Overview#Physical Layer is a Communication Layers and conceptual division of methods in the layered architecture of protocols in the network stack.
Physical Layer defines the relationship between a device and a physical transmission medium (e.g., a copper or fiber optical cable, radio frequency). Physical Layer includes the layout of pins, voltages, line impedance, Cable Connection specifications, signal timing and similar characteristics for connected devices and frequency (5 GHz or 2.4 GHz etc.) for wireless devices.
Physical Layer is responsible for transmission and reception of unstructured raw data in a physical medium.
Physical Layer of Parallel SCSI operates in this layer, as do the Physical Layers of Ethernet and other local Area Networks, such as Token Ring, FDDI, ITU-T G.hn, and IEEE 802.11 (Wi-Fi), as well as Personal Area Networks such as Bluetooth and IEEE 802.15.4.
Physical Layer is never concerned with protocols or other such higher-layer items. Examples of hardware in this layer are network adapters, repeaters, network hubs, modems, and fiber media converters.
More Information#There might be more information for this subject on one of the following:
- Asynchronous Transfer Mode
- Communication Layers
- Data-link Layer
- IEEE 802
- Low-Power and Lossy Network
- Network devices
- Packet segmentation