Leased lines are symmetric telecommunications lines that connect two different locations together. In the United Kingdom, lease lines are often referred to as Data Lines or Private Circuits. They do not have telephone numbers, but instead each of the sides of the line will be permanently connected to the other.

There are a number of different reasons for why leased lines could be useful, including;

- For telephone services

- Data services

- Internet services

While in many cases leased lines are finding themselves being replaced by metro Ethernet and DSL lines, they still do have a purpose in many applications.

Operating a lease line involves paying only an annual rental fee and no connectivity charges have to be paid in order to keep the leased line operating over time.

All that they really require is a fixed connection line from one place to another. The detail that makes leased lines a popular option for connecting data lines is the fact that they offer a twenty-four hour constant level of support and service, which is what most businesses require in order to operate smoothly.

This data line is dedicated to ensuring a fast and direct connection to a host server or internet server at all times.

Leased lines may be on the way out in many applications as other seemingly faster options take over, but that does not mean that they have been rendered completely obsolete.

In many business applications, leased lines still have a lot to offer companies who need dedicated communication means that are always available on a 24/7 basis, whenever they need them.

When a leased line is in place, different office buildings and other offices or resources can be connected together directly. This allows connections and data to be shared between them in a way that is quicker and more efficient than other connection means.

This can be extremely beneficial because it allows for an increase in the effectiveness and productivity of staff in both offices.

When different business locations are connected together in this particular way, it gives two separate offices or buildings the ability to link on a peer-to-peer basis for VOIP or Voice over IP, and it allows businesses to share services and data together with one another without increasing additional costs associated with other forms of data transmission, such as internet, fax and telephone.

Any business entity that relies heavily upon the communication with others at all times, twenty-four hours a day and seven days a week is going to benefit from what leased lines have to offer. They are both dedicated and uninterrupted in nature, which means that businesses can communicate between multiple buildings on a peer-to-peer basis without sacrificing quality of transmission or having to wait for a fax or telephone call to go through.

Leased lines are completely uninterrupted and produce service on a dedicated level at all times. This allows for businesses to interact within their own communication circles and networks, making leased lines a perfect option for many businesses.