The XR550 features 574 inputs, 10 On-Board Zones, 16 keypads = 64 zones, 5 built-in LX Bus (100 Zones per LX), and 10,000 user codes with 99 profiles. It provides ease of programming, network connectivity, systems integration, flash updates plus intuitive operation designed with end-users in mind. Includes 50VA transformer. Compatible with all DMP Keypads. The XR550 supports 32 doors of access (via 7073 or 734/734N) and upgradable to support 96 doors of access.