Printed circuit board key switch and multiposition socket - uses standard circuit board for switching different circuits in telephone exchange

摘要

A push-button switch with a square body can be inserted in four different positions in any of a number of square sockets mounted on a printed circuit board in telephone exchange equipment. A pair of pins on the switch body connect with a common line and one of four circuits in each socket. Which circuit the switch operates is indicated by markings on the switch and circuit board. Digital addresses for all the circuits are sent on the common lines by an address generator. All the circuits are scanned by a multiplexer to determine which switch is being operated.