Cordless Telephones

Cordless Telephones were the precursors to the now almost ubiquitous and cheap cell phones. For those of you who have not done away with your fixed line phones, a cordless telephone gives you the ability to talk on the phone and simultaneously move about freely or multitask in the environs of your home.

Cordless telephones consist of a receiver or radio transmitter and a base unit. This base unit is attached to the phone jack through a standard fixed line phone connection. This base unit receives the incoming call as an electric signal through the phone line and it then converts this electric signal into a FM radio signal and broadcasts the signal. The receiver then converts the radio signal that it receives from the base unit into an electrical signal and cordless phone rings to alert you to your incoming call.

When you call someone using the handset of your cordless telephone, it converts your voice into another FM radio signal and transmits into the base unit which receives this signal and converts into an electric signal and sends it through the fixed phone line to the receiving party at the other end. The base unit and handset operate in tandem on a frequency known as duplex frequency so you are able talk and listen at the same time.

When you decide to buy a cordless telephone which is essentially a combination of a standard telephone and a radio transmitter you have to be cognizant of a few aspects of the technology that operates this cordless telephone. The first aspect is the range of the cordless phone. This range is actually the maximum distance between the handset and the base unit which allows the phone to function effectively as sound quality is affected by the range of a unit. Sound quality is also affected by other factors like walls and appliances and the manner in which the radio signal is transmitted.

Cordless also come in a wide range of frequencies and the frequency bandwidth also affects the price of a cordless phone. Phones with a lower frequency bandwidth are generally priced lower than those with higher frequency bandwith. Cordless phones which have a lower frequency bandwidth have additional security issues as their radio signals can be easily picked up by other cordless phones in the vicinity, baby monitors and radio scanners.

Moreover many low end cordless phones use analog technology rather than digital technology to operate. Analog signals are noisier and are also extremely vulnerable to interference which affects their sound quality. Cordless phones that use digital technology have generally better sound quality and are also more secure than analog cordless phones. In 1995 Digital Spread spectrum technology that spreads information in pieces over several frequencies was introduced for digital cordless telephones and now conversations conducted on digital cordless phones cannot be interfered with or listened too. All cordless phone handsets are also equipped with a rechargeable battery which may be a nickel-cadium, nickel-metal hydride or lithium battery.

A wide range of ordless telephones are produced by manufacturers like Panasonic, Uniden, Vtech etc. These cordless phones often come bundled with other features like answer machines and the ability to host two telephone lines as well.