Customer confusion and disappointment have blunted sales of the products, and analysts say modem makers have had a weak year.

Since then, modem makers have made enormous strides in error correction and in pushing ever more information through standard phone lines.

One of the modem makers is the Intel Corporation.

But rival modem makers produced two incompatible formats.

Hayes is a modem maker currently operating under bankruptcy-court protection.

The profitable modem makers are those that can supply their own chips or develop their own innovative software.

Each modem maker wanted to set the industry's standards.

In the late 1980's, leading high-speed modem makers all introduced their own standards for communications at 9,600 bits-per-second and faster.

For their firmware, some modem makers use "flash ROM," which can be erased and reprogrammed with new data.

U.S. Robotics, Hayes and other modem makers quickly adopted the V.32 standard for high-speed communications.