Ethernet over coax – commercial converters

Nowadays it is possible to buy passive and active device to run Ethernet over Coax – some products support data transfer over larger distances then you can get on regular Cat5. The passive converters are typically limited to 100 Mbps maximum speeds up to 100-200 meters distance maximum.

If you need faster speed or longer distance, you need to use active converters. In essence, the idea is to creates a wired Internet home network, but without the headache of drilling holes or running wires.

There aremany different types of active converters on the market with different specifications. There are many company specific products and there are also products based on some agreed standards. Some standards to get Ethernet-like speed over coaxial cables are HomePNA, MoCA and G.Hn just to mention few available to normal user applications. Cable TV operators use cable modems (usually DOCSIS standard) to run IP data over their cable TV networks.

Most EoC technologies are designed to operate in frequency bands above 1 GHz, which is the upper bound of television signals and for systems designed to operate in North America using the SCTE 55-1 and SCTE 55-2 CATV transmission systems, as well as in most of Europe and portions of Asia.

Commercial passive converters for one 75 ohm coax

There are commercially made passive Ethernet to 75 ohm coax cable converters designed for video surveillance applications. Video surveillance systems have traditionally used 75 ohms coaxial cable to carry analogue (and later in some cases digital) video signal from camera to surveillance center. When IP based digital cameras have become popular, there has been interest to run Ethernet signal over single 75 ohm coaxial cable from surveillance center to the IP camera.

There are many different products marketed for this, some are active devices and some are completely passive devices. For passively adapting 10/100M Ethernet to single 75 ohm coaxial cable, there are product like Monoline Coax Balun – Male BNC to RJ45 jack 10BaseT – 75 Ohm – Each and IP Passive Extender Ethernet Over Coax 1-CH, IP Network to Coaxial Transmitter IP Network Converter Fit CCTV Camera UTP RG59/ RJ45 4-Wired 1236 Cable No. BNC Video Balun Only Fit POE Camera System.

Those are designed to be used for 10 and 100 Mbps speeds only, and do not support any higher speed (like 1G). Dahua also makes converters for the same application.

There are also active adapters designed for IP camera applications in mind for example Ethernet Extender and PoE injector all in one device and Coax to Ethernet Extenders Transmit Ethernet data over Coax.

HomePNA

The HomePNA Alliance is an incorporated non-profit industry association of companies that develops and standardizes technology for home networking over the existing coaxial cables and telephone wiring within homes, so new wires do not need to be installed. It was formerly the Home Phoneline Networking Alliance, also known as HPNA. The original protocols used balanced pair telephone wire. HomePNA 3.1 added Ethernet over coax. HomePNA uses frequency-division multiplexing (FDM), which uses different frequencies for voice and data on the same wires without interfering with each other. A standard phone line has enough room to support voice, high-speed DSL and a landline phone.

HomePNA does not manufacture products. HomePNA creates industry specifications which it then standardizes under the International Telecommunication Union (ITU) standards body. The HomePNA Alliance, tests implementations, and certifies products if they pass.

The HomePNA versions:
HomePNA 1.0 technology was developed by Tut Systems in the 1990s.
HomePNA 2.0 was developed by Epigram and was approved by the ITU as Recommendations G.9951, G.9952 and G.9953.
HomePNA 3.0 was developed by Broadcom (which had purchased Epigram) and Coppergate Communications and was approved by the ITU as Recommendation G.9954 in February 2005.
HomePNA 3.1 was developed by Coppergate Communications[3] and was approved by the ITU as Recommendation G.9954 in January 2007. The original protocols used balanced pair telephone wire. HomePNA 3.1 added Ethernet over coax.

HomePNA 3.1 uses frequencies above those used for digital subscriber line and analog voice calls over phone wires and below those used for broadcast and direct broadcast satellite TV over coax, so it can coexist with those services on the same wires. HomePNA over coax operates between 12 MHz and 44 MHz; the higher start frequency avoids interfering with other services that might be operating over the coax such as VDSL2.

In March 2009, HomePNA announced a liaison agreement with the HomeGrid Forum to promote the ITU-T G.hn wired home networking standard. In May 2013 the HomePNA alliance merged with the HomeGrid Forum. So nowadays HomePNA and G.hn can perform similar functions.

