Telnet Data Entry Terminal option(5)

　　All fields regardless of their attributes are deleted. The cursor　position after the operation will be (0,0). Most terminals set the erased characters to either NUL or space characters.

　　IAC SB DET ERASE LINE IAC SE subcommand code: 30

　　This subcommand causes all characters on the yth line to be removed　from the screen, where y is the line of the current cursor position.

　　All fields regardless of their attributes are deleted. The cursor　position after this operation will be (0,y). Note: This operation　can be easily simulated by the sequence: LINE DELETE, LINE INSERT.

　　However, the order is important to insure that no data is lost off　the bottom of the screen.

　　IAC SB DET ERASE FIELD IAC SE subcommand code: 31

　　This subcommand causes all characters in the field occupied by the　cursor to be removed. The cursor position after the operation is at　the beginning of the field.

　　IAC SB DET ERASE REST OF SCREEN IAC SE subcommand code: 32

　　This subcommand causes all characters from position (x,y) to　(M-1,N-1) to be removed from the screen. All fields regardless of　their attributes are deleted. The cursor position after the　operation is unchanged. This is equivalent to doing an ERASE REST OF　LINE plus a LINE DELETE for lines greater than y.

　　IAC SB DET ERASE REST OF LINE IAC SE subcommand code: 33

　　This subcommand causes all characters from position (x,y) to (M-1,y)　to be removed from the screen All fields regardless of their　attributes are deleted. The cursor position after the operation is　unchanged.

　　IAC SB DET ERASE REST OF FIELD IAC SE subcommand code: 34

　　This subcommand causes all characters from position (x,y) to the end　of the current field to be removed from the screen. The cursor　position after the operation is unchanged.

　　IAC SB DET ERASE UNPROTECTED IAC SE subcommand code: 35

　　This subcommand causes all characters on the screen in unprotected　fields to be removed from the screen. The cursor position after the　operation is at (0,0) or, if that position is protected, at the　beginning of the first unprotected field.

　　Format Functions

　　IAC SB DET FORMAT DATA IAC SE　subcommand code: 36

　　where is a two byte field containing the following

　　flags:

　　Byte 0

　　Blinking 7

　　Reverse Video 6

　　Right Justification 5

　　Protection 3-4

　　Intensity 0-2

　　Byte 1

　　Modified 1

　　Pen Selectable 0

　　where:

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

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

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

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

　　0 no protection

　　1 protected

　　2 alphabetic only

　　3 numeric only

　　The protection attribute specifies that the other side may modify　any character (no protection), modify no characters (protected),　enter only alphabetical characters (A-Z, and a-z) (alphabetic only),　or enter only numerical characters (0-9,+,.,and -) (numeric only) in　the following field of bytes.

　　The Intensity field is 3 bits wide and should be interpreted in the　following way:

　　The values 0-6 should be used as an indication of the relative　brightness to be used when displaying the characters in or entered　into the following field characters wide. The number of　levels of brightness available should have been obtained　previously by the Format Facility subcommand. The exact algorithm　for mapping these values to the available levels of intensity is　left to the implementors. A value of 7 in the intensity field　indicates that the brightness should be off, and any characters in　or entered into the field should not be displayed.

　　If the Modified bit is set, the field is considered to have been　modified and will be transmitted in response to a TRANSMIT MODIFIED　subcommand.

　　If the Pen Selectable bit is set, the field can be selected with the　light pen. Note: Use of the light pen should be the subject of　another Telnet option.

　　is 2 bytes that should be interpreted as a positive 16-bit　binary integer representing the number of characters following this　command which are affected by it.