subject: The Technology And History Behind Cordless Telephones [print this page] Radio technology is something that is quite commonly found in a variety of household appliances including the microwave, the baby monitor, wireless Internet routers, and the cordless telephone. Although the telephone was first born in 1876 - when Alexander Graham Bell first spoke those famous words Mr Watson come here I want to see you - it was not until 1965 when an erstwhile jazz singer called Teri Paul, who must have seen the benefits of being able to move freely with a wireless handset, came up with the cordless telephone.
In the beginning the wireless technology that supported the cordless telephone was only able to operate on low frequencies. This meant that it was susceptible to interference from other technology that was transmitting radio waves. However, it did not take too long before the cordless telephone was adapted to operate on higher frequencies; these newer models where not only free of interference but also were capable of transmitting signals across larger distances too.
The technology that is found in the traditional telephone and the corded telephone is quite similar, however there are some differences. A traditional landline telephone relies on acoustics to transmit the analogue signal back and forth between the caller and receiver. In this model the hook connects the user to a phone network and the sound is converted through a microphone and speaker. In addition to this there is also a dial and bell for dialling and receiving calls, on most modern equivalents this is replaced with an electric keypad and a ringtone. The key difference between a corded telephone and a cordless one is that the cordless telephone transmits the signal from the hand set to the base using radio waves, whereas the corded telephone obviously uses a wire.
A cordless phone takes the sound signals and converts them into radio waves with frequencies; this is done using something called quartz crystals. These signals are then broadcast through an antenna and put through an amplifier. A two-way frequency is used so that the user can both speak and listen, and when the phone rings a signal is sent to both the base and the hand set in case the two are not in the same place. Modern cordless phones have a number of new features including the useful caller ID, speed dial, SMS messaging, illuminated keypads and a variety of different ring tones. There are even models that are able to detect when it is night time and then adjust their volume accordingly.
