question: How does Powerline Ethernet work, how can Data transfer over electricity cable?
comment: Data transfer is nothing more than something being sent from a sender to a receiver in a meaningful way. In the case of copper cables the information you are sending is sent as electrical pulses over the physical cable. An Ethernet cable is purpose built for this task, but inside the cable is just copper wires that allow the electrical signal to travel over it. Powerline Ethernet is a standard in which electrical pulses at a specific frequency and amplitude are sent and received from the wall adapters. The receiving and sending devices are tuned to listen for and understand. These electrical pulses. Essentially, instead of using a specific cable (Ethernet cable) you are just using the existing cable inside your home/building.
passages: The most widely deployed powerline networking standard is from the HomePlug Powerline Alliance. HomePlug AV is the most current of the HomePlug specifications and was adopted by the IEEE 1901 group as a baseline technology for their standard, published 30 December 2010. HomePlug estimates that over 45 million HomePlug devices have been deployed worldwide. Other companies and organizations back different specifications for power line home networking and these include the Universal Powerline Association, SiConnect, the HD-PLC Alliance, Xsilon and the ITU-T’s G.hn specification.
  
  Section::::Broadband over power line.
   Power line communications can also be used in a home to interconnect home computers and peripherals, and home entertainment devices that have an Ethernet port. Powerline adapter sets plug into power outlets and establish an Ethernet connection using the existing electrical wiring in the home (power strips with filtering may absorb the power line signal). This allows devices to share data without the inconvenience of running dedicated network cables.
   The signal is sent from the telco's central office as an Ethernet style signal and is demuxed at the customer's premises by a POTS/Ethernet splitter. The box itself contains all the circuitry needed to split the data and voice channels. An Ethernet cable is run directly to the customer's PC or router, and the POTS lines within the home are connected to the POTS terminals inside the customer-premises equipment (CPE) unit. The CPE unit is powered from the telco's central office, and will continue to work during a power outage, and supports failover-to-POTS.
  
  Section::::External links.
  
  BULLET::::- HVDL vendor Charles
   Ethernet Powerlink
  
  Ethernet Powerlink is a real-time protocol for standard Ethernet. It is an open protocol managed by the Ethernet POWERLINK Standardization Group (EPSG). It was introduced by Austrian automation company B&R in 2001.
  
  This protocol has nothing to do with power distribution via Ethernet cabling or power over Ethernet (PoE), power line communication, or Bang & Olufsen's PowerLink cable.
  
  Section::::Overview.
  
  Ethernet Powerlink expands Ethernet with a mixed polling and timeslicing mechanism. This provides:
  
  BULLET::::- Guaranteed transfer of time-critical data in very short isochronic cycles with configurable response time
   Picture 3: Time slots in EPL multiplexed mode.
  
  Poll response chaining
  
  Mode used mainly for robotics applications and large superstructures. Key is lower number of frames and better data distributions.
  
  Section::::OpenSAFETY.
   Some Cisco manufactured WLAN access points and IP phones supported a proprietary form of PoE many years before there was an IEEE standard for delivering PoE. Cisco's original PoE implementation is not software upgradeable to the IEEE 802.3af standard. Cisco's original PoE equipment is capable of delivering up to per port. The amount of power to be delivered is negotiated between the endpoint and the Cisco switch based on a power value that was added to the Cisco proprietary Cisco Discovery Protocol (CDP). CDP is also responsible for dynamically communicating the Voice VLAN value from the Cisco switch to the Cisco IP Phone.
   BULLET::::- Isochronous Phase: The Managing Node calls each node to transfer time-critical data for process or motion control by sending the Preq - Poll Request - frame. The addressed node answers with the Pres - Poll Response - frame. Since all other nodes are listening to all data during this phase, the communication system provides a producer-consumer relationship.
  
  The time frame which includes Preq-n and Pres-n is called time slot for the addressed node.
   Section::::Medium frequency (100 kHz).
  
  Section::::Medium frequency (100 kHz).:Home control (narrowband).
  
