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.
Understanding
Audio Normalling
