The CTR Electronics CANifier is a CAN-controlled multipurpose LED and General Purpose Input/Output (GPIO) controller. CANifier also supports a variety of sensors including Quadrature, Limit Switch, SPI, I2C, and PWM input/output. CANifier is designed to “CAN-ify” robot control system components that traditionally do not take advantage of CAN bus.

The Controller Area Network (CAN bus) is the nervous system, enabling communication.

In turn, 'nodes' or 'electronic control units' (ECUs) are like parts of the body, interconnected via the CAN bus. Information sensed by one part can be shared with another.

Wikipedia