K56flex
K56flex (also K56 + ) is a data transmission method for analog modems developed by Rockwell .
K56flex is an asymmetrical transmission method in which only the downstream (download) achieves the maximum possible data transmission rate of 56,000 bit / s. The upstream is limited to 33,600 bit / s. The transmission method can only be used in digital telephone networks in which the user of the modem has an analog connection and the remote terminal has a digital connection. After the official ITU-T standard V.90 was adopted in September 1998, the K56flex process is of little interest.