   |=========================================================================|
   |                                                                         |
   |                           Modem Standards                               |
   |                                                                         |
   |=========================================================================|


    INTRODUCTION TO MODEM SPECIFICATIONS

        Intel modems support three sets of standards: Bell, MNP, and CCITT.
        Bell standards define modem operations at various speeds.  MNP defines
        several classes of error correction and data compression.  CCITT
        standards define modem operations and error correction/data
        compression, as well as diagnostic tests and RS-232 specifications for
        external modems.

        Intel modems support the standards listed below.  Any standards not
        listed are not supported.


    BELL STANDARDS as related to Intel modems

        Intel modems support these Bell specifications:

               |---|-------|-------|------|-----|------|------|------|
               |CCP|Satis- |2400B  |      |2400B|2400EX|      |      |
               |   |FAXtion|Classic|2400EX|MNP  |MNP   |9600EX|14.4EX|
        |======|===|=======|=======|======|=====|======|======|======|
        | 103  | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |------|---|-------|-------|------|-----|------|------|------|
        | 212A | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |------|---|-------|-------|------|-----|------|------|------|


    MNP STANDARDS as related to Intel modems

        Intel modems support these MNP specifications

        |-----|---|-------|-------|------|-----|------|------|------|
        |MNP  |CCP|Satis- |2400B  |      |2400B|2400EX|      |      |
        |Class|   |FAXtion|Classic|2400EX|MNP  |MNP   |9600EX|14.4EX|
        |=====|===|=======|=======|======|=====|======|======|======|
        |  1  |   |   *   |       |      |  *  |  *   |  *   |  *   |
        |-----|---|-------|-------|------|-----|------|------|------|
        |  2  |   |   *   |       |      |  *  |  *   |  *   |  *   |
        |-----|---|-------|-------|------|-----|------|------|------|
        |  3  |   |   *   |       |      |  *  |  *   |  *   |  *   |
        |-----|---|-------|-------|------|-----|------|------|------|
        |  4  |   |   *   |       |      |  *  |  *   |  *   |  *   |
        |-----|---|-------|-------|------|-----|------|------|------|
        |  5  |   |   *   |       |      |  *  |  *   |  *   |  *   |
        |-----|---|-------|-------|------|-----|------|------|------|






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   |                           Modem Standards                               |
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    CCITT STANDARDS as related to Intel modems

        Intel modems support these CCITT specifications:

                |---|-------|-------|------|-----|------|------|------|
                |CCP|Satis- |2400B  |      |2400B|2400EX|      |      |
                |   |FAXtion|Classic|2400EX|MNP  |MNP   |9600EX|14.4EX|
        |=======|===|=======|=======|======|=====|======|======|======|
        |V.21   | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.22   | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.22A  | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.22B  | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.22bis| * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.24   |   |       |       |  *   |     |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.32   |   |       |       |      |     |      |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.32bis|   |       |       |      |     |      |      |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.42   |   |       |       |      |     |      |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.42bis|   |       |       |      |     |      |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|
        |V.54   | * |   *   |   *   |  *   |  *  |  *   |  *   |  *   |
        |-------|---|-------|-------|------|-----|------|------|------|


    DEF|N|T|ONS OF STANDARDS

    BELL STANDARDS

        Bell Standards
        103 Defines 300 baud communications.  Intel modems support this
            standard.

        201C/
        201D           Defines half-duplex, 2400 baud communications using
                       Bell's proprietary protocol.  Intel modems do not
                       support these standards.

        208 Defines 4800 baud communications using Bell's proprietary protocol.
            Modems supporting this standard are mainly used on older mainframe
            computers and rarely on personal computers.  Intel modems do not
            support this standard.

        212A           Defines 1200 baud communications.  Intel modems support
                       this standard.

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    MNP STANDARDS

        Class 1        Asynchronous, byte-oriented, half-duplex data exchange.
                       About 70 percent efficient.*  Rarely used in the U.S.

        Class 2        Asynchronous, byte-oriented, full-duplex data exchange.
                       About 84 percent efficient.

        Class 3        Synchronous, bit-oriented, full-duplex data exchange.
                       About 108 percent efficient.

        Class 4        Similar to Class 3 but adds Adaptive Packet Assembly and
                       Data Phase Optimization.  About 120 percent efficient.

        Class 5        Similar to Class 4 but adds Data Compression.  About 200
                       percent efficient.**

        *   Transmission efficiency is calculated by dividing Actual bps
            Throughput by Transmission bps Rate.  ie... 1690bps / 2400bps = 70%
        **  Actual efficiency depends on the type of data transmitted.  ASC||
            text files typically compress more than COM or EXE files and thus
            transmit with greater efficiency.

        For definitions of the technical terms used here, as well as other
        pertinent information, get "Dvorak's Guide to PC Telecommunications"
        available at many book stores.


    CCITT STANDARDS

        All specifications are for the general switched telephone networks,
        unless specified otherwise.  Refer to the Supported Standards section
        for a list of the standards supported by Intel modems.

         V.21          300 bps duplex modem
         V.22          1200 bps duplex modem
         V.22bis       2400 bps duplex modem using the frequency division
                       technique
         V.23          600/1200-Baud modem
         V.24          List of definitions for interchange circuits between
                       data terminal equipment and data circuit-terminating
                       equipment
         V.25          Automatic answering equipment and/or parallel automatic
                       calling  equipment standard including procedures for
                       disabling of echo  control devices for both manually and
                       automatically established  calls
         V.25bis       Same as V.25, but using the 100-Series interchange
                       circuits V.26 2400 bps modem for use on 4-wire leased
                       telephone-type circuits
         V.26bis       2400/1200 bps modem
         V.26ter       2400 bps duplex modem using the echo cancellation
                       technique  (general switched phone networks & point-to-
                       point 2-wire leased  telephone-type circuits)

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   |                           Modem Standards                               |
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   |============================= (continued) ===============================|

         V.27          4800 bps with manual equalizer for use on leased
                       telephone-type  circuits
         V.27bis       4800/2400 bps with automatic equalizer for use on leased
                       telephone-type circuits
         V.27ter       4800/2400 bps modem
         V.28          Electrical characteristics for unbalanced double-current
                       interchange circuits
         V.29          9600 bps modem for use on point-to-point 4-wire leased
                       telephone-type circuits
         V.32          2-wire, duplex modems operating at data signalling rates
                       of up to 9600 bps for general and leased line circuits
         V.32bis       2-wire, duplex modems operating at data signalling rates
                       of up to 14400 bps for general and leased line circuits
         V.42          Error correction scheme (called LAPM) with MNP-4 fall-
                       back V.42bis Data compression techniques superior to
                       that of MNP-5
         V.54          Loop test devices/methods for modems




































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