Editing Distribution frame

{{Short description|Place at which telecommunications cables interconnect}}
{{primary sources|date=July 2008}}
[[File:Distribution-frame-0a-messy.jpg|thumb|right|150px|Unshielded twisted pair (copper) and optical fiber distribution frame]]
[[File:Optical-fiber-distribution-frame-0a.jpg|thumb|right|150px|An optical fiber distribution frame]]
In [[telecommunications]], a '''distribution frame''' is a passive device which terminates cables, allowing arbitrary interconnections to be made.

For example, the '''Main Distribution Frame''' (MDF) located at a [[telephone exchange|telephone central office]] terminates the cables leading to [[subscribers]] on the one hand, and cables leading to active equipment (such as DSLAMs and [[telephone switch]]es) on the other. Service is provided to a [[subscriber]] by manually wiring a [[twisted pair]] (called a jumper wire) between the telephone line and the relevant [[DSL]] or [[Plain old telephone service|POTS]] line circuit.

In [[broadcast engineering]], a '''distribution frame''' is a location within an apparatus room through which all signals ([[Sound|audio]], 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 [[Solder|soldered]], or made using terminal blocks. Because the frame may carry live broadcast signals, it may be considered part of the [[airchain]].

In [[data communication]], a '''building distribution frame''' (BDF) houses data switches, etc.

==Types==
Distribution frames for specific types of signals often have specific [[initialism]]s:
* DDF '''–''' [[Digital data|digital]] distribution frame
* IDF '''–''' [[Intermediate distribution frame]]
* MDF '''–''' [[Main distribution frame]]
* ODF or OFDF '''–''' [[optical fiber]] distribution frame<ref>[https://web.archive.org/web/20160315003309/http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=7142765 US patent 7,142,765]—''High Density Optical Fiber Distribution Frame''</ref>
* VDF '''–''' [[voice]] 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 ([[balanced audio]] signals require two wires plus [[earth ground]] for each signal). Telephone signals do not use a separate earth ground wire, but some urban [[Telephone exchange|exchanges]] have about 250,000 wires on their [[Main distribution frame|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 [[Automated Main Distribution Frame]]s. The principal issues which stand in the way of their widespread adoption are cost and reliability.

Newer [[Digital data|digital]] [[mixing console]]s can act as control points for a distribution frame or [[router (computing)|router]], which can handle audio from multiple studios (even for multiple co-located [[radio station|radio]] or [[television station|TV]] 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 [[ground loop (electricity)|ground loops]]), or with [[gigabit Ethernet]].  This has the advantage of not having to route dozens of feeds through [[wall]]s (and sometimes [[floor]]s and [[ceiling]]s) to a single point.

==See also==
*[[Intermediate distribution frame]]
*[[Main distribution frame]]
*[[Patch panel]]
*[[Splicebox]]
*[[Wiring closet]]

==References==
{{reflist}}
{{Commonscat|Distribution frames}}
{{Authority control}}
[[Category:Broadcast engineering]]
[[Category:Telephony equipment]]