History of Cordless Phones

Cordless phones made its appearance during 1980. The earliest cordless phones that operated at a frequency of 27 MHz had certain problems. They faced some of the problems such as limited range, poor sound quality, noisy and static. Poor security is another problem they faced. Hence, people could easily intercept signals from another cordless phone because of the limited number of channels.

With an aim to improve such interference problem and reduce the power needed to run the cordless phones, the Federal Communications Commission (FCC) granted the frequency range of 47-49 MHz for cordless phones in 1986. Granting a greater frequency range allowed cordless phones to have less interference and need less power to run. But, still the cordless phones had the problems such as limited range and poor sound quality.

The FCC then granted the frequency range of 900 MHz for cordless phones in 1990. This higher frequency range allowed people to enjoy cordless phones having better qualities. The cordless phones operated at the frequency range of 900 MHz were found to be clearer and enjoyed the benefit of longer broadcast distance. The FCC also allowed 100 channels for these cordless phones. Though these cordless phones worked greatly, they were quite expensive, about $400 to $500. Frequency of 900 MHz was ideal to scrap out static and interference problems. They provided high quality sound output but were still prone to eavesdropping.

During 1994, different choices of cordless phones operating at the frequency range of 900 MHz were developed. In 1994, digital cordless phones were introduced. The digital signal transmission technology allowed the cordless phones to be more secure. This increased clarity and it also made it impossible for radio scanners to pick up this frequency for listening to other’s conversations. Thus the interference problem was almost solved.

In 1995, digital spread spectrum (DSS) technology was introduced for cordless phones. Digital Spread Spectrum served as a complete new way of sending the cordless phone signal from the base to the handset. The technology of digital spread spectrum enabled the digital information to spread in pieces over several frequencies between the receiver and the base, thereby making a complete solution for interference problem. Digital Spread Spectrum technology spreads the cordless phone signal 360 degrees so there were no dead spots and distance went up to half a mile. The digital spread spectrum technology was secure. The Cordless phones using such technology were expensive, and were available in limited choices.

Both digital cordless phones and digital spread spectrum (DSS) cordless phones were intended to increase the security of cordless phones and decrease unwanted eavesdropping by enabling the phone conversation to be digitally spread out. In 1998, the FCC granted the frequency range of 2.4 GHz for cordless phone use.

This frequency has widely increased the distance over which cordless phones can operate. Moreover, cordless phones operating at this frequency range had further increased security. Cordless phones had now reached their expected quality offering better clarity, maximum security and no noise. In 2003, the FCC granted the frequency range of 5.8 gigahertz, and till now this upward range is being used. In order to tighten security, FCC allowed manufacturers to make phones with frequencies of 2.4 GHz and 5.8 GHz.

Thus the technology in cordless phones has widely improved a lot in the past 20 years. It is really amazing that DSS cordless phone is available for less than $100 from the year 2000.