Definition of 3270 in The Network Encyclopedia.

What is 3270?

The information display protocol for IBM mainframe computers. The 3270 protocol enables conversations to take place between mainframe hosts and other devices such as dumb terminals, printers, and controllers.

Microsoft SNA Server provides access to resources on mainframe computers by defining and assigning 3270 logical units. These logical units are defined within SNA Server and are configured to use an existing connection to the mainframe system that matches a logical unit resource allocated on the mainframe, usually specified within Virtual Telecommunications Access Method (VTAM). SNA Server client software is installed on client PCs to manage communications between a 3270 application and the SNA Server.