Long-term product-lifecycle support for HomePNA seems to be somewhat questionable.

G.hn

G.hn is a specification for home networking with data rates up to 2 Gbit/s and operation over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. A single G.hn semiconductor device is able to network over any of the supported home wire types. G.hn was developed under the International Telecommunication Union’s Telecommunication Standardization sector (the ITU-T) and promoted by the HomeGrid Forum and several other organizations. ITU-T Recommendation (the ITU’s term for standard) G.9960, which received approval on October 9, 2009. The G.hn spectrum depends on the medium.

The G.hn2 specification was developed by the International Telecommunication Union (ITU). The physical layer is capable of supporting 10 Gbps over coax. It utilizes mesh technology, supports encryption on the cable, and supports distances up to 100 meters.

G.hn specifies a single physical layer based on fast Fourier transform (FFT) orthogonal frequency-division multiplexing (OFDM) modulation and low-density parity-check code (LDPC) forward error correction (FEC) code. G.hn includes the capability to notch specific frequency bands to avoid interference with amateur radio bands and other licensed radio services. G.hn includes mechanisms to avoid interference with legacy home networking technologies[6] and also with other wireline systems such as VDSL2 or other types of DSL used to access the home. Although most elements of G.hn are common for all three media supported by the standard (power lines, phone lines and coaxial cable), G.hn includes media-specific optimizations for each media: OFDM Carrier Spacing is 195.31 kHz in coaxial, 48.82 kHz in phone lines, 24.41 kHz in power lines. G.hn uses OFDM to achieve gross speeds up to 1 Gbit/s. The 5-200 MHz range handles upstream and downstream traffic using an Orthogonal Frequency-Division Multiplexing (OFDM) encoding. Transmission rates of 1 Gbit/s at application level are possible with coax cables up to approx. 800 meters, via phone line up to approx. 250 meters (MIMO) or approx. 150 meters (SISO). Connectivity up to approx. 1800 meters (coax) or 800 meters (phoneline) is possible.

G.hn is an access technology for operators looking to simplify their access network and reduce their costs with an Ethernet-like technology. The ITU-T G.9960 G.hn Wave-2 standard leverages the existing telephone wiring (UTP, CAT-3 or CAT 5/5e) or RG-6/RG-59 coax cabling (each coax port serves up to 16 subscribers) to deliver a gigabit Internet service to each apartment inside a Multi-Dwelling Unit (MDU) or Multi-Tenant Unit (MTU) without the cost, complexity, and delays, associated with in-building fiber installation. Each G.hn subscriber port supports up to 1.7 Gbps of dynamically allocated bandwidth for near-symmetrical gigabit services.

When operating over Coax, G.hn uses baseband spectrum from 5-200 MHz. Unlike Data Over Cable Service Interface Specifications (DOCSIS), G.hn dynamically allocates each tone to carry either upstream or downstream traffic to reflect the demand from the subscribers, achieving gigabit speeds in both directions.

Like the DOCSIS High-Split, G.hn allows CATV channels starting at 258 MHz. The very important difference and benefit of G.hn is that it does not use any spectrum that overlaps with the CATV content. It is very easy to overlay the G.hn and CATV signals over the same coaxial cabling using standard splitters-combiners. G.hn optimizes the spectrum use on coaxial cabling to achieve superior bandwidth to DOCSIS in the upstream and downstream directions.

The ITU-T G.hn standard provides high-speed (up to 1 Gigabit/s) local area networking over existing home wires, including coaxial cable, power lines and phone lines. It defines an Application Protocol Convergence (APC) layer for encapsulation standard 802.3 Ethernet frames into G.hn MAC Service Data Units (MSDUs). Because G.hn can operate over wires including AC and DC power lines, it can provide the communication infrastructure required for smart grid applications.

When G.hn devices has RJ11 connector for data communication and such device needs to be connected to coaxial cable, a suitable baluns is needed. Lea Networks Balun Media Converter, 75ohm Coax to 100ohm Twisted Pair, G.Fast & G.hn can convert balanced twisted pair signal to unbalanced 75Ω coaxial signal.

There is also a new faster variation G.hn2 coming. G.hn2 supports up to 10 Gbps over coax. Note that in order to achieve 10 Gbps, the entire coax RF spectrum is utilized so therefore the coax cannot be used with any other signals.

