
The Acre / RS2 Mercury MR52-S3 is a dual-reader interface module that expands an RS2 Access It! or Acre access control system, adding two doors' worth of reader, input, and relay capacity downstream of a Mercury intelligent controller. Because Acre Security acquired RS2 Technologies, this MR52-S3 is fully supported across both RS2 Access It! and Acre deployments, making it the correct expansion board whether you are growing an existing RS2 installation or maintaining one under Acre. It connects to the master controller over a 2-wire RS-485 bus, so you extend door capacity across a facility without home-running every reader back to the panel. Each board supports two card readers, eight supervised inputs for door contacts, request-to-exit devices, and alarm points, and six Form-C relay outputs for strike control and signaling. As a Series 3 (S3) board it carries Mercury's updated processor and enhanced onboard security. Each unit is professionally refurbished, fully tested, and backed by our 1-year hardware guarantee.