Difference between Cable and DSL modems

The easy way of getting high speed internet is through modems. There are two modems that are readily available in the market in cheaper price. These two categories are, Cable and DSL Modems. In this article, we are going to discuss about the difference between cable and DSL modems. The DSL modem uses copper wires because of which it is a high speeding barrier.

Cable modems are those modems which were used in past time but now they have partially taken off the market. The DSL modems are the Digital Subscriber Line. It falls in the family of technologies that are used to transmit any kind of digital frequency over telephone lines. Whereas the cable modem is the normal one where in you have a router and there is a LAN wire which is connected to it router and this router emit the waves as WIFI so that the people or the users can connect and make use of it.

The head end connects to the end user via a network of fibre-optic and coax cables. The TV channels and Internet channels are frequency multiplexed and modulated on to the main fibre-optic cable for transport out to distribution hubs that rejuvenate the signals over longer cable runs. From the one or more distribution hubs, the signal travels to multiple optical nodes located in various city or suburban neighbourhoods. In a typical arrangement, a single fibre is split to dish up four fibre optical nodes. Most fibre nodes provide up to 500 to 550 homes. With this agreement, each fibre serves up to 2000 or 2200 homes, though not all houses passed have a cable modem or facility.

Almost all the TV signals and the Internet’s data are transmitted in a range of 6-MHz broad channels. Just because a coax cable has a bandwidth as wide as 850 MHz to 1 GHz, the structure can accommodate from 140 to 170 downstream channels of 6 MHz each. The Television signals or the Internet data are modulated on the carriers in each channel. There are also some upstream channels that allow the consumer to transmit data back to the head end. This communication takes place in 6-MHz channels as well that inhabit the cable spectrum from 5 MHz to 40 MHz or in a number of systems it is up to 65 MHz.

We can also say that, in an older cable TV systems, individual modulators add the video to the channel carriers that are linearly mixed to form the composite signal for transmission over the cable. Modern cable TV systems are beginning to use direct digital synthesis of the composite signal for transmission. The digital video signals are fed to an ASIC or FPGA, where an inverse FFT and other techniques implement the QAM modulation and up conversion. A fast RF DAC develops the final composite analogue signal for transmission on the cable.

All the Users who use this technology do not usually get the full download speeds mentioned above. It is because of the coax line in a bus shared by many homes, the data speed is separated up amongst those who are using the relation. A single and lone on its own user will get the full speed but with multiple users each will get a proportionally slower connection.

It is that the unique DSL system was initially designed to produce data rates of about 1.5 Mbps to 8 Mbps downstream from the respective telephone company to the subscriber and a lower charge upstream. Almost every internet access involves more of the downloading and less of the uploading of data. This results in the design is referred to as uneven DSL or ADSL. Most of the DSL formats are irregular, though there are DSL variations that deliver the same rates in both the directions.

All the definite data rate depends not only on the intonation method used but also on the number of sub channels used and, of course, the reserve between the central office or DSLAM and the CPE. All the noise is another limiting factor. The DSL modem can get used to to noise environment by examining the spectrum and blocking channels with too much noise content. This reduces the speed but maintains the linkage with precise data.

Therefore these are some differences that are between these two modems, you can go through it and make the choice of your liking.

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