AST-5250 CLUSTER                                    AST Part Number 202013-003

This board is works in AST's Premium Computers, IBM PC's, XT's, AT's or their
clones.  It is used together with 5251/11 plus or 5251/12 emulation boards to
enable four extra pcs or terminals to communicate with the system 34/36/38
through the master PC.

Installation of this board requires two IRQs open on the master pc, one high
priority IRQ for the emulation board and the other low priority IRQ for the
cluster board.


SWITCH SETTINGS

Switch setting table for IRQ selection:

            SW1-1   SW1-2  SW1-3   SW2-1   SW2-2  SW2-3
   -----------------------------------------------------
    IRQ 2     ON     OFF    OFF     OFF     OFF    OFF
    IRQ 3    OFF      ON    OFF     OFF     OFF    OFF
    IRQ 4    OFF     OFF     ON     OFF     OFF    OFF
    IRQ 5    OFF     OFF    OFF      ON     OFF    OFF
    IRQ 6    OFF     OFF    OFF     OFF      ON    OFF
    IRQ 7    OFF     OFF    OFF     OFF     OFF     ON
   -----------------------------------------------------

Switch bank SW3 setting:

    SW3-1  OFF  (Always OFF for 5250 Cluster)
    SW3-2  ON   Selects 02BFh range ( PC or AT or their clones )
           OFF  Selects 01BFh range ( XT or XT Clones)
    SW3-3  ON   Interrupt sharing disable ( Leave it always ON)
    SW3-4  OFF  Reserved (Leave it always OFF)


SWITCH LOCATIONS

    ͻ
                                                     
                                                    Ķ
                                                     
                                                     
                                                     
                                                     
        SW1     SW2     SW3                          
      +-----+ +-----+ +-----+ ON                     
      | 1-3 | | 1-3 | | 1-4 |                        
      +-----+ +-----+ +-----+ OFF                   Ķ
    ͻ            ͼ 
                                   ͼ      
                                                       
