Definition of message protocol

1. in message transfer, the SECS-I message protocol uses the services of the block transfer protocol to send and receive messages. (The block transfer protocol is used by a serial line to establish the direction of communication and to provide the environment for the passing of message blocks.) A message consists of the message data, together with the following information from the header in each block: the R-bit, device ID, W-bit, message ID, and system bytes. [SEMATECH]