Abstract: A communicating method between two processors in a decentralized multi-node exchange system comprising a central processing module for controlling the system by processing events related to a call process, and a signal processing module having a common memory, for transmitting/receiving a signal message generated in the exchange system to/from the central processing module through the common memory. In order to transmit a message through the common memory, the message is transmitted to a message transmitting buffer when the message transmitting buffer is emptied, and an interrupt is generated to a counterpart receiving the message when the transmitting buffer is not emptied. Meanwhile, in order to receive a message, the number of receiving messages is set during a period of time when the interrupt is received or when it is set to receive a message, and a message corresponding to the number of the receiving message is read from the common memory.

Abstract: A data communication method between a master system and multiple slave systems using a serial input/output interface. The master system connects a communication path to a corresponding slave system, and transmits a message and simultaneously receives a message from the slave system during an assigned communication time. When the transmission of the message ends, the master system transmits a final message and when a final acknowledgement message is received, performs a service for the next slave system. Meanwhile, the slave system receives a message transmitted by the connection of the communication path and simultaneously transmits a message to the master system. Further, when a final message is received, the slave system transmits a final acknowledgement message to the master system. Thus, the effective communication between point-to-multipoint can be achieved.