What is SDSL?
To understand SDSL, we must first understand the meaning of DSL. A Digital Subscriber Line (DSL) is a system of technology that uses phone lines to transmit data to the targeted destination to provide an internet connection. In doing this, people can surf the web and employees in businesses can perform the internet-related tasks that we as a modern society have become accustomed to.
How Does SDSL Work?
A pair of wires called the ‘local loop’ is used to transmit data digitally; initially, these wires were used for audio transmission, but using frequencies above allows for data transmission instead. Two circuits are integrated, one for upstream transmission and the other for downstream transmission, reducing the likelihood of collisions and delays.
One of the main subtypes of DSL is the Symmetric Digital Subscriber Line (SDSL). SDSL transmits the digital data with identical bandwidths for upstream and downstream transmission, indicating that the upload speeds from the device to the network, and download speeds from the network to the device, are the same. For companies, it is more important to use SDSL as there are equal needs for employees to download client information and upload company information, as one does not have more standing than the other. As the frequencies are the same, you cannot use a telephone whilst using the internet with an SDSL.
The process of installing SDSL is through the usage of different cables and a router. The socket on the wall must connect an SDSL cable (telephone cable made of copper) to the modem. The modem then uses an ethernet cable to connect to the device (a computer) and supply it with the internet.
SDSL VS. ADSL
1: Upload and download speeds
Essentially, a Symmetric Digital Subscriber Line and Asymmetric Digital Subscriber Line (ADSL) are opposite types of DSL. ADSL upstream and downstream data transmissions are of different bandwidths, so one has a faster speed than the other. This reflects that SDSL is more suited to businesses as they need equal speeds to upload and download data. ASDL may be more tailored towards homeowners that require rapid download speeds to surf the web and download files but do not necessarily upload as much information to the web as there is often no need, hence why downstream is prioritized.
2: Use of a telephone line
As aforementioned, SDSL installation is relatively straightforward as only internet access is needed. On the other hand, ADSL’s can utilize a telephone as well as an internet connection. This is because they use a different frequency to the telephone line, so both can be used simultaneously, thus why the installation process is a little more complex. Instead of the DSL cable connecting straight from the socket to the modem, a phone line splitter connects to the socket and then the DSL cable can be inserted to connect to the modem.
The phone line splitter acts as an intermediate so that the telephone line can also join to it and connect to the phone. This is the opposite of SDSL, which can only support data and analogue calls cannot be made nor received simultaneously. Nevertheless, it remains effective as the performance reaches its full potential for data usage without interfering with voice calling.
The cost of SDSL and ASDL is also similar, with SDSL being slightly more costly. It is difficult to compare because these DSL’s have different speeds, and so evaluation is not fair, but in general, both of these prices are extensively cheaper than fibre. DSL is more available geographically, whereas fibre optics are less accessible and, therefore, more costly due to their rarity; 98% of the UK can access DSL, whilst only around 6% can access fibre. Fibres also reach greater distances and are more reliable, whilst DSL’s degenerate the further the target destination is from the modem and provide lower bandwidths and, therefore, slower speeds.
The standardization of something is making it the most common and significantly more used than others. SDSL is considered more outdated than other alternatives and so-termed ‘proprietary’, suggesting it is less common and more exclusive, which may be why fewer people use it. Conversely, ASDL is standardized and used more in the current world by millions of homeowners that do not require the added advantage of equal upload and download speeds and do not need to pay more for this. Thi further amplifies why SDSL is more beneficial for small and medium businesses and not homeowners. Moreover, homeowners often use the telephone line, and the SDSL cannot provide this.
Even though SDSL is the preferred network for many businesses, this does not mean that many providers offer it. There are a limited number of companies in the UK that can provide SDSL, but they do exist. Unfortunately, prices vary and are not cheap.
Spitfire is a London-based company that has been around since 1988, with gross revenue of over £26 million. Their most popular package for SDSL includes 2Mbps upload and download speeds for £69 a month. This includes a free router and peak time priority with a two-year contract, explicitly targeted at low-value latency businesses and reduced packet loss. There are fewer delays and more successful and instant internet connections.
A more expensive provider of SDSL is Hotchilli, with the same 2Mbps speeds costing over £300 monthly, not including installation time. Due to the exclusivity of this network, costs are higher.
So… What is SDSL?
In conclusion, SDSL’s are optimal for businesses that prioritize uploading speeds to allow for faster backup and more satisfied customers. Whilst they cannot allow simultaneous phone usage, they can maximize the full potential of their internet connection and are less costly than fibre optics, proving useful for smaller companies.
Overall, the type of network needed for a business depends on why they use the internet and what type of services they provide. Therefore, for a company to choose an SDSL, they should deliberate on what type of upload and download speeds they require and whether they could manage without a simultaneous phone and internet connection.
Other useful links about business broadband
Ethernet First Mile Costs
EFM Business Broadband
Leased Lines – The Best Networks
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