摘要： <正>我们在完成国家六·五科技攻关项目“集散型过程控制成套设备”课题中,

Abstract: This paper presents a non-equalization multiple site Bus-Like data transmit network implemented in the BCM-III microcomputers and Z-80 single-Board computers. The network takes two-level subnet structure, based on the Z 80-SIO to implement CCITT X·25 Link Control Protocol. The network implements the message-bit synchronization through a unified clock, and uses RS-422 interface in the duplex wire media. The intersite transmission is 256 kbit/s. Transmit distance is up to hundreds of metres. Network indexes, such as bit error rate, response time and message capacity, satisfy completely the practical demands of product process controls.