OSI Physical Layer (thing)

The Physical layer protocol coordinates the rules for transmitting bits.The layer defines:

• Physical Network Structures
• Mechanical and Electrical specifications for using the transmission medium.
• Bit Transmission encoding and timing rules

The following network connectivity hradware devices are normally associated with the Physical Layer:

• Concentrator, Hubs and Repeaters, which regenerate electrical signals.
• Transmission media connectors, which provide the mechanical interface to interconnect devices to the transmission media.
• Modems which perform digital to analog conversion.