How does DSL work? Digital Subscriber Line (DSL) provides high-speed digital modem technology via a conventional telephone line. DSL uses signal frequencies above those used by voice or fax, so the DSL signal does not interfere with telephone conversations or faxes. When a DSL filter is connected to your phone jack, its function is to split the data (Internet) traffic from voice (phone) traffic, and route them separately. Voice traffic goes to the phone or the fax machine, while your computer traffic goes through the Verizon DSL modem and to your computer, thus allowing you to use both simultaneously.

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