The address bar, originally known as URL (Universal Resources Locator) bar is a widget, which appears on the address bar beginning with http://. The http protocol indicates the web browser that the opening page is written in Hyper Text Markup Language and the accesses from World Wide Web. The file, which downloads from ftp server begins from ftp://. Besides these the file can also be accessed from the hard drive, because the web browser also works as a file manager. It begins with C:\ if the file is accessed from the hard drive.
DSL refers to Digital Subscriber Line, an all time on service used for subscribing internet through using standard telephone line connection, while DSL filter is a peripheral part of DSL service that requires sometimes for installing the DSL device. DSL filter, also known as micro filter is an analog low-pass filter device that installs on telephone and other analog device for preventing interference between analog devices and DSL service operating on the same line.
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