3COM CORPORATION
================

   VARMODEM 1200

   Modem Type               Data (synchronous/asynchronous)       
   Maximum Data Rate        1200bps                               
   Data Bus                 8-bit ISA                             
   Data Modulation Protocol Bell 103A/212A                        
                                                                  
                            ITU-T V.21, V.22                      

<gopher://bitreich.org/I/th99/t/0-9/54133-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   |      Purpose      | Location |     Purpose      | Location |
   |-------------------+----------+------------------+----------|
   | Line out          |   CN1    | Volume           |    R1    |
   |-------------------+----------+------------------+----------|
   | Line in           |   CN2    |                  |          |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  MULTI-LINE INSTALLATION                   |
   |------------------------------------------------------------|
   | Setting                       |             J1             |
   |-------------------------------+----------------------------|
   |>> Single modem                |            Off             |
   |-------------------------------+----------------------------|
   | Multi-line                    |             On             |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                    TRANSMISSION FORMAT                     |
   |------------------------------------------------------------|
   | Setting                       |             J2             |
   |-------------------------------+----------------------------|
   |>> 10-bit                      |            Off             |
   |-------------------------------+----------------------------|
   | 11-bit                        |             On             |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                           RESET                            |
   |------------------------------------------------------------|
   | Setting                       |            J14             |
   |-------------------------------+----------------------------|
   |>> Enabled                     |            Off             |
   |-------------------------------+----------------------------|
   | Disabled                      |            N/A             |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                FACTORY CONFIGURED SETTINGS                 |
   |------------------------------------------------------------|
   |            Jumper            |           Setting           |
   |------------------------------+-----------------------------|
   |              J3              |             On              |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 BASE I/O ADDRESS SELECTION                 |
   |------------------------------------------------------------|
   |        Port        |        J10         |       J11        |
   |--------------------+--------------------+------------------|
   |    COM1: (3F8h)    | Pins 2 & 3 closed  |       Off        |
   |--------------------+--------------------+------------------|
   |    COM2: (2F8h)    | Pins 2 & 3 closed  |        On        |
   |--------------------+--------------------+------------------|
   |    COM3: (3E8h)    | Pins 1 & 2 closed  |       Off        |
   |--------------------+--------------------+------------------|
   |    COM4: (2E8h)    | Pins 1 & 2 closed  |        ON        |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                    INTERRUPT SELECTION                     |
   |------------------------------------------------------------|
   |            IRQ             |              J12              |
   |----------------------------+-------------------------------|
   |             3              |       Pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |             4              |       Pins 1 & 2 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                        AUTO ANSWER                         |
   |------------------------------------------------------------|
   | Setting              |                SW1/1                |
   |----------------------+-------------------------------------|
   |>> Off                |     Modem answers on first ring     |
   |----------------------+-------------------------------------|
   | On                   | Modem does not answer on first ring |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                       CARRIER DETECT                       |
   |------------------------------------------------------------|
   | Setting                    |             SW1/2             |
   |----------------------------+-------------------------------|
   |>> Off                      |           CD normal           |
   |----------------------------+-------------------------------|
   | On                         |        CD forced high         |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                          PBX MODE                          |
   |------------------------------------------------------------|
   | Setting                 |              SW1/3               |
   |-------------------------+----------------------------------|
   |>> Off                   | Normal dial up line equalization |
   |-------------------------+----------------------------------|
   | On                      |          PBX operation           |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                         DTR SIGNAL                         |
   |------------------------------------------------------------|
   | Setting                    |             SW1/4             |
   |----------------------------+-------------------------------|
   |>> Off                      |          DTR normal           |
   |----------------------------+-------------------------------|
   | On                         |        DTR forced high        |
   +------------------------------------------------------------+