Circuit arrangement for dial keypads in communications terminals

摘要

For dial keypads in communications terminals which produce line interruptions by means of a microcomputer and electronic control devices for pulse transmission and which are supplied with power via the connection lines, it is proposed to assign to the dial keypad a monostable relay which is held in the working condition during dial pulse transmission via the discharge of a capacitor, and to equip the arrangement with a parallel voltage regulator and a series voltage regulator, a substantial reduction in component cost being achieved through multifunctional use of the regulators in conjunction with the monostable relay, without any functional impairment.