ADSL mainly uses copper cabling and older technologies, while VDSL uses fiber optic components.
ADSL can reach up to 20Mbps (in terms of Telkom’s infrastructure, but the technology itself can handle higher speeds) and VDSL can reach up to 40Mbps (also limited by Telkom’s infrastructure).
Digital Subscriber Line (DSL) services provide individuals and businesses with low-cost, high-speed data transmission options. This is especially useful where wired Internet isn’t available.
In xDSL, the data is transmitted over copper wires using a local loop (connected to your existing telephone cable network). DSL is cheap and reliable.
Even though all xDSL technologies will degrade as distance increases, some kinds of DSL are better suited for specific distances and bandwidths.
HDSL (High-Bit-Rate DSL)
HDSL was standardized in 1994, using two pairs of 24 AWG wires to provide symmetric E1/T1 data transfer up to 3,557 meters. Its successors are HDSL2 and HDSL4, the latter using four pairs of wires instead of two.
SDSL (Symmetric DSL)
SDSL replaces HDSL as a two-line (single pair) symmetric DSL. SDSL is also called HDSL2 in ANSI.
SDSL is essentially the same as HDSL, with T1 speed (1.544 Mbps) within a range of up to 10,000 feet and is mainly for business users.
ADSL: Asymmetric DSL
ADSL transmission speeds range from 9 Mbps/640 kbps downlink/uplink rates within a relatively short distance to 1.544 Mbps/16 kbps (up to 18,000 feet). The former is more suitable for enterprises, the latter is more suitable for residential computing.
With ADSL’s large bandwidth, you can receive large files from a host or download multimedia files.
The unbalanced nature of ADSL and the various speed/distance options make it attractive for high-speed Internet access. As with most DSL services standardized by ANSI as T1.413, ADSL lets you pay for only the bandwidth you need.
SHDSL: Single-Pair, High-Speed Digital Subscriber Line
SHDSL is also called G.SHDSL, and its transmission speed is much faster than the old types of DSL. Compared to traditional voice modems, it can deliver faster transmission and internet connections over traditional copper wire telephone lines. Symmetric data rates make SHDSL a popular choice for businesses with PBX, private networks, web hosting, and other services.
SHDSL can be used effectively in corporate LAN applications. When connecting sites in a corporate campus, buildings and network equipment are usually more than an Ethernet segment can handle. Now you can use your existing copper network infrastructure to connect to a remote LAN at greater distances and faster speeds than previously possible.
This standard combines ADSL and SDSL functionality for communication over two or four copper wires with a rate of 192 kbps to 2.3 Mbps. As opposed to the old DSL service that aims to provide faster downstream speeds, SHDSL also specifies better upstream speeds. Using two to four copper wire pairs can achieve higher transmission rates from 384 kbps to 4.6 Mbps depending on the loop speed and noise.
In higher bandwidth symmetrical links, newer G.SHDSL devices support 10 Mbps rates for distances up to 1.3 miles (2 kilometers). Two-wire equipment can transmit up to 5.7 Mbps distances.
SHDSL (G.SHDSL) is the first DSL standard to be developed from scratch and approved by the ITU as a symmetrical digital subscriber line standard. The ITU recommendation G.991.2 specifies features of other DSL technologies, such as ADSL and SDS.
VDSL: Very-High-Bit-Rate DSL
VDSL, which was approved as a DSL service in 2001, offers up to 52 Mbps downstream and 16 Mbps upstream. Extenders for local networks offer 100-Mbps/60-Mbps speeds when communicating at distances as far as 500 feet (152.4 m) over a single voice-grade twisted pair. The VDSL broadband solution allows you to simultaneously transmit voice, data, and video, including HDTV, video on demand, and high-quality video conferencing. VDSL runs symmetrically or asymmetrically based on the application.
VDSL2: Very-High-Bit-Rate DSL 2
In 2006, VDSL2 was standardized, offering higher bandwidth (up to 100 Mbps) and symmetrical speed than VDSL, allowing it to use for longer-distance triple play services (data, video, and voice).Although VDSL2 supports upstream/downstream rates similar to VDSL, over longer distances, the speed won’t be as degraded as it would over ordinary VDSL equipment.
Fiber vs DSL Internet
DSL vs. Fiber If you have a fiber connection at home (FTTP or fiber to the house), then your maximum speed should be much faster than DSL. It depends on the physical characteristics of the fiber optic line and its advantages over copper. Any copper cable that exists in the chain from the exchange to the local will always be the bottleneck.
Why is that?
DSL transmits data via electrons over a copper cable. Copper is the world’s most conductive metal, so it’s great for transmitting signals with minimal loss. Fiber optic cables, however, transmit data with flashes of light. Fiber connections are obviously faster since they use light rather than electricity (close to, but not quite reaching, the speed of light since the flashes bounce repeatedly off of the inside of the cable rather than traveling directly down it unimpeded). This isn’t just faster, but also less likely to lose signal. Fibre optic lines have better throughput than copper because the signal gets to its endpoint sooner.
Factors that affect DSL speed
It’s not really your fault if you have a DSL connection. Speed will vary based on the distance between you and the cabinet and the cabinet’s distance from the local switch. This is because most Internet Exchange Points (IXPs) transmit data via fiber optic cables to a green cabinet close to your home. You might recognize this green cabinet on the side of the road. If you have a DSL connection, a copper telephone line will connect the cabinet to your home.
As a result, minimize the number of copper cables in your infrastructure to connect to the Internet, but enough copper cables are used to cause a bottleneck in the network.Data will enter the cabinet at high speeds, but will slow down significantly on its way to your home. Once there, any further slowdown will be caused by poor quality network equipment.
If your house is close to the cabinet, data will be transmitted over a shorter copper wire. This means (slightly unfairly) that households close to the cabinet have higher Internet speeds than households far from the cabinet, even if they use the same ISP.
In a lesser degree, your speed will also start to slow as you get farther from the IXP. But since the data is transported through fiber optic cables, it’s much more efficient, so it won’t be as noticeable.
DSL is much slower than VDSL. Therefore, DSL’s connection speed is much slower than VDSL.
With VDSL, you can get download speeds as high as 100 megabits per second (Mbps), whereas with DSL, you can get speeds as high as 3 Mbps. VDSL and DSL are limited to certain areas and speeds vary based on your proximity to the telephone exchange (the locked box the phone company keeps the switches for your neighborhood). You’ll have slower speeds the farther you are from the Central Office of your service provider.
VDSL is a newer, advanced technology, so it’s not available everywhere. ISPs are expanding their VDSL networks and making it more available to the public, but if you live in a remote area, you might not have access yet. DSL, however, is widely available from most Internet Service Providers.
In terms of both service and equipment costs, a standard DSL connection is much cheaper. You can get faster speeds with VDSL, but you may have to pay more for both the service and a compatible modem.