  Want to run a game show?  Well you're gonna need a device that lets
  each contestant buzz in.



  Here's the specs:

    A single joystick port for the IBM PC game card has one 15-pin
    shell connector that goes to 4 buttons and two joysticks.


  The Card in the PC:                                 To the 'joystick':
  (looking at PC)                                  (sodering point of view)

     ,----.                                               ,----.
   1 | o   \              1  +5 Vdc                     1 | .   \
     |    o | 9           2  Button A1 (to 4)             |    . | 9
     | o    |             3  A's X-coord (to 1)           | .    |
     |    o |             4  Ground                       |    . |
     | o    |             5  Ground                       | .    |
     |    o |             6  A's Y-coord (to 1)           |    . |
     | o    |             7  Button A2 (to 4)             | .    |
     |    o |             8  +5 Vdc                       |    . |
     | o    |             9  +5 Vdc                       | .    |
     |    o |            10  Button B1 (to 12)            |    . |
     | o    |            11  B's X-coord (to 9)           | .    |
     |    o |            12  Ground                       |    . |
     | o    |            13  B's Y-coord (to 9)           | .    |
     |    o | 15         14  Button B2 (to 12)            |    . | 15
   8 | o   /             15  +5 Vdc                     8 | .   /
     `----'                                               `----'

   15-Pin D-Shell                                      15-Pin D-Shell
   Female Connector                                    Male Connector
   on back of PC                                       to joystick


                      Schematic Diagram for one 'Joystick'


               Button1 ----+----/\/\/\-----+
                           |    1k ohm     |
                            ||             |    Do not try to 'share' a
                           |               |    single 1k ohm by tying
               Ground  ----+               |    the buttons together,
                           |               |    otherwise all buttons will
                            ||             |    act as one.  You really
                           |               |    do need two 1k ohm resistors
               Button2 ----+----\/\/\--+   |    per joystick.
                                1k ohm |   |   
                                       |   |
               +5 Vdc  ----------------+---+-------+
                                                   |
               Y-coord -------------------+        |
                                          |        |
                                          |        |
                                          V        |
                                      -/\/\/\------+
                                      100k ohm     |
                                                   |
                                                   /
                                                   \
               X-coord --------------------------> /  100k ohm
                                                   \
                                                   |


                                      

                          Buzzer Arrangement

             A 1          A 2           B 1            B 2

              =            =             =              =
        2    | |      7   | |       10  | |        14  | |    
       -4    | |     -4   | |      - 5  | |       - 5  | |    
       +8    +-+     +8   +-+      +15  +-+       +15  +-+
              |            |             |              |
              |            |             |              |
              +----------+ +----+   +----+ +------------+
                         |      |___|      |
                         +------[___]------+

                              d-connector


  ONLY TWO WIRES ARE NEEDED TO EACH SWITCH, THE FIRST NUMBER, WHICH IS
  THE BUTTON LINE, AND THE GROUND.  THE BUTTON LINE CAN BE TIED TO THE
  VOLTAGE LINE AT THE D CONNECTOR WITH A 1K OHM RESISTOR.


  Due to the "intelligence" being in the box and not in the switches,
  we've found that you can use a 6 foot cabel from the PC to the box,
  and 25 feet of cabel between the box and the switch.  30 feet provides
  a lot of room to put cabels under carpet or play at a distance.



  Using the Device:
 
    At this point you can write your own software, OR you can use
    the BzztBzzt! software provided.


          
