A main-distribution-frame network is a telecom system that uses an MDF panel, as opposed to a patch panel, to connect complementary communications networks via flexible jumper cables. A facility's MDF panel usually takes a signal from outside and distributes it to the internal switching networks.
An MDF network has numerous advantages over older switching models. A large MDF panel is comparatively easy to service and repair, it allows finely regulated communication between networks, and it serves as a convenient test point for determining the overall system integrity. Automated switching methods have reduced the need for the large electromechanical switches common during the 20th century.