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   |                      What is Data Compression?                          |
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        This document briefly describes the effects of compression on modem
        data transmissions.


    WHAT IS DATA COMPRESSION?

        Data compression allows modems to increase through-put without
        increasing the baud rate (transmission speed).  With data compression,
        the sending modem compresses the data into a compact form.  The
        receiving modem decompresses the data back to its original form.  You
        save time and money because your information is transmitted much more
        quickly.

        V.42bis is a data compression standard for 9600 bps modems.  It
        compresses data by as much as 4:1, depending on the type of file you
        send.  Thus, a 9600 baud modem can transmit your data at up to
        38,400bps (bits per second) using V.42bis.

        Another method of data compression is a de facto standard known as
        Microcom Networking Protocol (MNP) Level 5.  MNP 5 provides up to 2:1
        data compression.  This gives a 2400 baud modem and effective
        throughput of as much as 4800 bps, and a 9600 baud as much as 19,200
        bps.

        Data compression can occur only when the two communicating modems
        support the same compression techniques.  If modems supports more than
        one type of compression, the communicating modems will use the most
        powerful technique common to both.
























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   November 8, 1991          Intel FaxBACK # 4304                       Page 1