   |=========================================================================|
   |                                                                         |
   |           Intel External Modem Serial Port Pin Assignments              |
   |                                                                         |
   |=========================================================================|

    GENERAL INFORMATION

        Intel external modems use a DB25S (D-shell, 25-pin female) connector
        for the RS-232 serial port.  The connector on the modem's end of the
        cable must be a DB25P (D-shell, 25-pin male) connector.  The connector
        on the opposite end must mate to the serial port on your computer or
        terminal.  Consult the device's user guide for more information on its
        connector.


    ASYNCHRONOUS CABLE CONSTRUCTION

        This diagram shows you how to build a cable good for synchronous and
        asynchronous cummunications.  Most PCs, however, use RS-232
        asynchronous serial ports.  For synchronous communications, you must
        use a synchronous serial port.

        NOTE:   You must use shielded cable and shielded connector backshells
                when building the cable.

        |===========================================================|
        |Modem End | Signal                 |Signal   | DB25 | DB9  |
        |Pin Number| Name                   |Direction| Pin #| Pin #|
        |==========|========================|=========|======|======|
        |     1    |Case Ground             |   N/A   |   1  |      |
        |----------|------------------------|---------|------|------|
        |     2    |Transmitted Data (TD)   | <-----  |   2  |   3  |
        |----------|------------------------|---------|------|------|
        |     3    |Received Data    (RD)   | ----->  |   3  |   2  |
        |----------|------------------------|---------|------|------|
        |     4    |Request to Send (RTS)   | <-----  |   4  |   7  |
        |----------|------------------------|---------|------|------|
        |     5    |Clear to Send   (CTS)   | ----->  |   5  |   8  |
        |----------|------------------------|---------|------|------|
        |     6    |Data Set Ready  (DSR)   | ----->  |   6  |   6  |
        |----------|------------------------|---------|------|------|
        |     7    |Signal Ground           |   N/A   |   7  |   5  |
        |----------|------------------------|---------|------|------|
        |     8    |Carrier Detect   (CD)   | ----->  |   8  |   1  |
        |----------|------------------------|---------|------|------|
        |    15    |Transmit Data Clock     | ----->  |  15  |      |
        |----------|------------------------|---------|------|------|
        |    17    |Receive Data Clock      | ----->  |  17  |      |
        |----------|------------------------|---------|------|------|
        |    20    |Computer Ready  (DTR)   | <-----  |  20  |   4  |
        |----------|------------------------|---------|------|------|
        |    22    |Ring Indicator   (RI)   | ----->  |  22  |   9  |
        |----------|------------------------|---------|------|------|
        |    24    |External Transmit  Clock| ----->  |  24  |      |
        |===========================================================|

   ===========================================================================

   March 2, 1992             Intel FaxBACK # 4300                       Page 1
   |=========================================================================|
   |                                                                         |
   |           Intel External Modem Serial Port Pin Assignments              |
   |                                                                         |
   |============================= (continued) ===============================|

    2400EX/2400EX MNP CUSTOM CABLE DIAGRAM

        Cable specification for connecting 2400EX to _________________________.

        |============================================================|
        | Modem End |  Signal               | Signal    | Other End  |
        |Pin Number |  Name                 | Direction | Pin Number |
        |===========|=======================|===========|============|
        |     1     | Case Ground           |    N/A    |            |
        |-----------|-----------------------|-----------|------------|
        |     2     | Transmitted Data (TD) |  <-----   |            |
        |-----------|-----------------------|-----------|------------|
        |     3     | Received Data    (RD) |  ----->   |            |
        |-----------|-----------------------|-----------|------------|
        |     4     | Request to Send (RTS) |  <-----   |            |
        |-----------|-----------------------|-----------|------------|
        |     5     | Clear to Send   (CTS) |  ----->   |            |
        |-----------|-----------------------|-----------|------------|
        |     6     | Data Set Ready  (DSR) |  ----->   |            |
        |-----------|-----------------------|-----------|------------|
        |     7     | Signal Ground         |    N/A    |            |
        |-----------|-----------------------|-----------|------------|
        |     8     | Carrier Detect   (CD) |  ----->   |            |
        |-----------|-----------------------|-----------|------------|
        |    20     | Computer Ready  (DTR) |  <-----   |            |
        |-----------|-----------------------|-----------|------------|
        |    22     | Ring Indicator   (RI) |  ----->   |            |
        |============================================================|























   ===========================================================================

   March 2, 1992             Intel FaxBACK # 4300                       Page 2
   |=========================================================================|
   |                                                                         |
   |           Intel External Modem Serial Port Pin Assignments              |
   |                                                                         |
   |============================= (continued) ===============================|

    14.4EX/9600EX CUSTOM CABLE DIAGRAM

        Cable specification for connecting 14.4EX/9600EX to
        ______________________.

