| A cordless telephone is an electronic
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| | and greatest possible range. Even the best
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| telephone that comprises of a wireless
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| | of the cordless telephones fail to match
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| handset and a base unit. Communication is
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| | the audio quality that a high quality
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| carried out between the handset and the
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| | phone wired to a good telephone line
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| base using radio waves. The wireless
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| | provides.
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| handset can be operated only within a
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| | Sidetone (echo of voice heard in the
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| fixed range from its base unit. The range
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| | speaker of the receiver), disturbing
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| of operation is generally within 100
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| | constant background noise that is due to
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| meters. The base unit needs electricity to
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| | the cordless system, and inability to
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| power it. Batteries are used to power the
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| | obtain a full frequency response that is
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| cordless handset. Placing the cordless
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| | available in a wired phone are few of the
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| handset in the cradle in the base unit
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| | reasons for a not-so-good audio quality.
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| recharges these batteries. A period of 12
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| | Rare exceptions, obviously, always exist
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| to 24 hours is required for recharging the
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| | that sound unbelievably similar to a wired
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| batteries.
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| | telephone. But even these are considered
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| With features like cell handover, data
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| | as `fluke` by most industry standards.
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| transfer and international roaming (on a
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| | Higher frequency is now being used in
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| limited scale), the once clear-cut line
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| | other home products like the microwave
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| between mobile telephones and cordless
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| | oven, Baby monitor, Bluetooth, wireless
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| telephones has now been blended by the
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| | LAN, etc. Thus, cordless telephones using
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| modern cordless telephone standards.
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| | higher frequency may face interference
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| Frequency bands have been assigned in each
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| | from signals from these devices.
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| country for cordless telephones.
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| | Eavesdropping is a constant security
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| Advertisements by manufacturers claiming
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| | threat for analog telephones. Any one with
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| that there is an improvement in audio
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| | a radio scanner and within range can pick
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| range and quality with higher frequency
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| | up these signals and listen to
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| are a common sight. But that is not the
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| | conversations. Modern digital technology
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| case. Actually, higher frequencies have
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| | is thus being used to take care of this
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| been seen to exhibit worse propagation in
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| | kind of unauthorized access.
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| ideal case. There is also a tendency for
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| | DSS (Digital Spread Spectrum) makes use of
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| the path loss to increase with higher
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| | frequency hopping, i.e. spreading up of
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| frequencies. Locally varying factors such
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| | audio signal over a wider range in a
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| as antenna quality, signal strength, the
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| | pseudorandom fashion. DSS signal sounds
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| modulation method being used and
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| | like noise bursts to a radio scanner or
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| interference are more influential than
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| | any other analog receiver. This signal
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| other factors.
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| | makes sense only to that base unit which
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| With Landline telephones working on a
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| | has the same pseudorandom number generator
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| bandwidth of about 3.6 kHz (a small
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| | as the cordless handset. Each time the
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| fraction of the frequency that a human ear
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| | cordless handset is returned to its
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| can interpret), the transfer of audio is
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| | cradle, a new unique generator is chosen
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| carried out with an audio quality that is
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| | from thousands of options.
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| just enough for the parties to communicate
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| | DSS generates a signal spread that leads
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| each other. Because of this limitation in
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| | to a kind of redundancy, which gives rise
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| the design of the phone system itself, it
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| | to increased signal-to-noise ratio. It
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| is not possible to improve the audio
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| | also leads to increase in signal range and
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| quality beyond a particular limit in
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| | decreases interference susceptibility. It
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| cordless telephones.
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| | is easier to use this kind of
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| Most of the good-quality cordless
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| | wide-bandwidth security option with higher
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| telephones try transferring the audio
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| | frequency.
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| signal with lowest possible interference
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