The Multimedia over Coax Alliance

MoCA Access™. provides managed services for symmetrical multi-gigabit, low-latency access over coax. Point-to-Multipoint Coax Connectivity. In short, MoCA delivers a reliable, wired home network connection over a home’s existing coaxial wiring, providing lower latency and near Gigabit speeds. With MoCA everyone in the house can stream 4K movies at the same time and enjoy super-fast speeds without lag or downtime.. MoCA promises to turn your Existing Cable Wiring into a 1 Gbps Super Highway. MoCA signals will not interfere with your existing cable modem and vice-versa, your cable modem will not interfere with your MoCA network. Using coaxial wiring replaces the need for installing Ethernet cabling throughout your home.

(MoCA) standard allows people to use TV-grade coaxial cable to carry modern ethernet traffic. You can get a MoCA bridge to use the cable from the wired ethernet. Some routers or TV based devices like TiVO have a MoCA bridge built in. If you don’t already have MoCA capable devices, you’d need to get a pair of MoCA bridges to connect devices over cable. There are MoCA adapters for creating Ethernet bridges over coaxial cable (while passing through CATV/OTA TV/CCTV/DOCSIS signals).

There has been several versions of MoCA. MoCA 1.0 was approved in 2006, MoCA 1.1 in April 2010, MoCA 2.0 in June 2010, and MoCA 2.5 in April 2016. The most recently released version of the standard, MoCA 2.5, supports speeds of up to 2.5 Gb/s. The Alliance currently has 45 members including pay TV operators, OEMs, CE manufacturers and IC vendors.

The technology started with Passive MoCA (with no active electrical components on integrated circuits) supports 10 Mbps. That was short lived experiment.

The first version of the standard, MoCA 1.0, was ratified in 2006 and supports transmission speeds of up to 135 Mb/s. MoCA 1.1 provides 175 Mbit/s net throughputs (275 Mbit/s PHY rate) and operates in the 500 to 1500 MHz frequency range. MoCA 2.0 offers actual throughputs (MAC rate) up to 1 Gbps. Operating frequency range is 500 to 1650 MHz. Packet error rate is 1 packet error in 100 million. In March 2017, SCTE/ISBE society and MoCA consortium began creating a new “standards operational practice” (SCTE 235) to provide MoCA 2.0 with DOCSIS 3.1 interoperability. Interoperability is necessary because both MoCA 2.0 and DOCSIS 3.1 may operate in the frequency range above 1 GHz. MoCA can operate up to 1500 1675 MHz.MoCA frequencies are 1125-1675MHz. Over-the-air TV frequencies only go up to 692 MHz.

MoCA 2.5 (introduced April 13, 2016) offers actual data rates up to 2.5 Gbit/s, continues to be backward compatible with MoCA 2.0 and MoCA 1.1. The current MoCA 2.5 Gbps devices utilize frequencies above 1 GHz to achieve 2.5 Gbps, thereby allowing normal cable signals below 1 GHz. Bonded MoCA 2.5 supports up to 2.5 Gbps in throughput, but as of early 2019, most adapters available use bonded MoCA 2.0 (1 Gbps) or lower. The largest vendors are Actiontec, TiVo (OEMing Actiontec), Teleste, and Yitong.

The MoCA 3.0 standard has been released and increases the maximum throughput to 10 Gbps. MoCA 3.0 specification utilizes mesh technology, supports encryption on the cable, and supports distances up to 100 meters. Note that in order to achieve 10 Gbps, the entire coax RF spectrum is utilized so therefore the coax cannot be used with any other signals. If less than 10 Gbps is utilized, then the RF spectrum could be shared. MoCA 3.0 is backwards compatible with MoCA 2.0 and MoCA 2.5.

