for cordless phones. This technology enabled the spreading of the digital voice transmission over multiple frequencies, improving privacy and reducing interference between different subscribers. Frequencies United States In the United States, seven frequency bands have been allocated by the Federal Communications Commission for uses that include cordless phones. These are: 1.7 MHz (1.665–1.770 MHz, narrow-band FM) Cordless phones manufactured after October 1, 1984, are not allowed to use this band and were required to use the newer (higher) 43-50 MHz frequencies, although older telephones, on the older frequency pairs, could still be used. 27 MHz, near the Citizens Band (CB) Radio service with some frequencies being 26.010, 26.050, 26.380, 26.419 and 27.095 MHz. These were initially paired with the 1.7 MHz frequencies, then, later, with the 49 MHz frequencies. Signals were FM - frequency modulation. 43–50 MHz (Base: 43.72–46.97 MHz, Handset: 48.76–49.99 MHz, FM) Allocated in December 1983, and approved for use in mid-1984 for 10 channels. 15 additional channels allocated April 5, 1995. 900 MHz (902–928 MHz, allocated in 1993) 1.9 GHz (1920–1930 MHz, developed in 1993 and allocated in October 2005, especially with DECT 6.0) 2.4 GHz (2400–2500 MHz, allocated in 1998) 5.8 GHz (5725–5875 MHz, allocated in 2003 due to crowding on the 2.4 GHz band) Over-crowding of earlier frequency allocations led users to discontinue using telephone equipment that operated on those frequencies, leaving those bands relatively clear. Radio hobbyists monitor usage of the older equipment with telephone activity in the US AM broadcast band, some 27 MHz frequencies and most older 43-50 MHz frequencies. 1.7 MHz cordless phones were the earliest models available at retailers, and are generally identifiable by their large metal telescoping antennas. Channels just above the AM broadcast band were selected manually by the user. Some of the frequencies used are now part of the expanded AM radio band, and can be heard by anyone with an AM radio. There are reports of people still using these phones, and using them as makeshift AM radio stations that can be heard for a couple of city blocks. These models became obsolete because they are susceptible to eavesdropping, and interference from fluorescent lighting and automobile ignition systems. However, under ideal conditions they could have or more range. 43–50 MHz cordless phones had a large installed base by the early 1990s, and featured shorter flexible antennas and automatic channel selection. Due to their popularity, an overcrowding