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Normal & Half Normal Connections

Normalling refers to a specific wiring pattern (within a patchbay) that creates a path from one piece
of equipment to another without the use of a patchcord.

Patchbays include vertical sets of jacks that are mounted in a panel. In a normalled bay, each set of jacks have an internal connection between them (the top jack is connected to the bottom jack). Typically, the upper jack represents a signal output while the lower jack represents a signal input. With the patch bay left as it is (no patch cord inserted) the signal will flow from some output (top jack) to some input (bottom jack) in its normal fashion. When a patchcord is inserted to the top jack, it pushes one of the contacts aside, breaks the connection to that normalled input, and the output can be routed elsewhere. If a patchcord is inserted into the bottom jack, that normalled connection is broken and the patched signal (from a different output) can be fed to that input. 

In a half normalled patchbay, inserting a patchcord into the bottom jack breaks the normal but inserting one in the top jack does not. Because of this, one output can be connected to two inputs in a 'Y' type fashion.

Note:

It's not always acceptable to normal two plugs in a pair together.  Many pieces of gear (outboard gear for example), do not have a signal normalled to their points simply because there is no place for them.  Typically they would only be patched when needed.  If this gear and cassette decks, for example, were  were normalled, their inputs would be directly connected to their outputs when not patched elsewhere.  This could damage equipment

Dan Collins

Sales Engineer


   

  

ADC Patchbays

 

Understanding Audio Normalling
Normalling creates a default circuit through the patch panel to connect equipment together in the arrangement you normally or most frequently use. When you plug in a patch cord, you break this "normal" circuit and create a temporary new circuit. Pro Patch lets you select from a variety of normalling options.

   
  Normals Strapped (fully normalled)
  In a fully normalled configuration, the normals of each jack in the top row are internally strapped to the normals of the jack below it with the tip (T), ring (R), and sleeve (S) contacts brought out to the rear panel terminations. At the rear panel, equipment is wired to the two jacks, creating a normal circuit. To break this normal connection, you insert a patch cord into either jack.
   
  Half-Normalled
  In a half normalled configuration, the normals of the bottom jack are internally wired to the tip (T) and ring (R) connections of the to jack, and the tip, ring, and sleeve of both jacks are brought out to the rear terminations, creating a normal circuit. Inserting a plug into the top jack monitors the circuit without breaking it, and inserting a plug into the bottom jack breaks the circuit.
   
  No Normals
  A panel without normals has jacks that are open (no normal connection) until patched. When the patch cord is inserted, the signal flows through the cord and jack to or from the equipment connected to the jack at the rear termination No normal patch panels require looping plugs (u-links) or patch cords to complete the circuit.
   
  Normals Out
  In this configuration normals are brought out to the rear terminations where you can strap them as you want them. Note that you cannot change the normalling on panels with internal normals because normalling is done at the jacks. Select the normals out option if you need the ability to change normals.
   
  Sleeve Normals Out
  Sleeve normals out are the same as normals out except that a sleeve normal is switched inside the jack in addition to tip and ring normals. The sleeve normal is also brought out and is typically used for a ground connection. Making it switchable allows grounds for different functions to be separated to prevent ground loops that produce audio hum.
   
  Bussed Grounds
  In a bussed grounds configuration the ground connections of all jacks are brought out to the rear terminations and connected together. This provides a common ground for all jacks.

 
 
 
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