The Tektronix 4025 is a "smart" terminal computer because it is capable of editing files and temporarily storing data on its own RAM. One of the S-100 boards has a 8088 CPU. The terminal is incapable of loading or saving information without the mainframe computer. It has a green monochrome screen built in and has composite video output. The computer connects to the mainframe through an old style DB-25 (25 pin) RS-232 serial cable.