buffer and storing these in said input buffer transferring said data words to the data processing means and effecting data processing on the data packet represented by the data words transferred thereto using the transferred data words the input data may be transferred to the input memory via an data input interface which performs hand shaking with a packetized data source of said input data the method may include the step of generating a level filled signal when the input data received by the input memory is such as to fill the input memory to a predetermined level and causing said data processing means to effect said detecting identifying and determining payload size of the data packet and to said generate payload size signal pursuant to generation of the level filled signal the method may include the step of generating an interrupt signal from said level filled signal and directing said interrupt signal to said data processing means to cause said data processing means to effect said receiving the outputted input data from the input memory and detecting identifying and determining payload size of the data packet therein and to generate said payload size signal the method may include the step of generating and directing to said data input interface a further level filled signal when the input thereto of fresh input data is such as to fill the input memory to a further predetermined level and causing said data input interface to generate responsive to receipt thereby of said further level filled signal a data request signal for direction to said packetized data source indicative of a need to modify the data transmission rate of the input data directed to the apparatus from the packetized data source the input memory may be controlled whereby said input.