Telnet Data Entry Terminal option(2)

　　If the Toroidal Cursor Addressing bit is set, the sender requests or　provides that the SKIP TO LINE and SKIP TO CHAR subcommands be　supported.

　　If the Incremental Cursor Addressing bit is set, the sender requests　or provides that the UP, DOWN, LEFT, and RIGHT subcommands be　supported.

　　If the Read Cursor bit is set, the sender requests or provides the　READ CURSOR subcommand.

　　If the Line Insert/Delete bit is set, the sender requests or　provides that the LINE INSERT and LINE DELETE subcommands be　supported.

　　If the Char Insert/Delete bit is set, the sender requests or　provides that the CHAR INSERT and CHAR DELETE subcommands be　supported.

　　If the Back Tab bit is set, the sender requests or provides that the　BACK TAB subcommand be supported.

　　If the Positive Addressing bit is set, then the sender is informing　the receiver that it can only move the cursor in the positive　direction. (Note: Terminals that have this property also have a Home　function to get back to the beginning.)　facility cmd: ERASE FACILITIES subcommand code: 2

　　facility map: bit numbers

　　Erase Field 4

　　Erase Line 3

　　Erase Rest of Screen 2

　　Erase Rest of Line 1

　　Erase Rest of Field 0

　　where:

　　If a bit of the facility map for this facility command is set, the　sender requests or provides the facility indicated by the bit. For a　more complete description of each of these functions see the Erase　Functions section below.

　　facility cmd: TRANSMIT FACILITIES subcommand code: 3

　　facility map: bit numbers

　　Data Transmit 5

　　Transmit Line 4

　　Transmit Field 3

　　Transmit Rest of Screen 2

　　Transmit Rest of Line 1

　　Transmit Rest of Field 0

　　where:

　　If a bit of the facility map for this facility command is set, the　sender requests or provides the facility indicated by the bit. For a　more complete description of each of these functions see the　Transmit Functions section below.

　　facility cmd: FORMAT FACILITIES subcommand code: 4

　　facility map: bit numbers

　　FN byte 0 7

　　Modified 6

　　Light Pen 5

　　Repeat 4

　　Blinking 3

　　Reverse Video 2

　　Right Justification 1

　　Overstrike 0

　　Protection On/Off byte 1 6

　　Protection 5

　　Alphabetic-only Protection 4

　　Numeric-only Protection 3

　　Intensity 0-2

　　where:

　　If the FN bit is set, the sender requests or provides the FN　subcommand.

　　If the Modified bit is set, the sender requests or provides the　ability to indicate fields that are modified and supports the　TRANSMIT MODIFIED subcommand.

　　If the Light Pen bit is set, the sender requests or provides the　support of a light pen, including the Pen Selectable attribute of　the DATA FORMAT subcommand.

　　If the Repeat bit is set the sender requests or provides the REPEAT　subcommand.

　　If the Blinking bit is set, the sender requests or provides the　ability to highlight a string of characters by causing them to　blink.

　　If the Reverse Video bit is set, the sender requests or provides the　ability to highlight a string of characters by "reversing the video　image," i.e., if the characters are normally displayed as black　characters on a white background, this is reversed to be white　characters on a black background, or vice versa.

　　If the Right Justification bit is set, the sender requests or　provides the ability to cause entries of data to be right justified　in the field.

　　If the Overstrike bit is set, the sender requests or provides the　ability to superimpose one character over another on the screen much　like a hard copy terminal would do if the print mechanism struck the　same position on the paper with different characters.

　　If the Protection On/Off bit is set, the sender requests or provides　the ability to turn on and off field protection.

　　If the Protection bit is set, the sender requests or provides the　ability to protect certain strings of characters displayed on the screen from being altered by the user of　the terminal. Setting this bit also implies that ERASE UNPROTECTED,　DATA TRANSMIT, FIELD SEPARATOR, and TRANSMIT UNPROTECTED subcommands　(see below) are supported.

　　If the Alphabetic-only Protection bit is set, the sender requests or　provides the ability to constrain the user of the terminal such that　he may only enter alphabetic data into certain areas of the screen.

　　If the Numeric-only Protection bit is set, the sender requests or　provides the ability to constrain the user of the terminal such that　he may only enter numerical data into certain areas of the screen.