The Host Connection Program's e789 and xhcon commands provide special characteristics for using the 3270 keyboard.
The 3270 keyboard is locked under conditions indicated in the Operator Information Area (OIA):
The Presentation Space (PS) emulator screen contains fields and field attributes. When an attribute is reached while typing data into a field, the cursor automatically moves to the next unprotected field location instead of locking the keyboard and leaving the cursor on the attribute. Cursor movement keys unlock the keyboard in addition to performing their standard functions. Usually, a keyboard locks because of an attempt to enter data in an incorrect place.
Use the following cursor movement keys to unlock the keyboard:
| Key Name | Function |
|---|---|
| LEFT | |
| Cursor left | |
| RIGHT | |
| Cursor right | |
| DOWN | |
| Cursor down | |
| UP | |
| Cursor up | |
| HOME | |
| Cursor home | |
| ENDF | |
| End field | |
| LENDF | |
| Left end field | |
| TAB | |
| Forward tab | |
| BTAB | |
| Backward tab | |
| NEWLINE | |
| New line | |
| ERASE | |
| Erase input | |
| RESET | |
| Reset | |
| BACKSPACE | |
| Backspace | |
| FTABW | |
| Forward word tab | |
| BTABW | |
| Backward word tab | |
If, as the result of trying to insert characters into a full field, the keyboard locks and X 0 > (uppercase X, zero, greater-than symbol) displays in the OIA, the INSERT, DELETE, or DELWORD key unlocks the keyboard. If the keyboard locks and X -f (uppercase X, minus f) displays in the OIA, any Attention key unlocks the keyboard (as well as performing its standard function).
The special keys include functions that appear on the 3278/79 keyboards, such as PF1 and ENTER, and special emulator keys, such as DELWORD and FTABW, that move the cursor, add and delete text, and switch active emulator screens.
Each special emulator key has a default key sequence. By using the keyboard definition utility, different key sequences can be assigned to a specific key function.
| Attention Keys | Includes the CLEAR, ENTER, PF1 to PF24, PA1 to PA3, CURSEL (cursor select), SYSREQ, and ATTN keys.
Note: The SYSREQ and ATTN keys are only used for SNA connections. The ATTN key is always supported by TCP/IP. |
| BACKSPACE and BACKF Keys | Deletes the character under the cursor and moves the remaining characters in the field to the left. If a field contains several lines, characters move from one line to another.
The functional difference between the BACKSPACE and BACKF keys is the processing performed when an attribute byte is deleted. The BACKSPACE key moves the cursor to the left when the cursor is on a protected screen location. It does not lock the keyboard or jump fields. In an SBCS field, when the BACKF key detects an attribute byte while backspacing, it moves the cursor to the last nonnull, nonspace character of the previous unprotected field and erases it. In a DBCS field, when the BACKF key detects an attribute byte while backspacing, it moves the cursor to the last nonnull, nonspace, nonshift-in (SI) character of the previous unprotected field and erases it. |
| CHGDIS | Switches to an auxiliary display if one is operating. If the auxiliary display is not started or if the secondary display card has no display attached to it, the CHGDIS key appears to lock up the current physical display. This happens because the emulator is trying to use the secondary display and is not aware of its unavailability. The xhcon command does not support this function. |
| CLICK | Toggles keyboard clicking on or off. The xhcon command does not support this function. |
| Cursor Movement Keys | Moves the cursor. The keys and resulting cursor movements include: |
| DELETE | Deletes the character located at the cursor. The cursor does not move. All remaining characters to the right of the cursor in the same field shift one or two columns to the left, depending on whether a single-byte or double-byte character is deleted. This key also unlocks the keyboard if X 0 > (uppercase X, zero, greater than symbol) displays in the OIA as a result of attempts to insert too much data into a field. |
| DELWORD | Deletes characters from the cursor to the end of the word; the words following are shifted to the left. This deletion includes punctuation and one space or null character following the word. For a partial word deletion, the trailing space or null character is not deleted. The cursor is left at its current location. For word deletion, a word or field does not wrap the screen. If the cursor is positioned at a null character or space, the null or space is deleted. If the cursor is on an attribute or protected field, input is inhibited and X < 0 > (uppercase X, less than symbol, zero, greater than symbol) is displayed in the OIA. This key is not supported in the DBCS environment. |
| DOIA | Toggles between the OIA and row 24 on ASCII terminals with a screen size of 24 lines. This key performs no function when the e789 command is executed on screen displays with more than 24 rows. The xhcon command does not support this function. |
| DUP | Informs the application program a duplicate operation is indicated for the rest of the field where it is located. When entered in an SBCS field, the DUP key displays as a blank and tabs forward to the next field. The DUP key is displayed as an * (asterisk) when entered in a DBCS field . If the cursor is on an attribute or protected field, input is inhibited and X < 0 > (uppercase X, less than symbol, zero, greater than symbol) is displayed in the OIA. |
| ENDF | In an SBCS field, moves the cursor to one position past the last nonnull, nonspace character in the field. In a DBCS field, ENDF moves the cursor to one position past the last nonnull, nonspace, nonSI character in the field. If a field is full, the cursor is moved to the attribute byte of the next field. |
| EOF | Clears the character location occupied by the cursor as well as all remaining character locations in that field, if the cursor is located in an unprotected field. If the cursor is in a DBCS field, the location from the cursor to the end of the field is set to DBCS nulls. |
| ERASE | Clears all unprotected character locations, sets all character attributes to their default values, and repositions the cursor to the first unprotected character location on the display. |
| FMARK | Informs the application program of the end of a field in an unformatted buffer or subfield of a formatted buffer. When entered in an SBCS field, the FMARK key displays as a blank. The FMARK key displays as a ; (semicolon) when entered in a DBCS field . If the cursor is positioned at a field-attribute location or is within a protected field, input is inhibited and X < 0 > (uppercase X, less than symbol, zero, greater than symbol) is displayed in the OIA. |
| FTABW and BTABW Keys | Allows the cursor to move to the next or previous word with a single keystroke. A word is one or more nonnull, nonspace characters. Words are separated by nulls or spaces. This kind of tabbing places the cursor on the first character of the next or previous word or at the upper leftmost position of the display, if no text exists.
