In telecommunication, a common control is an automatic telephone exchange arrangement in which the control equipment necessary for the establishment of connections is shared by being associated with a given call only during the period required to accomplish the control function for the given call. The first examples deployed on a major scale were the Director telephone system in London and the panel switch in the Bell System. Direct control telephone exchanges became rare in the 1960s, leaving only common control ones.
Note: During the 1980s, common control exchanges became stored program control exchanges, using common-channel signaling in which the channels that are used for signaling, whether frequency bands or time slots, are not used for message traffic.
Famous quotes containing the words common and/or control:
“If music in general is an imitation of history, opera in particular is an imitation of human willfulness; it is rooted in the fact that we not only have feelings but insist upon having them at whatever cost to ourselves.... The quality common to all the great operatic roles, e.g., Don Giovanni, Norma, Lucia, Tristan, Isolde, Brünnhilde, is that each of them is a passionate and willful state of being. In real life they would all be bores, even Don Giovanni.”
—W.H. (Wystan Hugh)
“There is one thing you and I as parents cannot do, not do we want to do if we really think about it, and that’s control our children’s will—that spirit that lets them be themselves apart from you and me. They are not ours to possess, control, manipulate, or even to make mind.”
—Barbara Coloroso (20th century)