  Power-line communications technology can use the electrical power wiring within a home for home automation: for example, remote control of lighting and appliances without installation of additional control wiring.
   Power is supplied as a common-mode signal over two or more of the differential pairs of wires found in the Ethernet cables and comes from a power supply within a PoE-enabled networking device such as an Ethernet switch or can be injected into a cable run with a "midspan" power supply. A midspan power supply, also known as a "PoE power injector", is an additional PoE power source that can be used in combination with a non-PoE switch.
   Power over Ethernet
  
  Power over Ethernet or PoE describes any of several standard or ad-hoc systems which pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices such as wireless access points, IP cameras, and VoIP phones.
   Notes:
  
  Section::::Standard implementation.:Powering devices.
  
  Three modes, A, B, and 4-pair are available. Mode A delivers power on the data pairs of 100BASE-TX or 10BASE-T. Mode B delivers power on the spare pairs. 4-pair delivers power on all four pairs. PoE can also be used on 1000BASE-T, 2.5GBASE-T, 5GBASE-T and 10GBASE-T Ethernet, in which case there are no spare pairs and all power is delivered using the phantom technique.
   The original physical layer specified was 100BASE-TX Fast Ethernet. Since the end of 2006, Ethernet Powerlink with Gigabit Ethernet supported a transmission rate ten times higher (1,000 Mbit/s).
  
  Repeating hubs instead of switches within the Real-time domain is recommended to minimise delay and jitter. Ethernet Powerlink uses IAONA's Industrial Ethernet Planning and Installation Guide for clean cabling of industrial networks and both industrial Ethernet connectors 8P8C (commonly known as RJ45) and M12 are accepted.
  
  Section::::Data link layer.
   Section::::Medium frequency (100 kHz).:Transmitting radio programs.
  
  Sometimes PLC was used for transmitting radio programs over powerlines. When operated in the AM radio band, it is known as a carrier current system.
  
  Section::::High-frequency (≥ 1 MHz).
  
  High frequency communication may (re)use large portions of the radio spectrum for communication, or may use select (narrow) band(s), depending on the technology.
  
  Section::::Home networking (LAN).
   Although AC power wires are not designed for networking applications, power line communication (PLC) allows these wires to also be used to interconnect home computers, peripherals or other networked consumer products. The HomePlug protocol family was an early PLC technology. In December 2008, the ITU-T adopted Recommendation G.hn/G.9960 as the first worldwide standard for high-speed powerline communications. G.hn also specifies techniques for communications over the existing category 3 cable used by phones and coaxial cable used by cable television in the home.
   BULLET::::- Time-synchronisation of all nodes in the network with very high precision of sub-microseconds
  
  BULLET::::- Transmission of less timecritical data in a reserved asynchronous channel
  
  Modern implementations reach cycle-times of under 200 µs and a time-precision (jitter) of less than 1 µs.
  
  Section::::Standardization.
  
  Powerlink was standardized by the Ethernet Powerlink Standardization Group (EPSG) and founded in June 2003 as an independent association.
  
  Working groups focus on tasks like safety, technology, marketing, certification and end users. The EPSG cooperates with the standardization bodies and associations, like the CAN in Automation (CiA) Group and the IEC.
  
  Section::::Physical layer.
   Broadband over power line (BPL) is a system to transmit two-way data over existing AC MV (medium voltage) electrical distribution wiring, between transformers, and AC LV (low voltage) wiring between transformer and customer outlets (typically 110 to 240 V). This avoids the expense of a dedicated network of wires for data communication, and the expense of maintaining a dedicated network of antennas, radios and routers in wireless network.
   There are several common techniques for transmitting power over Ethernet cabling. Three of them have been standardized by IEEE 802.3 since 2003. These standards are known as "Alternative A", "Alternative B", and "4PPoE". For 10BASE-T and 100BASE-TX, only two of the four signal pairs in typical Cat 5 cable are used. "Alternative B" separates the data and the power conductors, making troubleshooting easier. It also makes full use of all four twisted pairs in a typical Cat 5 cable. The positive voltage runs along pins 4 and 5, and the negative along pins 7 and 8.
   Many powered devices have an auxiliary power connector for an optional external power supply. Depending on the design, some, none, or all of the device's power can be supplied from the auxiliary port, with the auxiliary port also sometimes acting as backup power in case PoE-supplied power fails.
  
