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| a fixed-line telephone system |
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[ 2011-5-11 10:23:00 | By: klmn064 ] |
Telephone headsets connect to a fixed-line telephone system. A telephone headset functions by
replacing the handset of a telephone.Discount beats
by dre All telephone headsets come in a standard 4P4C commonly called an RJ-9 connector.
For older models of telephones, the headset microphone impedance is different from that of the
original handset, requiring a telephone amplifier for the telephone headset. A telephone
amplifier provides basic pin alignment similar to a telephone headset adaptor, but it also
offers sound Discount dre beatsamplification
for the microphone as well as the loudspeakers. Most models of telephone amplifiers offer volume
control for loudspeaker as well as microphone, mute function and headset switching. Telephone
amplifiers are powered by batteries or AC adaptors.
The moving coil driver, more commonly referred to as a "dynamic" driver is the most common type
used in headphones. The operating principle consists of a stationary magnetic element affixed to
the frame of the headphone which sets up a static magnetic field. The magnetic element in
headphones is typically composed of ferrite or neodymium. The diaphragm, typically fabricated
from lightweight,headphones high stiffness to
mass ratio cellulose, polymer, carbon material, or the like, is attached to a coil of wire which
is immersed in the static magnetic field of the stationary magnet. The diaphragm is actuated by
the attached voice coil, when an audio current is passed through the coil. The alternating
magnetic field produced by the current through the coil reacts against the static magnetic field
in turn, causing the coil and attached diaphragm to move the air, thus producing sound. Modern
moving-coil headphone drivers are derived from microphone capsule technology.
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