Ethernet

General

Ethernet is a cable based data network technology for local data networks (LANs). It enables data exchange in the form of data frameworks between all attached devices in a local area network (LAN) (computers, printers and similar).

Ethernet covers definitions for cable types and plugs, describes signaling for the bit transmission layer and specifies package formats and protocols. Ethernet is standardized in the IEEE - standard 802.3.

Ethernet can be the basis for lan protocols e.g. IPX/SPX, TCP/IP, Ethercat or Profinet.

10 Mbit/s Ethernet with twisted pair cables

10Base - T, IEEE 802.3 Clause 14 – works with 4 wires (two twisted pairs) of a CAT - 3 or CAT - 5  cable. A hub or a switch is placed to the center and offers a port for every participant. The transmission rate is 10 Mbit/s and maximum length of a segment is 100m.

100 MBit/s Ethernet (Fast Ethernet)

Current standard is 100Base - X (IEEE 802.3 Clause 24) for twisted pair cables and fibre cables.

Power over Ethernet

IEEE 802.3af (IEEE 802.3 Clause 33) belongs to the Ethernet standards as well. It describes, how to supply Ethernet devices with power via the twisted pair cable. Devices that are developed for this feature are supplied with up to 48V and up to 15.4W. A logic makes shure, that only PoE devices are supplied with energy.