Atkinson Dynamics AD-27 Specifikace stáhnout pdf (Strana 6)

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Figure 3.

ISOLATEDBALANCED/UNBALANCEDLINES:

The audio signals are transmitted over a wire pair using balanced

line technology. This means each wire carries a signal that is opposite

inpolarityoftheother.Attheinputoftheintercomisanisolated

balanced line transformer. This transformer subtracts the two signals

from each other providing an output free of noise generated onto the

wires by some other noise source such as a motor or light ﬁxture near

the wires.

The isolation provided by the transformer means that the grounds

of the units are not connected by the audio lines. Therefore, ground

loops and other problems caused by non-isolated systems are avoided.

The polarity of the audio lines between the + and - signal terminals

need not be maintained.

 Ashieldedcablecanbeusedininstallationswhereextreme

problems from interference are suspected. The shield should always

be connected to the ground of only one of the intercoms. Connecting

the shield to ground at both ends will cause ground currents to travel

through the shield which could cause hum in the system.

 Thereareseveraldiagramsinthebackofthemanualtoaidin

wiring intercoms together. The wiring diagram section illustrates bal-

anced and unbalanced line interconnection along with how a shielded

audiocablecanbeused.(Seegures5through12.)Italsoillustrates

290A3078

24VDC IN/OUT

GROUND

CLASS I WIRING CLASS II WIRING

REMOTE CONTROL

REMOTE SPEAKER

EXT CALL

CONTACT

COMMON

PHASE

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Atkinson Dynamics AD-27 Specifikace Strana 6