This tabbing ignores field attributes and only looks at the characters displayed on the screen. Thus, it is possible to tab through protected field locations. Normal 3270 field-tab keys are provided for moving the cursor to the next and previous unprotected fields. These word-tab keys are not supported for DBCS. Note: The following special emulator keys, related to four-byte operations, are not supported in the DBCS environment: |
| HCONUTIL | Invokes the HCON utility program. While the HCON utility is executing, the host can modify the internal presentation space of the emulation session. When the utility ends, the emulation session regains use of the virtual terminal. With the xhcon command, the hconutil is run in a separate AIXwindow and the display session continues to be active. |
| HOME | Positions the cursor at the first unprotected character location on the display. |
| INSERT | Operates as it does on a 3278/79, with additional features. The INSERT key puts the terminal into insert mode. This is indicated by a ^ (caret) in the OIA. All subsequent keyed characters are inserted rather than overwritten. If the field becomes full while in insert mode and there are trailing blanks at the end of the field, those blanks are shifted out of the field. Characters can then be entered until there are no nulls or trailing blanks left in the field.
Insert mode may be terminated by pressing the RESET key. The INSERT key also acts as a toggle, so that pressing this key while in insert mode resets the terminal to replacement mode. |
| JOBCTRL | Allows suspension of the emulator if run from a shell that supports job control. While the e789 process is suspended, the keyboard and display are released to the parent shell. The host may modify the internal presentation space of the emulation session. The xhcon command does not support this function.
The e789 process cannot be put into the background. Attempting to do this results in the e789 process remaining suspended and displays a message. To put the e789 process back into the foreground, enter: fg <job #> |
| LENDF | Moves the cursor to the first nonnull, nonspace character in a SBCS field. In a DBCS field, LENDF moves the cursor to the first nonnull, nonspace, non-shift-out character in a field. If a field is empty, the cursor is moved to the first position of the current field. |
| NEWLINE | Moves the cursor to the next line and wraps to the top of the screen for the last line. |
| NEXT | Makes the next session the active session. For example, if four sessions are started by entering e789 abcd , four sessions with session names of a , b , c , and d are established. Session a is the active session and is usable on the display. Pressing the NEXT key causes session b to become active. Pressing the NEXT key three more times activates the c , d , and a sessions in succession. This key performs no function if only one session is available. |
| POREST | Emulates power-on reset. This is equivalent to turning on the power for a 3278/79 display. The ENTER key may need to be pressed before the logo is displayed again, as on the 3278/79 display, if the session is a DFT or display session. |
| Prints the contents of the display on the printer associated with the local system. This key does not provide the same function as the Local Copy key found on the 3278/79 display. | |
| QUIT | Terminates the emulator session, which is the same as turning off a 3278/79 display. |
| REFRESH | Refreshes the current screen on the active display session. |
| REPLS | Replaces the contents of the replace file specified in the session profile with the contents of the display. |
| RESET | Unlocks the keyboard after an attempt to type data in the incorrect place on the screen (for example, in a protected screen location) or an attempt to insert too much data into a field. The RESET key also terminates insert mode. In addition to the RESET key, any of the cursor movement keys may be used to reset the keyboard. |
| SAVES | Appends the contents of the display to the save file specified in the session profile. |
| SHELL | Invokes a subshell specified by the SHELL environment variable. While the subshell is executing, the host may modify the internal presentation space of the emulation session. When the subshell is terminated, the emulation session regains use of the virtual terminal. The xhcon command does not support this function. |
| SHIFTDISP | Toggles SO/SI display mode in a DBCS environment. When toggled on, SO is displayed as a < (less than symbol) and SI is displayed as a > (greater than symbol). This key is only supported in a DBCS environment. |
| SPACEOF | Performs the same functions as the 3270 EOF key except the space character, rather than the null character, performs the erasure. If the cursor is in a DBCS field, the locations from the cursor to the end of the field are set to DBCS space. |
| TAB and BTAB | Moves the cursor to the next and previous unprotected fields. These are the normal 3270 field-tab keys. |
| XLATE | Allows DBCS users to switch displayed character sets locally. For Japan, this switches between Japanese-English and katakana characters. This key is only supported in a Japanese Language environment. |
The unsupported 3270 print control keys include: