PB-48 PATCH BAY SYSTEM
4
A patch bays jacks can be configured in four ways: Full-Normalled, Half-
Normalled, Non-Normalled and Multed.
Both the PB-48 and PB-48D are shipped as half-normalled patch bays. That
means each of their 24 vertical jack pairs are factory-set so the upper rear jack is
normally connected to the lower rear jack. The signal flow through the jacks on
the front panel is such that inserting a plug in the top jack on the front does not
break the normal connection between the rear panel jacks, but provides a tap on
its circuit to send a signal to two devices simultaneously. However, inserting a plug
into the lower front jack does break the signal flow, allowing the insertion of a
device, such as a signal processor, into the loop.
Half Normalled
As mentioned above, each vertical pair of upper and lower jacks on the PB-
48s rear panel is connected internally, and the signal flows through both of them.
The original setup of your equipment is retained, in that two devices are connected
without the use of any front panel patch cords. As shown in Figure 1, you can
connect one tape output to one of the PB-48s rear panel upper jacks, and connect
an input channel on a mixing board to the lower rear panel jack. The signal will
flow from the tape output to the mixer input without requiring a patch cord. All of
the rear panel jacks will function in this manner when there is no patch cord plugged
into the corresponding lower front panel jack.
Note: For simplicity, these diagrams
show mono plugs and jacks with only one normal link connecting a vertical pair,
but the jacks are actually TRS types with two links. Two are needed to connect
both the tip and ring contacts, to allow the use of balanced lines. The switch in the
bottom front jack is a double-pole type which switches both links simultaneously.
In a half-normalled patch bay such as the PB-48, each lower front panel jack
has an internal switch. When one end of a patch cord is inserted into the upper
front panel jack, the switch on the lower front panel jack remains closed, as shown
in Figure 2. The signal from the upper rear panel jack continues to flow to the lower
rear panel jack as it does in Figure 1, but it can also be simultaneously routed to
Figure 2
Figure 1
All manuals and user guides at all-guides.com
