Sep 24, 2003 11:51 AM
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(Updated Sep 24, 2003 11:51 AM)
Basic info on the terms Analog & Digital:
Analog:
Analog data is a series of waves. Eg: a vinyl record, which represents audio in sound waves, takes ur voice & turns it into a wave. The sound quality can vary with analog, but in theory it has less fidelity than does digital.
Digital:
Digital data converts analog waves into a stream of binary numbers (1's & 0's) & records the numbers instead of the wave. Eg: The information in a CD is the same every time, so there is no quality loss. That's why CDs mostly sound better than vinyl.
Analog Vs. Digital Cellphones
Analog Cellphones:
Analog phones take the audio from ur voice & represent it like electromagnetic waves. The sound waves are transferred in a continuous form of data. When analog cell phones were 1st developed, no 1 knew how popular mobile communications would become. Each analog cell antenna can carry only 56 simultaneous phone conversations. In dense urban areas, this isn't nearly enough. Analog service is fairly ubiquitous.
Digital Cellphones:
Digital phones take ur analog sound waves & sample it at various rates. These rates are usually lower so as to save space rather than to preserve audio fidelity. A digital cellphone system compresses ur call's signal, which means a digital cell antenna can carry many more than 56 conversations at once.
Digital cell service isn't available everywhere. At present, many places still have only analog cell service.
Dual-Band Mode Cellphones:
U need a dual-mode cell phone to connect to both Analog & Digital services. If u travel in the United States, make sure ur new digital cell phone supports analog (AMPS) systems.
U might also see ''dual band'' on a digital phone's spec sheet. This means it works with both 800-MHz & 1900-MHz digital cell systems in America. Europe's GSM network uses 900-MHz & 1800-MHz digital cell systems in most phones. In India, Orange, Hutchison Telecom & AirTel provide Dual-Band Networks (8-MHz in 900-MHz band & 2-MHz in 1800-MHz band)
Cellphone Privacy
If u're worried about the privacy of ur cell phone conversations, be especially concerned if u are on an analog phone. Eavesdropping is much easier with analog sound waves. Because of the similarity to FM radio transmission, eavesdropping can be as easy as tuning into the proper frequency. Cellphone towers transmit a 824- to 849-MHz spectrum, which is just slightly above the police band. Because analog waves are not encrypted, u can adjust a police scanner to tune into cellphone conversations.
Digital cellphones are harder to eavesdrop on. A digital stream is more difficult to interpret because it's not a radio wave, but rather a series of 1's & 0's. The hardware necessary to convert digital streams is not as readily available as are FM scanners.
Don't be fooled, though. Digital cellphones may offer slightly more privacy, but they can still be scanned, converted into an analog wave, smoothed out, & listened to.
Incase u need privacy, the best advice is to limit ur cellphone conversations to discussions u don't care about others hearing. Incase the privacy part doesn't mean much to u, u should have nothing to fear by ur conversations being overheard. Just be aware that they're out there & they're listening.
