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:
“What climbs the stair?
Nothing that common women ponder on
If you are worth my hope! Neither Content
Nor satisfied Conscience, but that great family
Some ancient famous authors misrepresent,
The Proud Furies each with her torch on high.”
—William Butler Yeats (1865–1939)
“The glance is natural magic. The mysterious communication established across a house between two entire strangers, moves all the springs of wonder. The communication by the glance is in the greatest part not subject to the control of the will. It is the bodily symbol of identity with nature. We look into the eyes to know if this other form is another self, and the eyes will not lie, but make a faithful confession what inhabitant is there.”
—Ralph Waldo Emerson (1803–1882)