A NEW AUDIO-VISUAL CONTROL USING MESSAGE OBJECT TRANSMISSION

This paper presents a method for controlling audio-visual (AV) devices using message object transmission The validity of the new method is v erified using a trial model. This method realizes system software for performing processes like startup, control and display using the objec t-oriented concept. A control object is transmitted from an AV termina l device to another AV terminal device when they are connected For sta rtup or control, the first AV terminal does not use a control code as was done in the conventional control of AV terminals. Instead it trans mits a message object corresponding to a central object which has been transmitted in advance. The advantages of using this method include t he following: (1) It is possible to absorb differences between devices , for instance difference in control codes; (2) Users need have no kno wledge about device drivers; and (3) The memory capacity required to c ontrol the AV controllers can be minimized. Furthermore, if the AV ter minal's control microcomputer has an RPC (remote procedure call) funct ion, it is possible to control AV terminals in a distributed network e nvironment. This can be done by sending a procedure call to the AV ter minal device in the form of a message to start up the object in the AV terminal device.