Network Working Group                                         Jon Postel
Request for Comments: 318                                       UCLA-NMC
NIC: 9348                                                  April 3, 1972
References: RFC 139, 158, and NIC 7104


                            Telnet Protocol


   At the October 1971 Network Working Group Meeting, I promised to
   promptly produce a document which clearly and succinctly specified
   and explained the Official Telnet Protocol.  This document fails to
   meet any part of that promise.  This document was not produced
   promptly.  This document is neither clear nor succinct.  There is NO
   Official Telnet Protocol.

   The following pages present my understanding of the ad hoc Telnet
   protocol.  There are some who have serious questions about this
   protocol.  The proposed changes to the protocol are given in Section
   IV.

   Any comments should be promptly directed to me via the Network
   Information Center (Ident = JBP) or by phone (213) 825-2368 or by
   mail.

                              Jon Postel
                              SPADE Group
                              3804 Boelter Hall
                              UCLA
                              Los Angeles, California 90024






















 
RFC 318                     Telnet Protocol                   April 1972


I.  DEFINITION OF THE NETWORK VIRTUAL TERMINAL

   The Network Virtual Terminal (NVT) is a bi-directional character
   device.  The characters are represented by 8 bit codes.  The NVT has
   no timing characteristics.  The character codes 0 through 127 are the
   USASCII codes.  (Note all code values are given in decimal.)  The
   codes 128 through 255 are used for special control signals.  The NVT
   is described as having a printer and a keyboard.  The printer
   responds to incoming data and the keyboard produces outgoing data.

The Printer

   The NVT printer has an unspecified carriage width (common values are
   40, 72, 80, 120, 128, 132).  The printer can produce representations
   of all 95 USASCII graphics (codes 32 through 126).  Of the 33 USASCII
   control codes (0 through 31 and 127) the following 8 have specific
   meaning to the NVT printer.

   NAME                  CODE    MEANING

   NULL (NUL)            0       A no operation.

   BELL (BEL)            7       Produces an audible or visible signal.

   Back Space (BS)       8       Backspaces the printer one character
                                 position.

   Horizontal Tab (HT)   9       Moves the printer to next horizontal
                                 tab stop.

   Line Feed (LF)        10      Moves the printer to next line (keeping
                                 the same horizontal position).

   Vertical Tab (VT)     11      Moves the printer to the next vertical
                                 tab stop.

   Form Feed (FF)        12      Moves the printer to the top of the
                                 next page.