Using the 3270 Terminal

The 3270 Terminal Display Emulator plug-in provides a user interface that emulates the basic functions of IBM 3270 family terminals. On the back end, the plug-in and the Zowe Application Server connect to any standard TN3270/E server.

This terminal display emulator operates as a three tier program. Due to web browsers being unable to supply TCP networking that terminals require, this terminal display emulator does not connect directly to your TN3270 server. Instead, the Zowe Application Server acts as a bridge, and uses websockets between the server and the browser for terminal communication. As a result, terminal connections only work when the stack of network programs supports websockets and the TN3270 server destination is visible to the Zowe Application Server.

The terminal connection can be customized per user and saved for future sessions using the connection toolbar of the application. The preferences are stored within the configuration dataservice storage, which can also be used to set instance-wide defaults for multiple users.

You can customize the preferences in the yaml configuration via environment variables:

• ZWED_TN3270_PORT: port number
• ZWED_TN3270_SECURITY: telnet or tls
• ZWED_TN3270_HOST: host name
• ZWED_TN3270_ROW: alternate rows
• ZWED_TN3270_COL: alternate columns
• ZWED_TN3270_MOD: screen mode, following values are supported
  • 1: 24x80
  • 2: 32x80
  • 3: 43x80
  • 4: 27x132
  • 5: Dynamic
• ZWED_TN3270_CODEPAGE: CCSID, following values are supported
  • 037, 1047, 273, 277, 278, 280, 284, 290, 297, 420, 424, 500, 838, 870, 875, 918, 924, 937, 935, 930

Example of environment variables:

zowe:
  environments:
    ZWED_TN3270_PORT: "23"
    ZWED_TN3270_SECURITY: "telnet"
    ZWED_TN3270_HOST: "lpar1.example.com"
    ZWED_TN3270_ROW: "24"
    ZWED_TN3270_COL: "80"
    ZWED_TN3270_MOD: "5"
    ZWED_TN3270_CODEPAGE: "1047"

Keyboard shortcuts

The terminal bundle that is used by tn3270-ng2 has several keyboard shortcuts to execute common TN3270 emulator functionality. The following Action and shortcut table presents the current list of what function is mapped to which key combination.

Be aware that some browsers intercept key combinations that are common to browsers, such as Ctrl+R or Ctrl+T, and that the operating system may also intercept certain combinations such as Windows+R or Alt+F4.

Also, be aware that the key combinations listed are only be handled by the terminal if the terminal has focus, which you can determine if the terminal's cursor is visible and blinking or not. To gain focus on the terminal, it is sufficient to click on the terminal's contents. The difference between focus and not focus may be the difference between F5 being interpreted as terminal PF5, or the browser reloading the page.

Action and Shortcut table

Action	Keyboard Shortcut	Note
Attention	Ctrl+a	ATTN - Attention key
Back Tab	Shift+Tab
Backspace	Backspace
Cent Sign	Ctrl+[	¢
Clear	Ctrl+Shift+z
Cursor Down	ArrowDown, NumpadArrowDown
Cursor Left	ArrowLeft, NumpadArrowLeft
Cursor Right	ArrowRight, NumpadArrowRight
Cursor Up	ArrowUp, NumpadArrowUp
Delete	Delete, NumpadDelete
Dup	Ctrl+d	DUP
End	End, NumpadEnd
Enter	Enter, NumpadEnter
Erase End of Field (EOF)	Ctrl+e	Erases from cursor position to end of field
Erase Field	Ctrl+l	Erases entire field
Erase Input	Ctrl+i	Erases contents of all input fields
Erase Word	Ctrl+w	Erases until next word, including whitespace
Home	Home, NumpadHome
Insert	Insert, NumpadInsert	Toggles insert text mode
New Line	Ctrl+Enter, Ctrl+NumpadEnter	Moves cursor to field on next row
Null	Alt+n	Deletes one character
Not Sign	Ctrl+6	¬
PA1	Alt+1
PA2	Alt+2
PA3	Alt+3
PF01	F1
PF02	F2
PF03	F3
PF04	F4
PF05	F5
PF06	F6
PF07	F7
PF08	F8
PF09	F9
PF10	F10
PF11	F11
PF12	F12
PF13	Shift+F1
PF14	Shift+F2
PF15	Shift+F3
PF16	Shift+F4
PF17	Shift+F5
PF18	Shift+F6
PF19	Shift+F7
PF20	Shift+F8
PF21	Shift+F9
PF22	Shift+F10
PF23	Shift+F11
PF24	Shift+F12
Rapid Left	Ctrl+ArrowLeft	Move cursor left by 2 positions
Rapid Right	Ctrl+ArrowRight	Move cursor right by 2 positions
Reset	Alt+r	Terminal does not lock on bad input, but rejects and auto resets. No use for reset button currently.
Vertical Bar	Ctrl+1	❘
Tab	Tab

Key sequences

Key sequences allow users to define their own key sequences. Each key sequence is a recorded set of keys with the possibility of using the key modifiers (Ctrl, Alt, Shift), function keys (F1, F2, ...) and the combinations (such as Ctrl+E or Shift+F1). The definition is stored in the _keySequences.json file.

Default key sequences

• There is a set of predefined key sequences
• Key sequences are accesible via top right menu:

Syntax of the JSON

• All key sequences can be redefined by the user
• Following syntax is required:
  • keySequences is an array of individual key sequences
  • title displayed in the key sequences menu
  • description is hover help for each item in the key sequences menu
  • keys is an array of the key strokes
    • normal for the "typewriter" keys
    • special for the function, modifiers and other special keys
      • The value corresponds to the javascript key code
    • prompt is used for user input and this input is pasted on the current cursor position
  • ctrl, alt and shift are key modifiers
  • If you combine normal, special or prompt in one array item, only one action will be made in the order of normal, special and prompt

Example

Review the following demonstration on two simple key sequences:

• Hello, world
  • Types Hello, world only
• ISPF command SWAP NEXT
  • Presses Home to get on the command line/input field
  • Ctrl+E deletes the input field
    • Ctrl+E is predefined in the TN3270 as "EOF - Erase end of field"
  • Types SWAP NEXT
  • Hits Enter

The corresponding file _keySequences.json appears as the following:

{ "keySequences":
  [
    { "title": "Hello, world",
      "description": "Types Hello, world",
       "keys": [ { "normal":  "Hello, world" } ]
    },
    { "title": "SWAP NEXT",
      "description": "ISPF: Swap next command",
       "keys": [ { "special": "Home" },
                 { "normal":  "E", "ctrl": "true" },
                 { "normal":  "SWAP NEXT" },
                 { "special": "Enter" } 
               ]
    }
  ]
}