User-transparent automatic terminal speed selection

Abstract

Economy and flexibility provide the motivation for using a single set of computer ports for various terminal types. To do this, the communications controller must adapt to the different terminal characteristics. This, in turn, requires that the controller recognize the type of terminal. Many terminal speed recognition algorithms require the user to type a terminal identification character before entering the first command. Entering an identification character detracts from the user interface to the computer. A scheme making terminal recognition almost invisible to the user is described. The implementation recognizes the following terminal types: the IBM 2741, and ASCII terminals operating at 110, 150, and 300 baud. While the algorithm is programmed on the IBM 3705 Communications Controller, it could be applied to other controllers. To make this easier, the algorithm is described in detail, and the techniques generalized.