Page 68 - NetWork-En-V3

One of the main drawbacks of this type of connection is the low data transfer rate,
which does not exceed the speed of the modem, typically 56 kilobits per second.
Additionally, the same telephone line cannot be used for making phone calls during
the internet connection.

11.2.2DSL (Digital Subscriber Line)
DSL (Digital Subscriber Line) utilizes the landline telephone network for internet
connectivity. Telephone cables are used to connect to a specific device in the central
office called DSLAM, which, in turn, connects to the internet service provider's
equipment using high-speed techniques for information transmission. DSL uses high
frequencies to transmit digital data for internet communication, leaving low
frequencies (audible frequencies) for regular telephone calls. This allows the phone
to be used for making calls while connected to the internet without interruptions.
This type supports speeds of up to 100 megabits per second within limited distances.
The speed decreases with the distance from the customer to the central office, and
the use of numerous connections and junctions in the connection cables can also
affect internet speed.

There are different types of DSL:
1. Asymmetric Digital Subscriber Line (ADSL):

In this type, the download speed to the user's device is higher than the speed for
uploading data from the user's device. It is the most common type for homes and
offices, where users receive more data than they send.
2. Symmetric Digital Subscriber Line (SDSL):
In SDSL, download speeds to the user's device are equal to upload speeds from
the user's device. This type is commonly used in companies and organizations
where sending and receiving data have equal importance.

61 Central Unit for Information Technology Training - Supreme Council of Universities © Intellectual Property Rights 2024