Warning: Speed Bumps for 56K

Faster, web cruiser, faster! That’s the promise of the new, much-ballyhooed 56 Kbps modems. But will a 56 Kbps modem really give your home-office Web connection a twofold boost in speed? I don’t think so.

First speed bump:

U.S. Robotics and Rockwell are producing 56 Kbps modems that are based on incompatible standards. If you call up one modem with the other, they’ll refuse to talk to each other at 56 Kbps. Instead they’ll slow down to 33.6 Kbps. U.S. Robotics is taking the lead with its x2 technology, which it’s introducing in models such as the Courier V.Everything 56K modem. As of this writing, however, Motorola’s ModemSURFR 56K and VoiceSURFR 56K modems, which are based on Rockwell’s K56Flex chips, are due to hit the stores — and the squabble over standards remains unsettled.

Second speed bump:

Even when a compromise over compatibility is reached, a 56 Kbps modem still won’t deliver 56 Kbps Net cruising. That’s because most telephone lines aren’t up to the challenge. According to my tests, the new modems don’t run any faster than 48 Kbps, and that’s just when you’re downloading files to your computer. If you email a large file, the fastest speed you’ll attain is around 28.8 Kbps.

Bottom line:

Stick with a 28.8 Kbps modem and wait until the competing 56 Kbps camps agree on a single standard. In the meantime, prices for the new modems will fall.

Coordinates: Courier V.Everything 56K, $395. U.S. Robotics, 800-877-2677,; ModemSURFR 56K and VoiceSURFR 56K, from $159 to $199. 800-426-6336,