A distribution frame on one side of which main cable connect and on the other side of which lesser cable connect. An MDF may connect external lines and trunks from the public network on one side and internal cables on the other. In an end user environment, an MDF may connect lines and trunks from the public network on one side, or perhaps cables from a PBX, and on the other side connect internal cables connecting to intermediate distribution frames, terminal blocks, or directly to terminals within the customer premises. Short jumpers connect one side to the other. In a telecommunications environment, network trunks terminate on one side and local loop lines on the other. The MDF incorporates protectors for protection against power spikes and surges, and serves as a test point. See also distribution frame, frame, and IDF.
(1) (Main Distribution Frame) A wiring rack that connects outside lines with internal lines. It is used to connect public or private lines coming into the building to internal networks. In a telco central office (CO), the MDF is generally in close proximity to the telephone switch. See IDF, CDF and wiring rack.
(2) (Multiple Domain Facility) Hardware and microcode supplied by Amdahl that allows the running of multiple system images on a single processor complex. MDF was the first such implementation that did not depend on software such as VM/370 or VM/ESA.