commercial applications.
Compatibility is limited to Security+ 315 MHz transmitters, including common LiftMaster/Chamberlain models such as 371LM, 372LM, 373LM, 374LM, and the 377LM wireless keypad; many MAX‑series remotes can also be configured to Security+ 315. It is not compatible with 390 MHz Security+ or Security+ 2.0 (yellow learn button) unless the transmitter supports 315 MHz Security+ mode. Programming is straightforward using the receiver’s Learn function to enroll each transmitter. For best performance and safety, mount the unit in a dry, protected location, route the coaxial antenna to a clear area for reception, and install per UL 325 and local codes when integrating with gate and commercial door systems.
