This board is a behavior port interface board for Bpod. It connects Bpod Finite State Machine via an Ethernet cable, to a behavior port mounted inside your experimental chamber. It includes screw terminals to connect an infrared emitter, a phototransistor, a visible LED and a solenoid valve. It is compact enough to mount vertically behind adjacent ports that are 5mm apart. The board contains a thumbwheel potentiometer connected to adjust the current (and consequently, brightness) of the port LED. This allows the experimenter to calibrate the maximum brightness of multiple ports.