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A naked DSL (a.k.a. standalone or dry loop DSL) is a digital subscriber line (DSL) without a PSTN (analogue telephony) service — or the associated dial tone. In other words, only a standalone DSL Internet service is provided on the local loop. == Comparison of Regular and Naked DSL (Standalone DSL)== In Regular DSL, data transmission is carried on inaudible high frequencies on a standard POTS Plain Old Telephone Service telephone line. The original idea was to leverage existing telephone lines for high speed data communication. DSL and telephone service can coexist on the same phone line and do not interfere with each other. From the Telco's point of view, DSL gives them the ability to sell the same telephone line twice, to the same customer. It is an idea that benefits the telco (who makes more money) and the customer (who gets a high speed data connection without the need for installation of expensive new cables.) Naked DSL is the same as standard DSL, except that there is no voice service. Telephone service is not required for DSL to operate correctly. The primary advantage of Naked DSL is financial: the customer saves the expense of a phone line, which they may not need. In terms of equipment, physical setup and speed, there is no difference between Naked DSL and Regular DSL. They are identical, except for the absence of dial tone. Telco Response to standalone DSL has generally been hostile. In the United States AT&T allows Standalone DSL for its own customers, but only very reluctantly, and it blocks third parties from providing Standalone DSL over AT&T telephone lines unless those customers also purchase AT&T branded voice services. Verizon stopped permitting Standalone DSL for its own customers in 2014, but some third parties such as Brand X Internet do still offer it. Verizon's own customers are required to buy Verizon branded voice services in order to purchase any kind of DSL. In regular DSL, a cable runs from the telephone switch to a piece of equipment called a Plain Old Telephone Service (POTS) splitter. This splitter separates the DSL and voice bands. Thus the customer will have a dial tone, which allows them to use the telephone line as a regular land line while they are using it to access the Internet on their computer. A cable carrying both services runs from the splitter to the cable head, where it continues on to the customer on outside plant. (See DSLAM.) In naked DSL, there is no cable from the telephone switch to the POTS splitter. Thus there is no dial tone on the line. However, the customer could still use the line for regular telephone service through Voice over Internet Protocol (VoIP) or a Competitive Local Exchange Carrier (CLEC) instead of the Incumbent Local Exchange Carrier (ILEC). Naked ADSL2 and ADSL2+ provisioned with "all digital mode" Annex I or Annex J can achieve additional 256 kbit/s of upstream data rate. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Naked DSL」の詳細全文を読む スポンサード リンク
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