Digital subscriber line

When study data need to be transferred to the Study Director at regular intervals (typically after each application, sampling, and shipment), the e-mail and attachment transfer rate is critical. In isolated field sites, with poor telephone tine quality, the upload can take hours. This is also a problem when downloading software updates. Also, the upload/download time may be a problem when it ties up the only telephone tine or fax tine. If available in the area, the use of a faster form, such as cable modem or digital subscriber line (DSL), is preferable. Since telephone tine quality is a common problem, it would be best if software developers sent updates on CD-ROMs. 

DSL 256Kbps to Digital Subscriber Line. Shares existing phone wires with voice service. 

The Internet. According to the United Nations International Telecommunication Union (ITU), the number of Internet users across the world met the two billion mark in January 2011. Much like standard telephone service, the capacity, ease, and speed to the Internet has been greatly increased by the replacement of phone-based modem systems, cable modems, and digital subscriber line (DSL) by fiber-optics wired systems. Although fiber-optic connections directly to homes in the United States are not available in all areas, some companies use fiber-optic systems down major networking lines and then split to traditional copper wiring for houses. 

E-mail. To receive e-mail, a computer must be connected to the Internet. Connection can be made by coaxial cable or a satellite, as would be the case from a cruise ship. Most often, however, the computer is connected to a telephone line, and digital subscriber line (DSL) technology is used. So that the telephone can be used at the same time as the computer, a DSL circuit using high frequencies is used for the... 

DSL (digital subscriber line) was developed to deliver video over copper lines, for video-on-demand services designed to compete with cable television, but it proved to be more popular for providing fast-speed Internet services. 

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