Because the 43 – 50 MHz cordless phone frequency was becoming increasingly crowded, the FCC granted the frequency range of 900 MHz in 1990. This higher frequency allowed cordless phones to be clearer, broadcast a longer distance (from 500 up to1000 feet), and choose from more channels (20 – 60 channels). Security, however, remained a problem with scanners and other devices still able to easily “tap into”
calls. In several countries, the use of this frequency is banned.
Digital cordless phones in the 900 MHz frequency where introduced in 1994. Digital signals allowed the phones to be more secure and decreased eavesdropping – it was pretty easy to eavesdrop on analog cordless phone conversations. In 1995 Digital Spread Spectrum (DSS) was introduced for cordless phones. This technology enabled the digital information to spread in pieces over several frequencies between the receiver and the base, Thereby making it almost impossible to eavesdrop on the cordless conversations.
