A technology developed by U.S. Robotics (now 3COM) for delivering data rates up to 56 Kbps over plain old telephone service (POTS). It was long believed that the maximum data transmission rate over copper telephone wires was 33.6 Kbps, but X2 achieves higher rates by taking advantage of the fact that most phone switching stations are connected by high-speed digital lines. X2 bypasses the normal digital-to-analog conversion and sends the digital data over the telephone wires directly to your modem where it is decoded.
3COM has announced that future X2 modems will conform to the new V.90 standard approved by the ITU. And users with older X2 modems may upgrade their modems to support V.90.
While X2 offers faster Internet access than normal modems, there are several caveats to using an X2 modem:
1. The high speeds are available only with downstream traffic (e.g., data sent to your computer). Upstream traffic is delivered using normal techniques, with a maximum speed of 40 Kbps.
2. To connect to the Internet at X2 speeds, your Internet Service Provider (ISP) must have a modem at the other end that supports V.90.
3. Even if your ISP supports V.90, you might not achieve maximum transmission rates due to noisy lines.
56K.COM - 56K modem home page Provides information and resources for the 56K owner and buyer. Offers newsflashes, a primer, upgrade and buyer's guides, modem initialization strings, drivers, and firmware updates.
U.S. Robotics home page The is the home page for US Robotics, a leading modem manufacturer. This page offers links to company information, as well as products and services for the home, office and business user.
U.S. Robotics X2 page Provides information about X2 technology, including upgrades for older modems and a list of ISPs that support X2.
