ADSL'S Technological blur

ADSL is abbreviation of Asymmetric digital Subscriber Line, one technology which memungkinan high speed data is transferred through telephone wire. ADSL enables to accept data until speed 1.5 9Mbps (downstream's speed) and transfers data at a speed 16 640Kbps (upstream's speed). ADSL divides frequency of thread that utilized by assumption a large part Internet user will more a lot of...

ADSL

Short for asymmetric digital subscriber line, a new technology that allows more data to be sent over existing copper telephone lines (POTS). ADSL supports data rates of from 1.5 to 9 Mbps when receiving data (known as the downstream rate) and from 16 to 640 Kbps when sending data (known as the upstream rate). ADSL requires a special ADSL modem. ADSL is growing in popularity as more...

Asymmetric digital subscriber line (ADSL)

Asymmetric digital subscriber line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call.[1] A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service...

Explanation

The distinguishing characteristic of ADSL over other forms of DSL is that the volume of data flow is greater in one direction than the other, i.e. it is asymmetric. Providers usually market ADSL as a service for consumers to connect to the Internet in a relatively passive mode: able to use the higher speed direction for the "download" from the Internet but not needing to run servers that...

On the wire

Currently, most ADSL communication is full-duplex. Full-duplex ADSL communication is usually achieved on a wire pair by either frequency-division duplex (FDD), echo-cancelling duplex (ECD), or time-division duplexing (TDD). FDD uses two separate frequency bands, referred to as the upstream and downstream bands. The upstream band is used...

Modulation

ADSL initially existed in two flavours (similar to VDSL), namely CAP and DMT. CAP was the de facto standard for ADSL deployments up until 1996, deployed in 90 percent of ADSL installs at the time. However, DMT was chosen for the first ITU-T ADSL standards, G.992.1 and G.992.2 (also called G.dmt and G.lite respectively). Therefore all modern installations of ADSL are based on the DMT modulation...

ADSL standards

Frequency spectrum of a modem on a ADSL line. Standard name Common name Downstream rate Upstream rate Approved in ANSI T1.413-1998 Issue 2 ADSL 8 Mbit/s 1.0 Mbit/s 1998 ITU G.992.1 ADSL (G.DMT) 12 Mbit/s 1.3 Mbit/s 1999-07 ITU G.992.1 Annex A ADSL over POTS 12 Mbit/s 1.3 Mbit/s ITU G.992.1 Annex B ADSL over ISDN 12...

Installation issues

Due to the way it uses the frequency spectrum, ADSL deployment presents some issues. It is necessary to install appropriate frequency filters at the customer's premises, to avoid interference with the voice service, while at the same time taking care to keep a clean signal level for the ADSL connection. In the early days of DSL, installation required a technician to visit the premises....