!!! Overview [{$pagename}] is a [Communication Layers] and conceptual division of methods in the layered [architecture] of [protocols] in the [network] stack. [OSI-Model] [{$pagename}] defines the electrical and physical specifications of the [data] connection. [{$pagename}] defines the relationship between a device and a physical transmission medium (e.g., a copper or fiber optical cable, radio frequency). [{$pagename}] includes the layout of [pins|Cable Connections], 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. [{$pagename}] is responsible for transmission and reception of unstructured raw [data] in a physical medium. [{$pagename}] may define transmission mode as simplex, half duplex, and full duplex. It defines the [Network topology] as [BUS], mesh, or ring being some of the most common. [{$pagename}] of Parallel [SCSI] operates in this layer, as do the [{$pagename}]s 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]. [{$pagename}] is the layer of low-level [Network devices], such as some [Network hubs], cabling, and [Network Repeaters]. [{$pagename}] is never concerned with [protocols] or other such higher-layer items. [Examples] of [hardware] in this layer are network adapters, [Network Repeaters], [Network hubs], modems, and fiber media converters. !! More Information There might be more information for this subject on one of the following: [{ReferringPagesPlugin before='*' after='\n' }] ---- * [#1] - [OSI_model|Wikipedia:OSI_model|target='_blank'] - based on information obtained 2017-04-01