Implementation issues for an IEEE 802.4 token bus LAN carrierband physical layer

The IEEE 802.4 standard for a token-passing bus LAN (local area network) provides for a single media access protocol for use with multiple physical layers. The single-channel phase-coherent FSK (frequency-shift-keyed) or carrier-band standard is the best choice for a cost-effective, easily configured, high-speed physical layer suitable for industrial applications. The author provides a brief background on the IEEE 802.4 physical layers and then expands into an overview of the carrier-band physical layer. The overview describes the carrier-band modulation and introduces the key elements of the associated cable plant, including cables, taps, and signal budget. Implementation issues, including associated hardware, connectors, cables, taps, installation and maintenance, and redundancy, are discussed