Call management system

Abstract

A call management system connected locally between a central office telephone company switching station (CO) and a conventional single telephone line having multiple extensions provides call paging and intercom capabilities between the multiple telephone extensions. An integrated voltage generator supplies a high voltage, local ringing voltage for ringing the local extensions independent from the CO and a low voltage talk or 'battery' feed to the local telephone when they are operated independently from the CO. Line splitting apparatus temporarily separates the CO from the local extensions when the local ringing voltage is generated by the integrated voltage generator and injected into the local telephone extensions. A hold device mimics an active local telephone off the hook, thereby keeping a call from the CO holding when the local telephones are being used in the paging or intercom modes. Detection devices detect touch tone or rotary dial inputs as well as off hook conditions of local telephones for initiating various local paging and intercom functions between the local extensions. Tone injector apparatus place a dial tone-like sound in the local telephones when they are separated from the CO. A central office ring detector detects a high voltage ring signal from the CO and signals the local users during intercom operation that a call is coming in from the CO and is waiting to be picked up.