main distributing frame

main distributing frame

[′mān di′strib·yəd·iŋ ‚frām]
(electricity)
Frame which terminates the permanent outside lines entering the central office building on one side and the subscriber-line multiple cabling, trunk multiple cabling, and so on, used for associating an outside line with any desired terminal on the other side; it usually carries the control-office protective devices, and functions as a test point between line and office. Also known as main frame.
References in periodicals archive ?
The project will begin with conversion of about 2,500 main distributing frame (MDF) diagrams which detail the termination of outside plant cable pairs at Bell Canada's switching centers.