1. A method for use with a multiplexed data bus having a plurality of data processing units coupled thereto which provides for direct addressing of respective computer memories associated with each of said data processing units to store received data messages therein, said data processing units including a vector table and an input control block which are established by software functions executed by said data processing units, said data message comprising a functional address identifying a data processing function to be performed on data in said data message and data to be transferred into said memory, said method comprising: receiving said data message containing said functional address; using said functional address as an index in said vector table, said functional address pointing to an input control block corresponding to that particular functional address; addressing said input control block designated by said functional address; utilizing said input control block to designate a computer meory location where data in a received data message is to be stored; and storing said data contained in said received data message in said computer memory location designated by said input control block.