QUATECH, INC.
=============

   PXB-721

   Card Type          I/O controller                              
   Chipset/Controller Intel                                       
   I/O Options        8255 I/O ports (3)                          
   Maximum DRAM       N/A                                         

<gopher://bitreich.org/I/th99/i/P-R/50449-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   |        Purpose        | Location |   Purpose    | Location |
   |-----------------------+----------+--------------+----------|
   | 34-pin 8255 interface |    H1    | 34-pin 8255  |    H3    |
   | 1                     |          | interface 3  |          |
   |-----------------------+----------+--------------+----------|
   | 34-pin 8255 interface |    H2    |              |          |
   | 2                     |          |              |          |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 BASE MEMORY ADDRESS SELECT                 |
   |------------------------------------------------------------|
   | Address | SW1/1  | SW1/2  | SW1/3  | SW1/4 | SW1/5 | SW1/6 |
   |---------+--------+--------+--------+-------+-------+-------|
   |  230h   |  Off   |   On   |   On   |  On   |  Off  |  Off  |
   |---------+--------+--------+--------+-------+-------+-------|
   |  260h   |  Off   |   On   |   On   |  Off  |  Off  |  On   |
   |---------+--------+--------+--------+-------+-------+-------|
   |  2E0h   |  Off   |   On   |  Off   |  Off  |  Off  |  On   |
   |---------+--------+--------+--------+-------+-------+-------|
   |  300h   |  Off   |  Off   |   On   |  On   |  On   |  On   |
   |---------+--------+--------+--------+-------+-------+-------|
   |  350h   |  Off   |  Off   |   On   |  Off  |  On   |  Off  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  EXTERNAL INTERRUPT EDGE                   |
   |------------------------------------------------------------|
   |            Edge            |              J1               |
   |----------------------------+-------------------------------|
   |           Rising           |       Pins 1 & 3 closed       |
   |----------------------------+-------------------------------|
   |          Falling           |       Pins 1 & 2 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                      INTERRUPT SELECT                      |
   |------------------------------------------------------------|
   |   IRQ   |  J5/A  |  J5/B  |  J5/C  | J5/D  | J5/E  | J5/F  |
   |---------+--------+--------+--------+-------+-------+-------|
   |IR/FONT> |  Open  |  Open  |  Open  | Open  | Open  |Closed |
   |---------+--------+--------+--------+-------+-------+-------|
   |  IRQ3   |  Open  |  Open  |  Open  | Open  |Closed | Open  |
   |---------+--------+--------+--------+-------+-------+-------|
   |  IRQ4   |  Open  |  Open  |  Open  |Closed | Open  | Open  |
   |---------+--------+--------+--------+-------+-------+-------|
   |  IRQ5   |  Open  |  Open  | Closed | Open  | Open  | Open  |
   |---------+--------+--------+--------+-------+-------+-------|
   |  IRQ6   |  Open  | Closed |  Open  | Open  | Open  | Open  |
   |---------+--------+--------+--------+-------+-------+-------|
   |  IRQ7   | Closed |  Open  |  Open  | Open  | Open  | Open  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  PORT 1 INTERRUPT SELECT                   |
   |------------------------------------------------------------|
   |            IRQ             |              J2               |
   |----------------------------+-------------------------------|
   |             A              |   Pins 2 & 3, 4 & 5 closed    |
   |----------------------------+-------------------------------|
   |             B              |   Pins 1 & 2, 5 & 6 closed    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  PORT 2 INTERRUPT SELECT                   |
   |------------------------------------------------------------|
   |            IRQ             |              J3               |
   |----------------------------+-------------------------------|
   |             A              |   Pins 2 & 3, 4 & 5 closed    |
   |----------------------------+-------------------------------|
   |             B              |   Pins 1 & 2, 5 & 6 closed    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  PORT 3 INTERRUPT SELECT                   |
   |------------------------------------------------------------|
   |            IRQ             |              J4               |
   |----------------------------+-------------------------------|
   |             A              |   Pins 2 & 3, 4 & 5 closed    |
   |----------------------------+-------------------------------|
   |             B              |   Pins 1 & 2, 5 & 6 closed    |
   +------------------------------------------------------------+