C.1 The ASCII Character Set (VMS, U*X)

Figure C-1 represents the ASCII character set (characters with decimal values 0 through 127). The first half of each of the numbered columns identifies the character as you would enter it on a terminal or as you would see it on a printer. Except for SP and HT, the characters with names are nonprintable. In Figure C-1, the characters with names are defined as follows:

NUL  Null  DC1  Device Control 1 (XON) 
SOH  Start of Heading  DC2  Device Control 2 
STX  Start of Text  DC3  Device Control 3 (XOFF) 
ETX  End of Text  DC4  Device Control 4 
EOT  End of Transmission  NAK  Negative Acknowledge 
ENQ  Enquiry  SYN  Synchronous Idle 
ACK  Acknowledge  ETB  End of Transmission Block 
BEL  Bell  CAN  Cancel 
BS  Backspace  EM  End of Medium 
HT  Horizontal Tab  SUB  Substitute 
LF  Line Feed  ESC  Escape 
VT  Vertical Tab  FS  File Separator 
FF  Form Feed  GS  Group Separator 
CR  Carriage Return  RS  Record Separator 
SO  Shift Out  US  Unit Separator 
SI  Shift In  SP  Space 
DLE  Data Link Escape  DEL  Delete 

The remaining half of each column identifies the character by the binary value of the byte; the value is stated in three radixes- octal, decimal, and hexadecimal. For example, the uppercase letter A has, under ASCII conventions, a storage value of hexadecimal 41 (a bit configuration of 01000001), equivalent to 101 in octal notation and 65 in decimal notation.

Figure C-1 Graphic Representation of the ASCII Character Set

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