4020 SX  (250-4902/3)               Pinouts             Faxback Doc. # 1604

Video Port:

┌──────────┬───────────────────────────────────────┐
│Pin       │        Function                       │
├──────────┼───────────────────────────────────────┤
│1         │        Red Video                      │┌────\
│2         │        Green Video                    ││  6   \
│3         │        Blue Video                     ││    11 │
│4         │        Monitor ID Bit 2 (not used)    ││1      │
│5         │        Ground                         ││  7    │
│6         │        Red Return (ground)            ││    12 │
│7         │        Green Return (ground)          ││2      │
│8         │        Blue Return (ground)           ││  8    │
│9         │        Key (no pin)                   ││    13 │
│10        │        Sync return (ground)           ││3      │
│11        │        Monitor ID Bit 0 (Not Used)    ││       │
│12        │        Monitor ID Bit 1 (Not Used)    ││    14 │
│13        │        Horizontal Sync                ││4      │
│14        │        Vertical Sync                  ││ 10    │
│15        │        Not Used                       ││    15 │
│          │                                       ││5     /
└──────────┴───────────────────────────────────────┘└────/ 

Monochrome-type monitors use Green Video for all video input and ignore
Red Video and Blue Video.

Monitor ID Bits are not Used.  The monitor type is determined when your
system is turned on.

PS/2 CONNECTORS

Keyboard, mouse, and auxiliary device connectors

PIN ASSIGNMENTS:

  1.  Data                           6   5
  2.  Reserved                     *  ┌─┐  *
  3.  Ground                      4   │ │   3
  4.  +5 Vdc                      *   └─┘   *
  5.  Clock                        2       1
  6.  Reserved                       *   *

RS-232C SERIAL PORT

      /~~~~~~~~~~~\
    / 9   8   7   6 \
   │5   4   3   2   1│
   └─────────────────┘-

Pin assignments:

  1.  Carrier Detect
  2.  Receive Data
  3.  Transmit Data
  4.  Data Terminal Ready
  5.  Signal Ground
  6.  Data Set Ready
  7.  Request to Send
  8.  Clear to Send
  9.  Ring Indicator

PARALLEL I/O PORT

    /~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\
  /  25  24  23  22  21  20  19  18  17  16  15  14 \
 │13   12  11  10   9   8   7   6   5   4   3   2   1│
 └───────────────────────────────────────────────────┘

Pin assignment:

  1.  Strobe    
  2.  Data Bit 0 
  3.  Data Bit 1                                 
  4.  Data Bit 2                                  
  5.  Data Bit 3                                 
  6.  Data Bit 4                                 
  7.  Data Bit 5                                 
  8.  Data Bit 6                                 
  9.  Data Bit 7                                 
 10.  ACKNOWLEDGE                                
 11.  BUSY                                       
 12.  PAPER END                                   
 13.  SELECT                                     
 14.  AUTO FEED                                  
 15.  ERROR                                      
 16.  INITIALIZE                                 
 17.  SELECT IN                                  
 18-25.  Ground                                  


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