V.90 is the official international standard for "56K" analog modems. Previously there were two competing proprietary 'defacto' standards-- K56flex (from Rockwell) and X2 (from 3COM/USR).

Buy a modem that is V.90 compliant. If you have a 56k modem that is not V.90 compliant, you may be able to upgrade it. Go to the web page for your modem manufacturer. Often, the upgrade consists of downloading some software that will change the communications protocols embedded in the (writeable) ROM of your modem.

With a reasonably good phone line and if you live within 3 1/2 miles from your central office (local phone company building), you should get connect speeds between 40K and 53K. Some lines have impairments on them, like digital pads or robbed bit signaling (RBS), which decreases the highest achievable speeds. In most cases, however, you should be able to significantly benefit from a V90 modem.

It was an unfortunate misnomer. The FCC limits legal speed on the Telephone network to 53Kbps. Actual speeds vary according to your phone line conditions. (...your actual mileage may vary)

This is to insure compatibility with various ISPs. Most ISP's support V.90. We support both V.90 and K56flex mode.

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 with older modems. 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 older 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.