QUATECH, INC.
PXB-721
| 
 Card Type  | 
 I/O controller  | 
| 
 Chipset/Controller  | 
 Intel  | 
| 
 I/O Options  | 
 8255 I/O ports (3)  | 
| 
 Maximum DRAM  | 
 N/A  | 
| 
 CONNECTIONS  | |||
| 
 Purpose  | 
 Location  | 
 Purpose  | 
 Location  | 
| 
 34-pin 8255 interface 1  | 
 H1  | 
 34-pin 8255 interface 3  | 
 H3  | 
| 
 34-pin 8255 interface 2  | 
 H2  | ||
| 
 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  |