Knowledge Cordless Telephone

A cordless phone or a mobile phone is a phone with a cordless handset that communicates via radio waves with a base station connected to a fixed telephone line, usually within a limited range of its base station (which was the crib sets). The base station is the headquarters of the subscriber, and attaches to the telephone network the same way as a wired phone. The base station on subscriber premises is what differentiates a cordless phone to a mobile phone. Current cordless telephone standards, like PHS and DECT, have blurred the line cutting, a clear distinction between cordless phones and cell phones through the transfer of cells, several advanced features such as data transfer and also to a limited extent, international roaming . In these models, the base stations are operated by a mobile network operator and business users to subscribe to the service.

Unlike a standard telephone, a cordless phone needs power to power the base station. The wireless handset is powered by a rechargeable battery that is charged when the unit is in its cradle.

In 1980, a number of manufacturers, including Sony, offers wireless phones for the consumer market. Typically, they used a base station that is connected to a phone line and a telephone with a microphone, speaker, keyboard and telescopic antenna. The device contains a rechargeable battery in general, the basic unit was powered by household current, usually through a wall wart. The base includes a charging station, which was generally a form of charger wire, upon which the unit when not in use. Some cordless phones now uses two rechargeable AA or AAA batteries instead of more expensive traditional phone batteries ownership.

Cordless phones became commercially viable in the United States, only with the breaking of the monopoly Bell System in the land-line telephone service in 1984. Before the separation, all the phones were made by Western Electric and was rented to the customer. Losses In 1980, several companies entered the market for wireless: VTech, Uniden, Philips, Panasonic and Gigaset. They advertise many new features, some provided by telephone and more provided by the network.

Cordless Phone Frequencies

In the United States, seven bands have been assigned by the Federal Communications Commission for uses that include cordless phones. These are: 

* 1.7 MHz (1.64 MHz to 1.78 MHz and up to 5 channels, AM System)

* 43-50 MHz (Base: 43,72-46,97 MHz, tel: 48 , 76-49,99 MHz, assigned in 1986 to 10 channels and 25 channels, FM System) 

* 900 MHz (902-928 MHz) (allocated in 1990) 

* 1.9 GHz (1880-1900 MHz) (DECT communication systems used to Outside the United States) 

* 1.9 GHz (1920-1930 MHz) (developed in 1993 and assigned United States in October 2005) 

* 2.4 GHz (allocated in 1998) 

* 5.8 GHz (allocated in 2003 because of overcrowding in the range 2.4 GHz).

Almost all phones sold in the United States the use of 900 MHz, 1.9 GHz, 2.4 GHz or 5.8 GHz, although the legacy phones can still be used in higher age groups. There is no specific requirement for any particular mode of transport in 900, 1.9, 2.4 and 5.8, but in practice, almost all the most recent 900 MHz phones are inexpensive analog models with digital assets, such as FHSS and DSSS for usually available only at higher frequencies.

Some cordless phones advertised as 5.8 GHz actually transmit from base of 5.8 GHz and the mobile phone to transmit at 2.4 GHz or 900 MHz to conserve battery life inside the phone. The new allocated 1.9 GHz is used by the popular DECT phone standard and is considered more secure than other common frequencies.