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In `F33f`_`[telecommunications`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Telecommunications]`_`f, a `!distribution frame`! is a passive device which terminates cables, allowing arbitrary interconnections to be made.

For example, the `F33f`_`[main distribution frame`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Main_distribution_frame]`_`f (MDF) located at a `F33f`_`[telephone central office`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Telephone_exchange]`_`f terminates the cables leading to `F33f`_`[subscribers`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Subscribers]`_`f on the one hand, and cables leading to active equipment (such as DSLAMs and `F33f`_`[telephone switches`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Telephone_switch]`_`f) on the other. Service is provided to a `F33f`_`[subscriber`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Subscriber]`_`f by manually wiring a `F33f`_`[twisted pair`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Twisted_pair]`_`f (called a jumper wire) between the telephone line and the relevant `F33f`_`[DSL`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=DSL]`_`f or `F33f`_`[POTS`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Plain_old_telephone_service]`_`f line circuit.

In `F33f`_`[broadcast engineering`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Broadcast_engineering]`_`f, a distribution frame is a location within an apparatus room through which all signals (`F33f`_`[audio`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Sound]`_`f, video, or data) pass, with the ability to arbitrarily route and connect sources and destinations between studios and other internal and external points. Connections can either be `F33f`_`[soldered`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Solder]`_`f, or made using terminal blocks. Because the frame may carry live broadcast signals, it may be considered part of the `F33f`_`[airchain`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Airchain]`_`f.

In `F33f`_`[data communication`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Data_communication]`_`f, a `!building distribution frame`! (`!BDF`!) houses data switches, etc.

>>Contents

• `F0af`_`[Types`#types]`_`f

• `F0af`_`[Modernization`#modernization]`_`f

• `F0af`_`[See also`#see-also]`_`f

• `F0af`_`[References`#references]`_`f

• `F0af`_`[External links`#external-links]`_`f

-─

>>Types

Distribution frames for specific types of signals often have specific initialisms:

• DDF `!–`! `F33f`_`[digital`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Digital_data]`_`f distribution frame

• IDF `!–`! `F33f`_`[Intermediate distribution frame`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Intermediate_distribution_frame]`_`f

• MDF `!–`! `F33f`_`[Main distribution frame`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Main_distribution_frame]`_`f

• ODF or OFDF `!–`! `F33f`_`[optical fiber`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Optical_fiber]`_`f distribution frame`:cite-ref-1[`F5bf`_`[1`#cite-note-1]`_`f]

• VDF `!–`! `F33f`_`[voice`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Voice]`_`f distribution frame

>>Modernization

Distribution frames may grow to extremely large sizes. In major installations, audio distribution frames can have as many as 10,000 incoming and outgoing separate copper wires (`F33f`_`[balanced audio`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Balanced_audio]`_`f signals require two wires plus `F33f`_`[earth ground`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Earth_ground]`_`f for each signal). Telephone signals do not use a separate earth ground wire, but some urban `F33f`_`[exchanges`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Telephone_exchange]`_`f have about 250,000 wires on their MDF. Installing and rewiring these jumpers is a labour-intensive task, leading to attempts in the industry to devise so-called active distribution frames or `F33f`_`[Automated Main Distribution Frames`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Automated_Main_Distribution_Frame]`_`f. The principal issues which stand in the way of their widespread adoption are cost and reliability.

Newer `F33f`_`[digital`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Digital_data]`_`f `F33f`_`[mixing consoles`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Mixing_console]`_`f can act as control points for a distribution frame or `F33f`_`[router`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Router_(computing)]`_`f, which can handle audio from multiple studios (even for multiple co-located `F33f`_`[radio`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Radio_station]`_`f or `F33f`_`[TV`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Television_station]`_`f stations) at the same time. Multiple smaller frames, such as one for each studio, can be linked together with fibre-optics (which also helps eliminate `F33f`_`[ground loops`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Ground_loop_(electricity)]`_`f), or with `F33f`_`[gigabit Ethernet`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Gigabit_Ethernet]`_`f. This has the advantage of not having to route dozens of feeds through walls (and sometimes floors and ceilings) to a single point.

>>See also

• `F33f`_`[66 block`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=66_block]`_`f – Table used to physically connect phone lines

• `F33f`_`[Patch panel`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Patch_panel]`_`f – Device featuring a number of jacks for connecting and routing circuits

• `F33f`_`[Splicebox`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Splicebox]`_`f

• `F33f`_`[Wiring closet`:/page/wikibook/entry.mu`zim=wikipedia_en_all_nopic_2025-08.zim|entry_path=Wiring_closet]`_`f

>>References

`:cite-note-1`!1.`! `F0af`_`[↑`#cite-ref-1]`_`f US 7142765, "High Density Optical Fiber Distribution Frame"

>>External links

• Media related to Distribution frames at Wikimedia Commons

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