2500 SX/20  (250-4077)              Pinouts             Faxback Doc. # 1106

Parallel I/O Printer Port:              RS-232 Serial Port:

 1     Strobe                            1    Carrier Detect
 2     Data Bit 0                        2    Receive Data
 3     Data Bit 1                        3    Transmit Data
 4     Data Bit 2                        4    Data Terminal Ready
 5     Data Bit 3                        5    Signal Ground
 6     Data Bit 4                        6    Data Set Ready
 7     Data Bit 5                        7    Request to Send
 8     Data Bit 6                        8    Clear to Send
 9     Data Bit 7                        9    Ring Indicator
10     Acknowledge
11     Busy
12     Paper End
13     Select
14     Auto Feed
15     Error
16     Initialize
17     Select-In
18-25  Ground

Keyboard and Mouse Connectors:
                                     6    5
 1     Data                          O    O
 2     Reserved                   4          3
 3     Ground                     O          O
 4     +5 Vdc                        2    1
 5     Clock                         O    O
 6     Reserved

VIDEO PORT CONNECTOR PINOUT

The following table indicates the pin functions of the video connector:

PIN           FUNCTION                                     
                                                           
 1            Red Video                                    
 2            Green Video                                  
 3            Blue Video                                   
 4            Monitor ID Bit 2 (not used)
 5            Ground  
 6            Red Return (ground)  
 7            Green Return (ground) 
 8            Blue Return (ground)  
 9            Key (no pin) 
10            Sync Return (ground) 
11            Monitor ID Bit 0 (not used) 
12            Monitor ID Bit 1 (ground) 
13            Horizontal Sync 
14            Vertical Sync 
15            Not Used 

* 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.