Main distribution frame arrangement

摘要

A main distribution frame (MDF) for a telephone exchange has terminal fields each with terminals for connection to subscribers' lines and sockets for plug-in line circuit units of the types appropriate to the lines served. The sockets are in blocks with for each such block a back plane carrying common wiring for that block. The back planes each provide access to a TOM link to the switching equipment. There are a number of sets of blocks each of which sets includes blocks one above the other in a column, with the inter-column and inter-block gaps available for cable runs and straps. This gives a "corrugated" structure which facilitates screening. The links can be of the fibre-optic type.