an apparatus remotely controls , for example , door locking / unlocking and alarm activation of an automobile . a transmitting device transmits communication data , which includes synchronization data and identification data . the communication data is received by the control apparatus in which the identification data included in the received communication data is compared with already stored data . the locking and unlocking of the doors of the vehicle is carried out when the identification data matches the already stored data . a continuous reception condition is detected when the communication data is received for more than a predetermined period of time . when the continuous reception condition is detected , an alarm is actuated . as such , a common transmitting button of the transmitting device can be used to effect both control of the locking and unlocking of doors and alarm activation . the control apparatus may also include an erasable memory which is remotely settable in a writable status and in which identification data can be erased by remote control while in the writable status .