The LNL-500 Intelligent System Controller (ISC) by Lenel serves as the access control engine for an OnGuard system. The ISC provides power, performance, and flexibility for the most demanding applications. Multiple combinations of Input Control Modules, Output Control Modules, and Card Reader Interface Modules can be connected. The ISC can communicate upstream at 38.4 Kbps via RS-232/RS-485 multidropped configuration, modem dial-up communication, or Ethernet TCP/IP networks. The ISC can store up to 12,500 cardholders. The ISC can have two downstream 2-wire RS-485 channels or one 4-wire RS-485 channel. In either configuration, you may connect up to 32 readers or 16 devices. Each device (LNL-1100, LNL-1200, LNL-1300,LNL-1320) uses one device address.