TANDY/RADIO SHACK
=================

   2500 SX/20

   Processor        80386SX                                       
   Processor Speed  20MHz                                         
   Chip Set         Unidentified                                  
   Video Chip Set   Unidentified                                  
   Maximum Onboard  5MB                                           
   Memory           
   Maximum Video    Unidentified                                  
   Memory           
   Cache            None                                          
   BIOS             Unidentified                                  
   Dimensions       254mm x 218mm                                 
   I/O Options      Floppy drive interface, IDE interface, serial 
                    port, parallel port, PS/2 mouse port, riser   
                    slot                                          
   NPU Options      80387SX                                       

<gopher://bitreich.org/I/th99/m/S-T/33816-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose            | Location  | Purpose        | Location |
   |--------------------+-----------+----------------+----------|
   | Floppy drive       |    CN1    | IDE interface  |    J1    |
   | interface          |           | LED            |          |
   |--------------------+-----------+----------------+----------|
   | IDE interface      |    CN2    | Riser slot     |   SL1    |
   |------------------------------------------------------------|
   | The location of the serial port, parallel port and PS/2    |
   | mouse port is unidentified.                                |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |               Function                | Label |  Position  |
   |---------------------------------------+-------+------------|
   |>> | Audio input source select         |  JP1  | Pins 1 & 2 |
   |   | microphone                        |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |   | Audio input source select line    |  JP1  | Pins 2 & 3 |
   |   | level                             |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |>> | Audio output source select        |  JP2  | Pins 1 & 2 |
   |   | headphone                         |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |   | Audio output source select line   |  JP2  | Pins 2 & 3 |
   |   | level                             |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |>> | Monitor type select VGA analog or |  JP3  | Pins 1 & 2 |
   |   | standard multiple frequency       |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |   | Monitor type select non standard  |  JP3  | Pins 2 & 3 |
   |   | multiple frequency                |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |>> | VGA BIOS select PS/2 mode         |  JP4  | Pins 2 & 3 |
   |   |                                   |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |   | VGA BIOS select AT mode           |  JP4  | Pins 1 & 2 |
   |   |                                   |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |>> | Video IRQ9 disabled               |  JP5  |    Open    |
   |---+-----------------------------------+-------+------------|
   |   | Video IRQ9 enabled                |  JP5  | Pins 1 & 2 |
   |   |                                   |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |>> | On board video enabled            |  JP6  | Pins 1 & 2 |
   |   |                                   |       |   closed   |
   |---+-----------------------------------+-------+------------|
   |   | On board video disabled           |  JP6  | Pins 2 & 3 |
   |   |                                   |       |   closed   |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |  Size   |  Bank 0  |         Bank 1         |    Bank 2    |
   |---------+----------+------------------------+--------------|
   |  1.5MB  |   1MB    |      (2) 256K x 9      |     None     |
   |---------+----------+------------------------+--------------|
   |   2MB   |   1MB    |      (2) 256K x 9      | (2) 256K x 9 |
   |---------+----------+------------------------+--------------|
   |   3MB   |   1MB    |       (2) 1M x 9       |     None     |
   |---------+----------+------------------------+--------------|
   |   5MB   |   1MB    |       (2) 1M x 9       |  (2) 1M x 9  |
   |------------------------------------------------------------|
   |      Note: Bank 0 is factory installed and is not          |
   |      configurable. The location is unidentified.           |
   +------------------------------------------------------------+