rfc1043.txt

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                provides the ability to protect certain fields displayed
                on the DET screen from being altered by the user and
                supports the ERASE-UNPROTECTED, FIELD-SEPARATOR, and
                TRANSMIT-UNPROTECTED subcommands.  (See the FORMAT-DATA
                subcommand.)

                If the Alphabetic-Only bit is set, the sender requests
                or provides the ability to constrain the user of the DET
                such that only alphabetic data may be entered into
                certain fields.  (See the FORMAT-DATA subcommand.)

                If the Numeric-Only bit is set, the sender requests or
                provides the ability to constrain the user of the DET
                such that only numeric data may be entered into certain
                fields.  (See the FORMAT-DATA subcommand.)

                The Intensity parameter is three bits wide and is
                interpreted as a positive binary integer indicating the
                number of visible levels of intensity that the sender
                requests or provides for displaying data.  (See the



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                FORMAT-DATA subcommand.)

                Reserved bits represent format facilities that are not
                defined for DODIIS implementations; therefore, no
                descriptions are provided.   Reserved bits must be
                zeroed to indicate non support of the associated format
                facilities.

   EDIT SUBCOMMANDS.  Edit subcommands are sent by the application to
   position the cursor on the DET screen.

      IAC SB DET MOVE-CURSOR <x><y> IAC SE

         subcommand code:  5

         This subcommand positions the DET cursor at screen location
         (x,y).  the <x> and <y> parameters are positive eight bit
         binary integers representing the character and line positions,
         respectively, of a DET screen location.  Values of x range
         from zero (0) through M-1, where M is the DET screen width in
         characters.  Values of y range from zero (0) through N-1,
         where N is the DET screen length in lines.

      IAC SB DET HOME-CURSOR IAC SE

         subcommand code: 12

         This subcommand positions the cursor at DET screen address
         (0,0).  It is equivalent to the MOVE-CURSOR subcommand, where
         x=0 and y=0.

   TRANSMIT SUBCOMMANDS.  Transmit subcommands are sent by the
   application to request data from the DET or by the terminal to
   identify data returned from the DET.

      IAC SB DET READ-CURSOR IAC SE

         subcommand code: 17

         This subcommand requests return of the DET cursor position.
         Use of this subcommand requires facility negotiation; see the
         EDITFACILITIES subcommand, Read-Cursor bit.

      IAC SB DET CURSOR-POSITION <x><y> IAC SE

         subcommand code: 18

         This subcommand returns cursor position in response to a



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         READCURSOR subcommand.  The <x> and <y> parameters are
         eight bit binary integers representing the cursor's position.
         The <x> and <y> parameters are positive eight bit binary
         integers representing the character and line positions,
         respectively, of a DET screen location.  Values of x range
         from zero (0) through M-1, where M is the DET screen width in
         characters.  Values of y range from zero (0) through N-1,
         where N is the DET screen length in lines.  Use of this
         subcommand requires facility negotiation; see the
         EDIT-FACILITIES subcommand, Read-Cursor bit.

      IAC SB DET TRANSMIT-SCREEN IAC SE

         subcommand code: 20

         This subcommand requests return of all characters on the DET
         screen beginning at cursor position (0,0).  M x N characters,
         where M is the DET screen width in characters and where N is
         the DET screen length in lines, are returned with a SPACE
         character returned for each character in the unwritten areas
         (the areas between defined fields).  FIELD-SEPARATOR and
         DATA-TRANSMIT subcommands are not required to delimit or
         identify fields.

      IAC SB DET TRANSMIT-UNPROTECTED IAC SE

         subcommand code: 21

         This subcommand requests return of all characters in
         unprotected fields.  Use of this subcommand requires facility
         negotiation; see the FORMAT-FACILITIES subcommand, Protection
         bit.

      IAC SB DET TRANSMIT-MODIFIED IAC SE

         subcommand code: 27

         This subcommand requests return of all characters in modified
         fields.  Modified fields are fields that have the Modified
         attribute set (see FORMAT-DATA subcommand) as well as fields
         actually modified by the user.  Use of this subcommand
         requires facility negotiation; see the FORMAT-FACILITIES
         subcommand, Modified bit.

      IAC SB DET DATA-TRANSMIT <x><y> IAC SE

         subcommand code: 28




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         This subcommand identifies a field returned in response to
         a TRANSMIT-MODIFIED subcommand.  The <x> and <y> parameters
         are positive eight bit binary integers indicating the cursor
         position of the field that follows the DATA-TRANSMIT
         subcommand.  This subcommand may precede the first field of
         a transmission with subsequent fields separated by the
         FIELD-SEPARATOR subcommand or it may precede each field.
         Use of this subcommand requires facility negotiation; see
         the TRANSMIT-FACILITIES subcommand, Data-Transmit bit.

   ERASE SUBCOMMANDS.  Erase subcommands are used by the application to
   erase the DET screen or selected DET screen areas.  In performing
   erase operations, the erased characters are replaced with SPACE
   characters.

      IAC SB DET ERASE-SCREEN IAC SE

         subcommand code: 29

         This subcommand erases all characters from the DET screen.
         All fields regardless of their attributes are deleted.  The
         cursor position after the operation is at (0,0).  If the
         protection attribute has been negotiated, the erased screen
         contains protected SPACE characters.

