A multi-parameter patient monitoring device rack can dock a plurality of patient monitor modules and can communicate with a separate display unit. A signal processing unit can be incorporated into the device rack. A graphics processing unit can be attached to the display unit. The device rack and the graphic display unit can have improved heat dissipation and drip-proof features. The multi-parameter patient monitoring device rack can provide interchangeability and versatility to a multi-parameter patient monitoring system by allowing use of different display units and monitoring of different combinations of parameters. A dual-use patient monitor module can have its own display unit configured for displaying one or more parameters when used as a stand-alone device, and can be docked into the device rack when a handle on the module is folded down.