  Section::::Power management features and integration.
   A phantom power technique is used to allow the powered pairs to also carry data. This permits its use not only with 10BASE-T and 100BASE-TX, which use only two of the four pairs in the cable, but also with 1000BASE-T (gigabit Ethernet), 2.5GBASE-T, 5GBASE-T, and 10GBASE-T which use all four pairs for data transmission. This is possible because all versions of Ethernet over twisted pair cable specify differential data transmission over each pair with transformer coupling; the DC supply and load connections can be made to the transformer center-taps at each end. Each pair thus operates in common mode as one side of the DC supply, so two pairs are required to complete the circuit. The polarity of the DC supply may be inverted by crossover cables; the powered device must operate with either pair: spare pairs 4–5 and 7–8 or data pairs 1–2 and 3–6. Polarity is defined by the standards on data pairs, and ambiguously implemented for spare pairs, with the use of a diode bridge.
   Medium voltage (MV) lines carry generally up to a few tens of kilovolts, over a few kilometres between the electricity distribution stations and pole-mounted transformers. Low voltage lines transmit a few hundred volts over a few hundreds of metres, usually from pole-mounted transformers into a home or business.
  
  Typically modem couplers embed data signals on to MV lines at the substation, with extractors at the LV distribution transformer feeding power into a group of buildings.
   In 2014, Cisco created another non-standard PoE implementation called Universal Power over Ethernet (UPOE). UPOE can use all 4 pairs, after negotiation, to supply up to 60 W.
  
  Section::::Non-standard implementations.:Linear Technology.
  
  A proprietary high-power development called LTPoE++ using a single CAT-5e Ethernet cable is capable of supplying varying levels at 38.7 W, 52.7 W, 70 W, and 90 W in addition to being backwards compatible with IEEE 802.3at.
  
  Section::::Non-standard implementations.:Microsemi.
  
  PowerDsine, acquired by Microsemi in 2007, has been selling midspan power injectors since 1999 with its proprietary "Power over LAN" solution. Several companies such as Polycom, 3Com, Lucent and Nortel utilize PowerDsine's Power over LAN.
   According to a comparative study conducted in a real world home-environment and published in the proceedings of the WMSCI 2008, the "PLC adapter from Intellon outperforms other PLC products and the IEEE802.11n/g for UDP and TCP throughput and HDTV streaming performance", and for the Internet Protocol Television (IPTV) "the of Homeplug AV is at least 18Mbps higher than that of IEEE 802.11 (g and n) because of improved design and the quasi-stationary channel characteristics of PLC".
  
  Section::::Standards.:Standards organizations.
   BULLET::::- IEEE 802.1Q (Dot1q) VLANs, trunking and -tagging.
  
  Section::::Product line.:5500 series.
   Ethernet on unshielded twisted-pair cables (UTP) began with StarLAN at 1 Mbit/s in the mid-1980s. In 1987 SynOptics introduced the first twisted-pair Ethernet at 10 Mbit/s in a star-wired cabling topology with a central hub, later called LattisNet. These evolved into 10BASE-T, which was designed for point-to-point links only, and all termination was built into the device. This changed repeaters from a specialist device used at the center of large networks to a device that every twisted pair-based network with more than two machines had to use. The tree structure that resulted from this made Ethernet networks easier to maintain by preventing most faults with one peer or its associated cable from affecting other devices on the network.
   100BASE-TX is the predominant form of Fast Ethernet, and runs over two wire-pairs inside a category 5 or above cable. Each network segment can have a maximum cabling distance of . One pair is used for each direction, providing full-duplex operation with 100 Mbit/s of throughput in each direction.
  