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Home Automation in Cloud-Based IoT
Published in Fadi Al-Turjman, The Cloud in IoT-enabled Spaces, 2019
Fadi Al-Turjman, Mohamad Sanwal
Digital subscriber line (DSL) technology is a wired communication medium that transfers data through the standard telephone lines at a frequency range of 4,000 Hz to 4 MHz depending on the type. The technology is approved by ITU G.992 recommendations. Three different types of this technology are commonly used: Asymmetric DSL (ADSL) offers a data rate of 1–8 Mbps with a maximum coverage of 5 km, high bit-rate DSL (HDSL) provides a data rate of 2 Mbps for a distance of 3.6 km, and very high-speed DSL (VDSL) can cover a maximum of 1.5 km distance but with relatively higher data rates that range between 15 and 100 Mbps. Unlike ADSL, the key feature associated with HDSL type is the symmetricity of downstream and upstream where it processes an equal data packet in both directions. DSL technologies can be integrated with IoT-based smart homes’ HANs and NANs. They can also provide access to rural areas and distribution and transmission substations.
The Future of Broadband Access
Published in Marcus K. Weldon, The Future X Network, 2018
The first broadband access service in the 1990s delivered rates ranging from a few hundred kb/s to a couple of Mb/s, which was a huge improvement compared to the tens of kb/s possible with a dial-up modem. Access capacity for DSL services delivered over twisted pair grew exponentially over the years, as shown in figure 3 (Maes 2015). Every new technological step enabled providers to deliver new services: asymmetric digital subscriber line (ADSL) was well suited for early web browsing on the internet, while very-high-bit-rate DSL (VDSL) was ideal for the delivery of video. While many believed that this would be the endpoint for DSL, the introduction of vectoring (Oksman, Schenck et al 2010) to cancel crosstalk between twisted pairs in the same bundle, which was inspired by interference cancellation techniques used in wireless communication, resulted in a significant improvement of the signal quality over VDSL. This gave providers the ability to support up to 100 Mb/s and multiple simultaneous streams of high-definition content per household. Where multiple pairs to the home were available, it was also possible to combine their capacity through bonding across pairs, which combined the capacity of the pairs into a single, logical, high-capacity transmission link. And this remarkable technological feat — delivering near-fiber-like speeds over copper loops that were designed for 56 kb/s and, in some cases, were approaching 100 years of age — continues today, thereby turning copper into commercial gold.
Understanding Broadband over Power Lines
Published in Gilbert Held, Understanding Broadband over Power Line, 2016
Concerning data transmission capability, DSL’s maximum achievable data rate decreases as the distance between the subscriber’s premises and the serving telephone office increases. Currently the maximum data rate obtainable through the use of the most popular type of DSL service, ADSL, is approximately 1.5 Mbps. However, the average DSL user more than likely experiences a maximum data transmission rate of approximately 1 Mbps. It should also be noted that some telephone companies offer a low-cost data transmission DSL service that is typically limited to 256 kbps. Although approximately five times faster than dial-up PSTN usage, the so-called “DSL Lite” represents the lowest high-speed Internet access technology.
The Changing Face of Public Broadcasting in India
Published in IETE Journal of Education, 2023
The internet connection is provided to a telephone subscriber with the help of an ADSL (Asymmetric Digital Subscriber Line) connection to the telephone exchange, or else, a fiber optic modem. The data bit-stream is decoded in a proprietary set-top box (STB), to recover video as well as audio information. The STB needs to have adequate processing power to accomplish signal reconstruction as well as data decompression. The user watches only one program at a time, but the link to the telephone exchange is two way. The user can select any program by sending a command via the remote control. The service provider, in turn, directs the user selected data to the particular STB. The OTT service operates as an interface layer, for the pay channel, and facilitates selection from a variety of video recordings as well as live programs.