is not interference from outside sources, but noise within the cordless telephone system) Frequency response not being the full frequency response available in a wired landline telephone Most manufacturers claim a range of about for their 2.4 GHz and 5.8 GHz systems, but inexpensive models often fall short of this claim. However, the higher frequency often brings advantages. The 900 MHz and 2.4 GHz band are increasingly being used for a host of other devices, including baby monitor, microwave oven, Bluetooth, and wireless LAN; thus, it is likely that a cordless phone will suffer interference from signals broadcast by those devices, and also may itself generate interference. It is also possible for a cordless phone to interfere with the 802.11a wireless standard, as the 802.11a standard can be configured to operate in the 5.8 GHz range. However, this can easily be fixed by reconfiguring the wireless LAN device to work in the 5.180 GHz to 5.320 GHz band. The newer 1.9 GHz band is reserved for use by phones that use the DECT standard, which should avoid interference issues that are increasingly being seen in the unlicensed 900 MHz, 2.4 GHz, and 5.8 GHz bands. Security Many analog phone signals are easily picked up by radio scanners, allowing anyone within range to listen in on conversations (though this is illegal in many countries). Though many such analog models are still produced, modern digital technology is available to reduce the risk of eavesdropping. Digital Spread Spectrum (DSS) typically uses frequency hopping to spread the audio signal (with a 3 kHz bandwidth) over a much wider range of frequencies in a pseudorandom way. Spreading the signal out over a wider bandwidth is a form of redundancy, and increases the signal-to-noise ratio, yielding longer range and less susceptibility to interference. Higher frequency bands provide more room for these wide-bandwidth signals. To an analog receiver like a scanner, a DSS signal sounds like bursts of noise. Only the base unit using a matching pseudorandom number can decode the signal, and it chooses from one of thousands of such unique codes each time the handset is returned to the cradle. Additionally, the digital nature of the signal increases its tolerance to noise, and some systems even encrypt the digital signal for additional security. Cordless phone handsets Roaming cordless phone handsets exist which are not tethered to any particular base station, but which also do not