A nonphysical terminal that is defined as a superset of characteristics of a class of physical terminal types. The virtual terminal idea is analogous to defining a non-real-world language into which some set of real-world languages can be translated bilaterally.
In some packet switching networks, attempts have been made to use the virtual terminal concept as a means of performing protocol translation between dissimilar terminals. At the input node the message is translated into the virtual terminal format, and at the output node it is retranslated into the receiving terminal's protocol. The generality of the concept is somewhat limited because of nontranslatable characteristics of certain types of terminals with respect to others.