      IAC SB DET ERASE-UNPROTECTED IAC SE

         subcommand code: 35

         This subcommand erases all characters in the unprotected fields
         of the DET screen.  This subcommand replaces field contents
         with SPACE characters; field attributes and sizes are not
         changed.  The cursor position after the operation is at the
         beginning of the first unprotected field or, if there is no
         unprotected field, at (0,0).  Use of this subcommand requires
         facility negotiation; see the FORMAT-FACILITIES subcommand,
         Protection bit.

   FORMAT SUBCOMMANDS.  The format subcommands are used by the
   application to define the fields of a form and by the terminal to
   delimit fields sent from the DET.

      IAC SB DET FORMAT-DATA <format map><count> IAC SE

         subcommand code: 36

         This subcommand defines the attributes and size of a DET field.
         The <format map> parameter defines the field attributes and the



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         <count> parameter defines the field size.  The field starts at
         the position of the cursor when the subcommand is acted upon.
         The next <count> data characters in the data stream fill the
         field.

         The <format map> parameter is two eight bit bytes and contains
         the following:

             Byte 0
                Bit  7             Blinking
                Bit  6             Reverse Video
                Bit  5             Right Justification
                Bits 3-4           Protection
                Bits 0-2           Intensity

             Byte 1
                Bits 5-7           Reserved
                Bits 2-4           Reserved for color
                Bit  1             Modified
                Bit  0             Selectable

             where:

                If the Blinking bit is set, the following field of
                 <count> characters should have the Blinking attribute
                applied to it by the receiver.

                If the Reverse Video bit is set, the following field of
                <count> characters should be displayed by the receiver
                with video reversed.

                If the Right Justification bit is set, characters
                entered into the field by the user should be right
                justified.

                The Protection attribute is two bits wide and may take
                on the following values:

                  0  No protection.  Any valid DET data character may
                     be entered in the field.

                  1  Protected.  No data may be entered in the field.

                  2  Alphabetic-only.  Only the alphabetic characters
                     (A-Z and a-z) or the space character may be
                     entered in the field.

                  3  Numeric-only.  Only the numeric characters (0-9),



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                     the plus sign (+), the minus sign (-), the decimal
                     point (.) or the space character may be entered in
                     the field.

                The Intensity attribute is three bits wide and indicates
                the brightness to be used when displaying the characters
                in or entered into the field <count> characters wide.
                The available number of visible intensity levels should
                have been negotiated using the FORMAT-FACILITY
                subcommand. A value of zero (0) indicates that
                brightness should be OFF; that is, characters in or
                entered into the field should not be displayed.  The
                values 1-7 indicate relative brightness; the exact
                algorithm for mapping these values to the available
                levels of intensity is left to the implementors.

                If the Modified bit is set, the field is considered to
                have been modified and will be returned, along with any
                user modified fields.

                If the Selectable bit is set, the field is a candidate
                for field selection using the DET field selection
                device.

      The <count> parameter is two bytes and should be interpreted as a
      positive 16-bit binary integer that defines the field size.  The
      high order bit is transmitted first.  Data, not in the scope of
      the count of a FORMAT-DATA subcommand, should be displayed with
      the default field attributes (no blinking, no reverse video, no
      justification, no protection, not modified, not selectable, and a
      visible intensity).  Minimum field size is one (1) character.
      Maximum field size is determined by a field's starting location
      and the end of the screen or the start of the next field.

      Use of field attributes requires facility negotiation; see the
      FORMAT-FACILITIES subcommand.

   IAC SB DET REPEAT <count><char> IAC SE

         subcommand code: 37

         This subcommand permits compression of DET data by encoding
         strings of identical characters as the character and a repeat
         count.  The <count> parameter is a positive 8-bit binary
         integer.  The <char> parameter is a valid DET data character.
         Use of this subcommand requires facility negotiation; see
         the FORMAT-FACILITIES subcommand, Repeat bit.




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      IAC SB DET FIELD-SEPARATOR IAC SE

         subcommand code: 39

         This subcommand separates fields returned by the DET in
         response to TRANSMIT-MODIFIED or TRANSMIT-UNPROTECTED
         subcommands.  Use of this subcommand requires facility
         negotiation; see the FORMAT-FACILITIES subcommand,
         Protection bit.

MISCELLANEOUS SUBCOMMANDS

      IAC SB DET FUNCTION-KEY <code> IAC SE

         subcommand code: 40

         This subcommand transmits a user entered function key code.
         The <code> parameter is one byte that identifies the virtual
         function key entered.  Function key <code> values range from
         0 to 255.  This subcommand is used in conjunction with the
         ENABLE-FUNCTION-KEY subcommand.  Use of this subcommand
         requires facility negotiation; see the FORMAT-FACILITIES
         subcommand, Function-Key bit.

      IAC SB DET ERROR <cmd><error code> IAC SE

         subcommand code: 41

         This subcommand allows a DET option implementation to report
         errors it detects to the corresponding TELNET process.  The
         <cmd> parameter is one byte containing the subcommand code
         of the subcommand causing the error.  The <error code>
         parameter is one byte containing a DET error code.  (See
         Appendix 2 for DET error codes.)

         Errors should be reported when detected.  However, the
         implementation should attempt to carry out the intent of
         the subcommand or data in error.

      IAC SB DET START-OUT-OF-CONTEXT-DATA IAC SE

         subcommand code: 42

         This subcommand precedes out-of-context data.  The data
         following this subcommand and prior to the
         END-OUT-OF-CONTEXT-DATA subcommand is NOT part of the current
         form.  The out-out-of-context data should be interpreted as
         NVT mode data (i.e., it may contain carriage return and line



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RFC 1043              Data Entry Terminal - DODIIS         February 1988