High Quality Content by WIKIPEDIA articles! The IBM 3270 is a class of block oriented terminals made by IBM since 1972 (known as "display devices") normally used to communicate with IBM mainframes. As such, it was the successor to the IBM 2260 display terminal. Due to the text colour on the original models, these terminals are informally known as green screen terminals. Unlike common serial ASCII terminals, the 3270 minimizes the number of I/O interrupts required by accepting large blocks of data known as datastreams, and uses a high speed proprietary communications interface, using coaxial cable.