Apparatus and method for controlling data transmissions in a communication network

An apparatus for controlling data transmissions in a communication network which includes a plurality of nodes connected to a common bus, each of said nodes having a communication processor with a memory and bus control means associated with the processor for transmitting data from the processor to the network over the bus, said bus control means including a direct memory access controller (DMAC) for accessing parallel data in the memory, means for converting from parallel data to serial data or vice versa, a bus control module for generating a bus acknowledge signal and responding to a bus request signal from the processor and a bus asserting signal from said bus control means during data transmission, and a bus driver for connection with the bus for data transmissions, the apparatus comprising:

• malfunction detect/control means provided in one of said nodes for detecting a malfunction in the network and generating a malfunction signal to said nodes including itself over the bus when the malfunction is detected;
• malfunction detect means provided in each of the other nodes for receiving said malfunction signal from the malfunction detect/control means over the bus;
• diagnosing means provided in every node, responding to the malfunction detect means for diagnosing whether the detected malfunction is occurred in its node;
• and
• wherein in the malfunctioned node, said diagnosing means forces the processor to stop its operation for data transmissions and the malfunction detect means or the malfunction detect/control means also forces the bus control means to disconnect with the bus, thereby removing the malfunction in the network;
• wherein, when said malfunction detect/control means continuously detects a malfunction in the network without receiving of a bus asserting signal, said malfunction detect/control means decides that the malfunction is occurred in the network itself and then produces an alarm to an operator of the network for repair thereof.