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Modem Issues
What is V.90?
Traditional modem standards assume that both ends of a modem session have an analog
connection to the public switched telephone network. Data signals are converted from
digital to analog and back again, limiting transmission speeds to 33.6Kbps (Thousand Bits
Per Second) with current V.34 modems, and due to limitations of the public telephone
network the theoretical maximum is 35Kbps. Now with V.90 technology a different assumption
is made: that one end of the modem session has a pure-digital connection to the phone
network (which Internet Service Providers and corporations already use for remote access)
and takes advantage of that high speed digital connection.
By viewing the public switched telephone network as a digital network, V.90 technology
is able to accelerate data downstream from the Internet to your computer at speeds of up
to 56Kbps *. In this way V.90 technology is different than other standards of today,
because it digitally encodes downstream data instead of modulating it as analog modems do.
The data transfer is a asymmetrical method, so upstream transmissions (mostly keystroke
and mouse commands from your computer to the central site, which require less bandwidth)
continue to flow at the conventional rates of up to 33.6Kbps. That is upstream data (Data
sent from your modem) is sent as an analog transmission that mirrors the V.34 Standard.
Only the down stream data transfer takes advantage of the high speed V.90 rates.
V.90 technology is ideal for Internet users, because you really need the 56Kbps * speed
for downloading of Web pages with sound, video and other large files. All that is needed
is for your V.90 modem to be connected to an ISP or corporate site using V.90 technology
over their digital lines to the network.
* Modems can receive data at speeds of up to 56Kbps however due to FCC (Federal
Communications Commission) rulings on maximum permissible transmit power levels during
down load transmissions, speeds of 54Kbps are the maximum. Actual data speeds received
will vary depending on line conditions.
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