Definition - What does Dedicated Line mean?
In IT, a dedicated line is a particular fiber-optic cable, twisted-pair cable line, coaxial cable or other physical cable line that is available at all times for a specific service. The opposite of a dedicated line is a shared line, where a single line can be temporarily used for more than one type of data transmission.
Dedicated lines are also known as non-switched lines.
Techopedia explains Dedicated Line
One of the best examples with issues around dedicated lines is the traditional use of telephone landlines by companies in the 1990s to offer dial-up internet service. As the internet started to become more popular, many households used the same telephone lines for telephone and internet services. This was an efficient use of services that cut down on household utility bills, but also presented a lot of problems with dropped calls, dropped internet connections, line noise and other issues.
Eventually, the majority of consumers chose to purchase telephone and internet services on entirely separate lines, to enjoy a dedicated service for each at any time of the day. Another example of shared lines becoming a problem is the shared use of telephone and fax lines, where voice callers tend to get annoying line noise upon connection.