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       # TANDY/RADIO SHACK
       
          MFP/420s
       
          Processor         80486SX/80487SX                              
          Processor Speed   20MHz                                        
          Chip Set          Tandy                                        
          Max. Onboard DRAM 32MB                                         
          Cache             None                                         
          BIOS              Phoenix/Grid                                 
          Dimensions        355mm x 304mm                                
          I/O Options       Bus mouse port, floppy drive interface, IDE  
                            interface                                    
                                                                         
                            parallel port, serial port (2), VGA feature  
                            connector, VGA port                          
          NPU Options       4167                                         
       
   IMG IMG 1
          
       
          +------------------------------------------------------------+
          |                     VRAM CONFIGURATION                     |
          |------------------------------------------------------------|
          |    Size    |     VRAM      |   Location    | SW1/switch 6  |
          |------------+---------------+---------------+---------------|
          |   512KB    |   (2) 44256   |    Bank 0     |    closed     |
          |------------+---------------+---------------+---------------|
          |   1024KB   |   (2) 44256   |  Banks 0 & 1  |     open      |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                        CONNECTIONS                         |
          |------------------------------------------------------------|
          | Purpose          | Location | Purpose           | Location |
          |------------------+----------+-------------------+----------|
          | External battery |   BAT    | Floppy drive      |    C6    |
          |                  |          | interface         |          |
          |------------------+----------+-------------------+----------|
          | Board LED        |   BLED   | IDE interface     |    C7    |
          |------------------+----------+-------------------+----------|
          | VGA port         |    C1    | Power LED         |   PLED   |
          |------------------+----------+-------------------+----------|
          | Bus mouse port   |    C2    | Reset switch      |   RES    |
          |------------------+----------+-------------------+----------|
          | Parallel port    |    C3    | Speaker           |   SPK    |
          |------------------+----------+-------------------+----------|
          | Serial port 2    |    C4    | Riser card        |    S1    |
          |------------------+----------+-------------------+----------|
          | Serial port 1    |    C5    |                   |          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                 USER CONFIGURABLE SETTINGS                 |
          |------------------------------------------------------------|
          |              Function              |   Switch   | Position |
          |------------------------------------+------------+----------|
          | » | On-board Video System enabled  | SW1/switch |  closed  |
          |   |                                |     7      |          |
          |   |                                |            |   open   |
          |   |                                | SW1/switch |          |
          |   |                                |     8      |          |
          |---+--------------------------------+------------+----------|
          |   | On-board Video System disabled | SW1/switch |   open   |
          |   |                                |     7      |          |
          |   |                                |            |  closed  |
          |   |                                | SW1/switch |          |
          |   |                                |     8      |          |
          |---+--------------------------------+------------+----------|
          | » | Factory configured - do not    | SW2/switch |   open   |
          |   | alter                          |     1      |          |
          |---+--------------------------------+------------+----------|
          | » | Factory configured - do not    | SW2/switch |   open   |
          |   | alter                          |     2      |          |
          |---+--------------------------------+------------+----------|
          | » | Monitor type select color      | SW2/switch |   open   |
          |   |                                |     3      |          |
          |---+--------------------------------+------------+----------|
          |   | Monitor type select monochrome | SW2/switch |  closed  |
          |   |                                |     3      |          |
          |---+--------------------------------+------------+----------|
          | » | Factory configured - do not    | SW2/switch |   open   |
          |   | alter                          |     4      |          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |              VIDEO SWITCH CONFIGURATION (SW1)              |
          |------------------------------------------------------------|
          |      Mode      |switch 1|switch 2|switch 3|switch 4|switch |
          |                |        |        |        |        |   5   |
          |----------------+--------+--------+--------+--------+-------|
          | 56Hz vertical  |  open  |  open  |  N/A   |  N/A   |  N/A  |
          |   refresh 1    |        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          | 60Hz vertical  |  open  | closed |  N/A   |  N/A   |  N/A  |
          |   refresh 1    |        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          | 72Hz vertical  | closed |  open  |  N/A   |  N/A   |  N/A  |
          |   refresh 1    |        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          |     Enable     |  N/A   |  N/A   |  open  |  open  |  N/A  |
          |  interlaced 2  |        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          |      60Hz      |  N/A   |  N/A   |  open  | closed |  N/A  |
          |non-interlaced 2|        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          |      72Hz      |  N/A   |  N/A   | closed |  open  |  N/A  |
          |non-interlaced 2|        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          |    31.5KHz     |  N/A   |  N/A   |  N/A   |  N/A   | open  |
          |horizontal scan |        |        |        |        |       |
          |     rate 3     |        |        |        |        |       |
          |----------------+--------+--------+--------+--------+-------|
          |40KHz horizontal|  N/A   |  N/A   |  N/A   |  N/A   |closed |
          |  scan rate 3   |        |        |        |        |       |
          |------------------------------------------------------------|
          |Note 1 :When monitor resolution is 800 x 600.               |
          |                                                            |
          |Note 2 :When monitor resolution is 1024 x 768.              |
          |                                                            |
          |Note 3 :When monitor resolution is 640 x 480 or below.      |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                     DRAM CONFIGURATION                     |
          |------------------------------------------------------------|
          |       Size       |       Bank 0       |       Bank 1       |
          |------------------+--------------------+--------------------|
          |       4MB        |     (4) 1M x 9     |        NONE        |
          |------------------+--------------------+--------------------|
          |       5MB        |     (4) 1M x 9     |    (4) 256K x 9    |
          |------------------+--------------------+--------------------|
          |       8MB        |     (4) 1M x 9     |     (4) 1M x 9     |
          |------------------+--------------------+--------------------|
          |       16MB       |     (4) 4M x 9     |        NONE        |
          |------------------+--------------------+--------------------|
          |       17MB       |    (4) 256K x 9    |     (4) 4M x 9     |
          |------------------+--------------------+--------------------|
          |       20MB       |     (4) 1M x 9     |     (4) 4M x 9     |
          |------------------+--------------------+--------------------|
          |       32MB       |     (4) 4M x 9     |     (4) 4M x 9     |
          +------------------------------------------------------------+