TANDY/RADIO SHACK

4820ST/T (250-5140)

Processor       80486SX/80487SX/ODP486/ODPR486/80486DX/80486DX2
Processor Speed 20/25/33/40/50(internal)/50/66(internal)MHz
Chip Set        Unidentified
Video Chip Set  None
Maximum Onboard 64MB
Memory
Maximum Video   None
Memory
Cache           None
BIOS            Unidentified
Dimensions      330mm x 218mm
I/O Options     Floppy drive interface, IDE interface, parallel port, PS/2
                mouse port, serial ports (2)
NPU Options     80487SX

[Image]

                                CONNECTIONS

  Purpose                   Location   Purpose                   Location

  PS/2 mouse port             CN1      IDE interface               CN6

  Serial port 1               CN2      Power indicator             J1

  Serial port 2               CN3      IDE interface LED           J2

  Parallel port               CN4      External battery            J3

  Floppy drive interface      CN5      Front panel connector       J4

                        USER CONFIGURABLE SETTINGS

               Function                    Label           Position

  »   CMOS memory normal operation          JP1              Open

      CMOS memory clear                     JP1             Closed

  »   Monitor type select color            SW1/3              On

      Monitor type select monochrome       SW1/3              Off

  »   Factory configured - do not          SW1/4         Unidentified
      alter

                            DRAM CONFIGURATION

     Size         Bank 0         Bank 1         Bank 2         Bank 3

     1MB        (4) 256K x 9      None           None           None

     2MB        (4) 256K x 9   (4) 256K x 9      None           None

     3MB        (4) 256K x 9   (4) 256K x 9   (4) 256K x 9      None

     4MB        (4) 256K x 9   (4) 256K x 9   (4) 256K x 9  (4) 256K x 9

     4MB        (4) 1M x 9        None           None           None

     5MB        (4) 256K x 9   (4) 1M x 9        None           None

     6MB        (4) 256K x 9   (4) 256K x 9   (4) 1M x 9        None

     8MB        (4) 1M x 9     (4) 1M x 9        None           None

     9MB        (4) 1M x 9     (4) 1M x 9     (4) 256K x 9      None

     10MB       (4) 256K x 9   (4) 256K x 9   (4) 1M x 9     (4) 1M x 9

     12MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9        None

     16MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9     (4) 1M x 9

     16MB       (4) 4M x 9        None           None           None

     17MB       (4) 256K x 9   (4) 4M x 9        None           None

     18MB       (4) 256K x 9   (4) 256K x 9   (4) 4M x 9        None

     20MB       (4) 1M x 9     (4) 4M x 9        None           None

     24MB       (4) 1M x 9     (4) 1M x 9     (4) 4M x 9        None

     32MB       (4) 4M x 9     (4) 4M x 9        None           None

     33MB       (4) 4M x 9     (4) 4M x 9     (4) 256K x 9      None

     34MB       (4) 256K x 9   (4) 256K x 9   (4) 4M x 9     (4) 4M x 9

     36MB       (4) 4M x 9     (4) 4M x 9     (4) 1M x 9        None

     40MB       (4) 1M x 9     (4) 1M x 9     (4) 4M x 9     (4) 4M x 9

     48MB       (4) 4M x 9     (4) 4M x 9     (4) 4M x 9        None

     64MB       (4) 4M x 9     (4) 4M x 9     (4) 4M x 9     (4) 4M x 9

              CPU TYPE SELECTION

    Type      Socket       SW1/1      SW1/2

  80486SX       CPU         Off        Off

   ODP486       CPU         On          On

   ODP486       NPU         Off        Off

  ODPR486       CPU         On         Off

  80487SX       CPU         On          On

  80487SX       NPU         Off        Off

  80486DX       CPU         On         Off

  80486DX2      CPU         On         Off