Implementing a carrier-band node using VLSI

With the IEEE 802.4 token bus standard rapidly gaining acceptance because of its useful features and inclusion in the GM MAP (General Motors manufacturing automation protocol) specification, semiconductor companies are implementing this standard. A carrier-band implementation can provide a low-cost token bus node with up to 10 Mbs data rates. A carrier-band node that includes a token bus controller (TBC), carrier-band modem (CBM), host processor, and memory can be quickly and inexpensively designed using VLSI computer-aided design (CAD) techniques. One such implementation is presented. The token bus controller (TBC) implements the medium-access control (MAC) function in accordance with the IEEE 802.4 standard. The carrier-band modem (CBM) chip implements the 802.4 carrier-band physical layer. An IEEE recommended standard serial interface is used to pass information between the carrier-band modem and the token bus controller