The Terminal Unit is a computerized interface between the hardware of the Biomass Compressor and the software on the Control Computer. An ATMega328 mini-module (separate project) serves as the micro-controller of the Terminal Unit. The ATMega328 module can be programmed using the Arduino IDE and an FTDI based USB/Serial adapter. Inside the Terminal enclosure is a circuit board with six 10A relays and a micro-controller. The micro-controller reads signals from pressure transducers and micro switches, communicates the information to the Control Computer, and operates the relays under its direction. The relays are used to actuate the solenoids of the valve manifold. The Terminal Unit runs on 24VDC. An internal DC/DC converter provides a 5VDC for the integrated circuits and LED indicators. The relay stage is designed specifically for our type of solenoid valves. Our solenoids run on 24VDC, so the pole of each relay is hard wired to supply that 24VDC. An array of 36V transient voltage suppressor diodes protects the rest of the system from the voltage spikes created by the relay coils and the solenoids when they are turned on and off. The terminal sports a RS-485 interface to connect with the control computer.