To facilitate customization and expansion, OMNI-2155 features connector on main CPU box, which houses CPU as well as other essential components on rear of panel. Using plug-and-play approach, each module is connected to CPU box through slot. Total of 8 modules are available: USB/COM/LAN combo module, dual LAN module, MiniCard and SIM card module, RS-232/422/485 module, isolated RS-232/422/485 module, digital I/O module, CAN Bus module, and audio module.