        NOTE:   You must use shielded cable and shielded connector backshells
                when building cables for this modem.

        |==============================================================|
        | Modem End |  Signal                 | Signal    | Other End  |
        |Pin Number |  Name                   | Direction | Pin Number |
        |===========|=========================|===========|============|
        |     1     | Case Ground             |    N/A    |            |
        |-----------|-------------------------|-----------|------------|
        |     2     | Transmitted Data (TD)   |  <-----   |            |
        |-----------|-------------------------|-----------|------------|
        |     3     | Received Data    (RD)   |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |     4     | Request to Send (RTS)   |  <-----   |            |
        |-----------|-------------------------|-----------|------------|
        |     5     | Clear to Send   (CTS)   |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |     6     | Data Set Ready  (DSR)   |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |     7     | Signal Ground           |    N/A    |            |
        |-----------|-------------------------|-----------|------------|
        |     8     | Carrier Detect   (CD)   |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |    12     | Speed Indicator         |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |    15     | Transmit Data Clock     |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |    17     | Receive Data Clock      |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |    20     | Computer Ready  (DTR)   |  <-----   |            |
        |-----------|-------------------------|-----------|------------|
        |    22     | Ring Indicator   (RI)   |  ----->   |            |
        |-----------|-------------------------|-----------|------------|
        |    24     | External Transmit  Clock|  ----->   |            |
        |==============================================================|











   ===========================================================================

   March 2, 1992             Intel FaxBACK # 4300                       Page 3
   |=========================================================================|
   |                                                                         |
   |           Intel External Modem Serial Port Pin Assignments              |
   |                                                                         |
   |============================= (continued) ===============================|

    MACINTOSH 8-PIN SCC MODEM CABLE

        Cable specification for connecting an Intel external modem to an Apple
        Macintosh.

        NOTE:   You must use shielded cable and shielded connector backshells
                when building cables for this modem.

        |============================================================|
        | Modem End |  Signal               | Signal    | Macintosh  |
        |Pin Number |  Name                 | Direction | Pin Number |
        |===========|=======================|===========|============|
        |  |- 1     | Case Ground           |    N/A    |            |
        |--|--------|-----------------------|-----------|------------|
        |  |  2     | Transmitted Data (TD) |  <-----   |    3  (TX-)|
        |--|--------|-----------------------|-----------|------------|
        |  |  3     | Received Data    (RD) |  ----->   |    5  (RX-)|
        |--|--------|-----------------------|-----------|------------|
        |  |  4     | Request to Send (RTS) |  <-----   |    1  (HSO)|
        |--|--------|-----------------------|-----------|------------|
        |  |  5     | Clear to Send   (CTS) |  ----->   |    2  (HSI)|
        |--|--------|-----------------------|-----------|------------|
        |  |  6 -|  | Data Set Ready  (DSR) |  ----->   |            |
        |--|-----|--|-----------------------|-----------|------------|
        |  |- 7  |  | Signal Ground         |    N/A    | 8 & 4 (GND)|
        |--------|--|-----------------------|-----------|------------|
        |     8  |  | Carrier Detect   (CD) |  ----->   |            |
        |--------|--|-----------------------|-----------|------------|
        |    20 -|  | Computer Ready  (DTR) |  <-----   |            |
        |-----------|-----------------------|-----------|------------|
        |    22     | Ring Indicator   (RI) |  ----->   |            |
        |============================================================|

        NOTE:   On the Intel modem end (DB25 connector), short pins 1 and 7
                together in addition to shorting pins 6 and 20.  On the
                Macintosh end (SCC 8), short pins 8 and 4 together.

        If you look at the pins of the 8-pin SCC connector, they are numbered
        like this (the block at the top represents the key which prevents you
        from incorrectly inserting the connector):

                                           *
                                         6 7 8
                                        3 4   5
                                          1 2






   ===========================================================================

   March 2, 1992             Intel FaxBACK # 4300                       Page 4