DIGITAL SUBSCRIBER LINE ACCESS
Digital Subscriber Line (DSL) is a family of technologies that are used to transmit digital data communications of various media types over copper wire. It has been more than 20 years since the first market introduction of ADSL and HDSL as broadband access technologies for business and residential applications. Yet, recently DSL has gained a renewed life in industrial, transportation, traffic, and enterprise applications due to its robust performance, low cost of equipment, and the large installed base of copper wire.
Today ADSL2+, the latest version of classic ADSL, can achieve data rates up to 25Mbps downstream, 3 Mbps upstream over a single wire pair, and reach up to more than 22,000 feet with repeaters and extenders. ADSL2+ is capable of supporting applications for high-definition television, as well as telephone services (voice over IP), general Internet access, and data communications over a single wire-pair connection.
Adding fiber on the uplink enables the deployment of fiber-DSLAMs at the network “edge”, thereby optimizing the performance of the hybrid fiber/copper network using existing fiber and copper. A smart combination of copper/fiber deployments is providing operators with a timely and cost-effective solution while leveraging the past investments in installed copper loops to the largest extent possible.
In many cases, this level of performance is more than enough for applications in unserved and underserved areas which are still running sub-1Mbps rates and in the new IOT (Internet of Things) applications where lower speed data transmission for sensor parameters gathering is just what is needed or, in fact, is more than enough.
VDSL is a DSL technology providing data transmission faster than ADSL over a single pair of copper wires. VDSL is also capable of supporting applications such as CCTV, data communications, and general Internet access over a single connection. 20Mbps performance can be achieved in the 4000 foot range over copper.
The Second-generation systems in VDSL2 can provide data rates of 80 Mbit/s, and the maximum available bit rate achieved is less than 1000 feet. Built on global ITU and IEEE standards and decades of use, equipment providers, and carriers have gone beyond the “single-pair” concept of using one wire pair to achieve high data rates over bonded lines, while specialized modes of operation have extended reach far beyond the typical distance of copper technology.
Today G.SHDSL.bis, an alternate and enhanced form of classic HDSL, can achieve symmetrical data rates of 15 Mbps per copper pair or reach far beyond 22,000 feet. A growing number of industrial applications rely on G.SHDSL.bis as a robust long-reach communications technology. Examples are CCTV cameras, vending machines, public displays, traffic control, wired/wireless backhaul, industrial communications, and sense & control (IOT) applications. Eight pairs of copper wire can achieve over 110Mpbs symmetrically at 1000 feet or 50Mbps at 1 mile.
An important standard for DSL was produced by a working group of the Institute of Electrical and Electronics Engineers (IEEE) and became a part of the standard IEEE 802.3ah (EFM, Ethernet First Mile) in 2004. Later, this standard was included in IEEE standard 802.3, where it is named 2BASE-TL. Extreme Copper adheres to the 2BASE-TL standard in its G.SHDSL.bis and VDSL equipment.
The traditional business broadband access application profile is evolving. Often marketed as Metro Ethernet or EFM, SHDSL based services provide a tremendous value-add to deployed copper lines. Small businesses that may be out of fiber reach – like hotels, banks, offices or shops – can get state-of- the-art 100 Mbps symmetrical rates over bonded copper.
DSL technology goes even faster with it most recent additions: G.fast and G.vector. G.fast is a digital subscriber line (DSL) protocol standard for local loops shorter than 1500 feet, with performance targets between 150 Mbits and 1 Gbits, depending on loop length. G.fast is delivering speeds over 100 megabits at nearly 1500 feet and is capable of 300Mbps at 1000 feet thereby supplanting the need for fiber optics at the network edge.
Vectoring is a transmission method that employs the coordination of line signaling for the reduction of crosstalk levels and, thereby, performance improvement. G.vector is also known as ITU-T G.993.5. Vectoring is much like the headphones people have started to use increasingly on airplanes to reduce or cancel background/engine noise when listening to music or watching a movie. Vectoring calculates the interference between all wire pairs based on the actual signals and uses this information to cancel noise and remove crosstalk. The net gain is between 25% and 100%.
Extreme Copper offers modems and multiplexers to cover the rate and reach requirements suitable for deployment in temperature hardened outside plant applications. Extreme Copper is committed to enabling the best and the latest in copper technologies with the ultimate benefit of enabling necessary transmission speeds and minimizing infrastructure costs and unnecessary upgrades.