Physical Layer The job of physical layer is to send individual bits from one node to a directly connected node Address the communications issue The physical layer also covers the physical interface between a data transmission device(e. g computer) and a transmission medium or network It is concerned with specifying characteristics of the transmission medium the nature of the signals the data rate, and related matters Examples Ethernet has many physical layer protocols: one for twisted-pair copper wire another one for coaxial cable some others for optical fiber, and so on EEE 802.11b, 802.1la, 802.11g are different physical protocols for Wireless lan, each with different transmission capabilities 1818 Physical Layer • The job of physical layer is to send individual bits from one node to a directly connected node. — Address the communications issue • The physical layer also covers the physical interface between a data transmission device (e.g., computer) and a transmission medium or network. • It is concerned with specifying characteristics of the transmission medium, the nature of the signals, the data rate, and related matters. • Examples: — Ethernet has many physical layer protocols: one for twisted-pair copper wire, another one for coaxial cable, some others for optical fiber, and so on. — IEEE 802.11b, 802.11a, 802.11g are different physical protocols for Wireless LAN, each with different transmission capabilities