Superfast But Picky
A new breed of modem is promising personal-computer users the ability to send data over phone lines at up to 28,800 bits, or roughly 500 words, per second. That's twice as fast as the speediest units now generally used. But unless you have specialized needs, you might want to hold off buying. Tests in the labs of NSTL/McGraw-Hill revealed that the top-rated Hayes Optima 28800 V.FC ($579) and similar modems live up to their promise only when communicating with another modem of the same type. Even if different 28,800-bit brands are Hayes-compatible, they often have to drop down to a slower speed to talk to each other. A recently approved international standard will solve the problem, but it won't be incorporated into all of the superfast new modems for a while.