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Related to ASDL: ADSL, ASL


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(1) (Domain-Specific Language) See special-purpose language.

(2) (Digital Subscriber Line) A technology that increases the digital capacity of ordinary telephone lines (the local loops) into the home or office for Internet and TV service. Depending on the DSL version, speed is based on the distance between the customer and telco central office or telephone junction box.

DSL provides "always-on" operation. At the central office, DSL traffic is aggregated in a unit called the DSL Access Multiplexor (DSLAM) and forwarded to the appropriate ISP or data network. DSL arrived in the late 1990s with more version alphabet soup than most any other new transmission technology. See PPPoA and PPPoE.

Asymmetric: Fast Down - Slow Up

ADSL - (Asymmetric DSL)
ADSL shares ordinary telephone lines by using higher frequencies than human speech. To eliminate interference, the first DSL deployments required a technician from the phone company to install a splitter that divided the line into separate DSL and phone lines. Subsequent splitterless versions (known as G.Lite, Universal ADSL and ADSL Lite) eliminated the support visit but require the user to plug filters into every phone outlet.

ADSL is available in two modulation schemes: Discrete Multitone (DMT) or Carrierless Amplitude Phase (CAP). See CDSL, G.shdsl, ATU-C and ATU-R.

ADSL Transmission
The higher frequencies of DSL have to be filtered out for regular telephones, answering and fax machines.

The Filter
Low-pass DSL filters split the line between phone and DSL modem. When DSL is installed, every telephone and answering machine must plug into the filter.

RADSL (Rate Adaptive DSL)
RADSL is a version of ADSL that adjusts speeds based on signal quality. Many ADSL technologies are actually RADSL.

VDSL/VHDSL (Very High Bit Rate DSL)
VDSL is used as the final drop from a fiber optic junction point to nearby customers. VDSL lets an apartment or office complex obtain high-bandwidth services using their existing copper wires without having to replace them with optical fibers. Like ADSL, VDSL can share the line with the telephone.

Whereas VDSL achieves 50 Mbps transmission speed at 1,000 feet, VDSL2 extended the length of the path to 3,300 feet and delivers 100 Mbps at 1,600 feet. See Gfast.

Symmetric - Same Speed Both Ways

HDSL (High Bit Rate DSL)
HDSL provides T1 transmission over copper wires without the additional provisioning required for setting up T1 circuits, such as bridged tap removal and repeater installation. HDSL requires two cable pairs up to 12,000 feet, while HDSL-2 requires only one cable pair and spans 18,000 feet. HDSL does not allow line sharing with analog phones.

SDSL (Symmetric DSL)
SDSL is an HDSL variation that is rate adaptive, uses one cable pair and is offered in speeds from 144 Kbps to 1.5 Mbps. Like HDSL, SDSL does not share lines with analog phones.

IDSL is a slightly faster basic BRI ISDN service. It uses the 16 Kbps "D" channel for data rather than call setup to achieve 144 Kbps instead of 128 Kbps. It also offers the longest distance of 26,000 feet. Unlike standard ISDN, IDSL does not support analog phones, and signals are not switched through the telephone network. Since IDSL uses the same 2B1Q line coding as ISDN, ISDN customers can use existing BRI terminal adapters and routers. See ISDN.

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References in periodicals archive ?
The key differentiators that accelerate ASDL's time to value are:
We report on a 44-year-old female patient with Alport syndrome and diffuse leiomyomatosis (ASDL) who was treated by a multidisciplinary team of specialists.
Do I still have to pay BT telephone line rental fees if I get ASDL?
ASDL, with its price-fixed, unlimited usage, is now available in major cities.
The ASDL is a method of archiving digital information by merging many libraries with different digital data types into one large system accessible by all users.
More and more people are moving to cable modem and ASDL connections to the Internet.
ASDL offers faster transmission (1.5 megabps), but is limited by the distance of the customer from the central facility.
On the other hand, Dell, Cisco and US West's announcement is about delivering ASDL services today, albeit restricted to those customers who sign up to US West's MegaBit service.
Within the next 12 months, you'll be able to choose among cable modems, ASDL, and who knows what other technology for fast residential connection.
He also describes a promising new technology called asymmetric digital subscriber line (ASDL), which "allows for the simultaneous transmission of compressed video, data, and voice signals over a single copper telephone line" (p.
In 6:1 YLKA : BKA = tlk' `vegetable', the proper ideogram is presumably the first word, Aramaic yrq , while the second word may be taken to be the New Persian word, of Arabic origin, baqla(t), introduced as a gloss in order to elucidate the meaning of the lemma.(15) And in 9:3 ASDL (or the like) = sgl `lion', several scholars have suggested a derivation from Arabic asad + the phonetic complement -ar, as in ABYtl = ptl `father'.(16) This explanation is difficult.
Dimitri Mavris is the Boeing Professor of Advanced Aerospace Systems Analysis at the Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, and the director of its Aerospace Systems Design Laboratory (ASDL).