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What did we do before we had cordless phones? I remember being a teenager lying underneath the dining room table with the kitchen door closed, talking to a friend because that’s as far as the phone cord would reach. It really wasn’t that long ago, was it?

The original cordless phones date back to the late 1970’s when they were first introduced. The earliest models had limited range, poor sound quality and were a security risk as their signals were easily intercepted due to a limited number of channels. Through the 1980s and 90s the FCC (Federal Communications Commission) granted cordless phones increasingly wider ranges of radio frequencies to accommodate growth and provide greater range and security. For example, in 1986 cordless phones operated on a frequency range of 47 to 49 mHz and in 1990 they had a range of up to 900 mHz.

In 1994, the first digital cordless phones were produced and in 1995 DSS (digital spread spectrum) was introduced which increased the security of cordless phones by enabling phone conversations to be digitally spread out, which drastically reduced unwanted eavesdropping. Then, in 1998 the FCC granted cordless phones the frequency range of 2.4 gHz. One gigahertz (gHz), by the way, is equal to 1000 megahertz (mHz). As of 2003, cordless phones have a frequency range of up to 5.8 gHz.

How do cordless phones work, anyway? The base works like a regular phone, receiving an incoming call through the phone line. It then converts that signal into an FM radio signal and broadcasts that signal to the cordless handset which converts that signal into the sound you hear. A similar sequence converts what you say into the signal that is sent out to your caller. In fact, two frequencies operate simultaneously so you can talk and listen at the same time. There are now many options of cordless phones to choose from.

 

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