The bipolar LSI MC68194 Carrier Band Modem (CBM) when combined with the MC68824 Token Bus Controller provides an IEEE 802.4 single channel, phasecoherent carrier band Local Area Network (LAN) connection. The CBM performs the Physical Layer function including symbol encoding/decoding, signal transmission and reception, and physical management. Features include: Implements IEEE 802.4 single channel, phasecoherent Frequency Shift Keying (FSK) physical layer including receiver blanking. Provides physical layer management including local loopback mode, transmitter enable, and reset. Supports data rates from 1 to 10 Mbps. IEEE 802.4 standard uses 5 or 10 Mbps.