Annotated edit history of
MoDem version 5, including all changes.
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LawrenceDoliveiro |
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An abbreviation of __Mo__dulator/__Dem__odulator, a device used to transmit/receive digital data via an analog communication channel. Common kinds of modems: |
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* acoustic modem -- the original kind of modem, where the analog channel is a telephone voice line. These days most commonly used for dial-up Internet access, once upon a time also heavily used for connecting to [BBS]es. |
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* ADSL modem -- connects to [ADSL] service, which takes advantage of the fact that the copper wires used for telephone landline service have a much greater bandwidth than is needed for just voice. |
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* cable modem -- connects to an Internet service provided by a cable TV company. |
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PhilHarper |
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LawrenceDoliveiro |
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''Modulation'' refers to any kind of technique whereby a ''carrier'' signal output by the transmitting end has its characteristics altered in some systematic way that can be detected by the receiving end, in order to convey information. |
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AristotlePagaltzis |
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LawrenceDoliveiro |
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Most kinds of modems nowadays are not symmetrical--they are designed to communicate with special equipment belonging to a central service provider, not with a modem bought by another ordinary person-off-the-street. Acoustic modems still have symmetrical communication capability, but only at speeds up to 33.6kb/s (V.34). The higher 56kb/s speed (V.90) only works with special equipment at the provider end. |
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PeterHewett |
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LawrenceDoliveiro |
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Most modern acoustic MoDem~s, so-called WinModem~s, do not contain the hardware necessary to perform all of this operation. Instead, they rely on the host [CPU] for much of the signal processing. Because the software to do this is part of the MoDem driver, and many vendors write drivers only for MicrosoftWindows, some WinModem~s cannot be operated under [Linux]. |