A wireless telephone (telefone sem fio) is an electronic telephone that comprises of a wireless handset and a base unit. Communication is carried out between the handset and the base utilizing radio waves. The wireless handset could be operated only within a set range from its base unit. The range of operation is generally within 100 meters. The base unit needs electricity to power it. Batteries are used to power the wireless handset. Placing the cordless handset in the cradle in the base unit recharges these batteries. A period of 12 to 24 hours is needed for recharging the batteries.
With features like cell handover, data transfer and international roaming (on a limited scale), the as soon as clear-cut line between mobile telephones and cordless telephones (telefone sem fio) has now been blended by the contemporary cordless telephone standards.
Frequency bands have been assigned in every country for cordless telephones (telefone sem fio). Advertisements by producers claiming that there is an improvement in audio range and quality with greater frequency are a typical sight. But that is not the case. Really, higher frequencies have been seen to demonstrate worse distribution in ideal case. There is also a tendency for the path loss to improve with greater frequencies. Locally diverse factors such as antenna quality, signal strength, the modulation technique becoming used and interference are more influential than other elements.
With Landline telephones working on a bandwidth of about three.6 kHz (a little fraction of the frequency that a human ear can interpret), the transport of audio is carried out with an audio quality that’s just enough for the parties to communicate one another. Because of this restriction in the style of the phone system itself, it isn’t possible to enhance the audio quality beyond a specific limit in cordless telephones.
Most of the good-quality cordless telephones (telefone sem fio) try transferring the audio signal with lowest possible interference and greatest possible range. Even the very best of the cordless telephones fail to match the audio quality that a top quality phone wired to a great telephone line provides.
Sidetone (echo of voice heard in the speaker of the receiver), disturbing constant background noise that’s because of the cordless program, and inability to obtain a full frequency response that’s available in a wired phone are few of the reasons for a not-so-good audio quality. Rare exceptions, clearly, always exist that sound incredibly similar to a wired telephone. However even these are regarded as as `fluke` by most industry standards.
Higher frequency is now being used in other house goods like the microwave oven, Baby monitor, Bluetooth, wireless LAN, etc. Thus, cordless telephones (telefone sem fio) utilizing greater frequency may face interference from signals from these devices.
Eavesdropping is really a constant security hazard for analog telephones. Any one with a radio scanner and within range can pick up these signals and listen to conversations. Modern digital technology is therefore being utilized to deal with this kind of illegal access.
DSS (Digital Spread Spectrum) makes use of frequency hopping, i.e. dispersing up of audio signal over a wider range in a pseudorandom fashion. DSS signal sounds like noise bursts to a radio scanner or any other analog receiver. This signal makes sense only to that base unit which has the same pseudorandom number generator as the cordless handset. Every time the cordless handset is returned to its cradle, a new distinctive generator is chosen from thousands of choices.
DSS generates a signal spread that leads to a kind of redundancy, which gives rise to improved signal-to-noise ratio. Additionally, it leads to increase in signal range and decreases interference susceptibility. It’s easier to make use of this kind of wide-bandwidth security option with higher frequency.