Modern MoCA with active electronics is a mesh technology and you can have up to 16 nodes through your house. Most MoCA bridges work in the D band, above 1 GHz so they are compatible with cable TV signals. You can get bridges that support 1 Gbps (MoCA 2.0 profile C bonded channels). MoCA adapters multiplex and diplex Ethernet and any passed-through signals in the 7-42 MHz and 54-875 MHz range (such as TV, cable modem, etc.), so a minimum of 2 adapters are required to book-end the signals. With a MoCA adapter at point A and another at point Z, the network functions as though an Ethernet cable connected the 2 points. But again, it takes two to tango. (You can add 16 total adapters in many cases, but that merits a discussion about MoCA splitters and point-of-entry filters.) You also need to be concerned with port-to-port isolation. With satellite splitters, the port-to-port isolation in the MoCA bandwidth is a minimum 24dB, while with MoCA splitters, it is a maximum 25dB. With MoCA, you want the signals to be able to go from one port to another without too much obstruction.

Due to the isolation requirements for MoCA and DOCSIS to minimize interference, a two-box solution is preferred for HFC. This separates the home network from the outside plant. Additionally, this allows for the same home network architecture regardless of whether HFC or fiber is used for the access to the home.

MoCA videos:

Teardown of an ActionTec WCB3000N MoCA v1.1 Cable to Ethernet adapter
https://www.youtube.com/watch?v=6ye1xwWR3bM

Hacking a super cheap MoCA adapter to make it do my bidding! Ethernet over coaxial cable.
https://www.youtube.com/watch?v=hiNSjBW_UtA

How to Install a MoCA-Enabled Cable Modem to Improve Network Performance
https://www.youtube.com/watch?v=x0cgXY3Q_Zc

MoCA Setup and Testing
https://www.youtube.com/watch?v=t0h_Zag7cpU

Double your Home Network Speed – Motorola MOCA Adapter
https://www.youtube.com/watch?v=i9WVH-2BjDA

How to Turbo-Charge your Wi-Fi(R) with a Wire
https://www.youtube.com/watch?v=BMO7B0pzYjQ

DOCSIS

Coaxial Ports are used by cable operators for modems based on DOCSIS standard.Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable television (CATV) system. It is used by many cable television operators to provide cable Internet access over their existing hybrid fiber-coaxial (HFC) infrastructure.

The base definition of DOCSIS 3.1 allocates the 5-42 MHz range to upstream traffic, resulting in “up to” 100 Mbps of shared bandwidth across all subscribers on a Cable Modem Termination System (CMTS) port. DOCSIS vendors have recently introduced solutions to provide more upstream bandwidth by extending the spectrum for the upstream bands.

DOCSIS is technology designed for cable TV operators in mind. A DOCSIS modems are designed to always communicates with equipment that cable TV has in it’s network. You can’t make a home network with two DOCSIS cable modems only, you need the cable TV operator always “in the loop”.



Cable television (CATV) networks are governed by a set of DOCSIS standards that place hard limits on bandwidth and data rates. The latest version of the DOCSIS standard, DOCSIS 3.1 was released in October 2013. DOCSIS 3.1 increases the bandwidth and data throughput available in CATV networks by up to 10 Gbps downstream and 1 Gbps upstream.

Isemag article says on network engineering: A DOCSIS network is engineered to serve an average of 150 subscribers on the premises in which the peak use per subscriber is well below 5 Mbps downstream and below 350 Kbps (not Mbps) upstream. To me those numbers on data rate seem to be quite low, and maybe reflect to the old days then users did not need high bandwidth Internet.

Technologies for 10G networking

In 2019, the cable industry announced the 10G Initiative to bring 10 Gbps into customers’ homes. Once it gets to customers’ homes, how will it be distributed throughout the home?

There are four candidates that can meet 10 Gbps in a consumer home environment: Ethernet 10GBase-T, MoCA 3.0, hn2 (coax) and Wi-Fi 7.


For 10G delivery within the home, it is suggested that Ethernet 10GBase-T, MoCA 3.0, or G.hn2 (coax) be used for hardwire delivery of the 10 Gbps data within the home to Wi-Fi 7 access points (APs).

Cable operators need to start thinking about how they will distribute the 10 Gbps signal through the home network once 10 Gbps technology is available and offered as a service. If they desire to use Ethernet, then the use of coax in homes should be switched over to Ethernet. If they desire to utilize the existing wiring and continue to use coax, then they need to plan on utilizing MoCA 3.0 or G.hn2, and to start deploying it as soon as the desired technology is available. When Wi-Fi 7 is used for communication, multiple APs will be required to provide the desired speeds throughout the premises.

1 Comment

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