Abstract: An intercommunication and alarm telephone system has a common control in the form of a clock driven central unit connected to an alarm control unit and one telephone line shared by a plurality of station units. The central control unit provides means for answering and placing outside telephone calls to a central telephone office, holding and transferring such calls, giving paging and intercom services, excluding and locking out other stations from outside calls, giving suitable alarms, and such other services as may be necessary or desirable.