Main Distribution Frame

Main Distribution Frame - Telephony/Broadband equipment. Termination point within the local Telephone exchange. All exchange equipment and any terminations to the local loop appear at the MDF, i.e. all copper pairs supplying Telephony/Broadband services are terminated here and distributed to their subsequent piece of equipment within the local Exchange e.g. DSLAM.

The most common kind of large MDF is a steel rack accessible from two sides. On one side, termination blocks are arranged horizontally at the front of rack shelves. Jumpers lie on the shelves and go through a steel hoop to run vertically to other termination blocks that are arranged vertically. By British custom the cables to the outside world are terminated on the horizontal side, and the indoors equipment on the vertical side. American usage is vice versa.

Sometimes the MDF is combined with other kinds of distribution frame in a CDF