USING COMET'S IBM 3278 EMULATOR (and IBM key emulation)

Comet provides an emulation of the IBM 3278 display terminal; it allows you to run programs such as FILELIST or the XEDIT full-screen editor just as if you were using an IBM 3278 terminal.  Buttons and menu items are provided which allow the user to conveniently produce the commands produced by keys on the 3278 terminal.

Moving the mouse over a point on the terminal screen will draw a heavy underline beneath that character position; pressing the mouse button will move the terminal cursor to the underlined position.  You can also select text on the screen with the mouse to Copy, Paste, Append, or Print.  (Note that Paste aborts if the text runs past the end of the current field.)

Key Assignments (see IBM menus also)

Key              3270 Action

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Return           ENTER

Shift-Return     New Line

Enter            PA2

Shift-Enter      PA1

Option-Enter     CLEAR

Shift-Tab        Back-Tab

Backspace        Backspace, Delete

The Backspace key changes its behavior when the 3270 emulator is put into "Insert" mode.  Ordinarily it produces a backspace-space-backspace, so that the text to the right of the cursor is left in its original position.  When Insert mode is ON, the Backspace key will produce a backspace-delete, so that the text to the right of the cursor shifts to the left.

You can also use the Command, Shift, and Option keys to control which action you wish the Backspace to perform.  When Command is held down while Backspace is pressed, the character to the right of the cursor is deleted, and the remaining text is shifted left.  When the Option key is held down, the result is a backspace-delete, as is the case in Insert mode.  When the Shift key is held down, the standard backspace-space-backspace will be produced.

On the left hand side, there are 12 buttons, which send the PF keys from 1 through 12.  By moving the mouse over the '?' at the top left hand you can see the labels for the buttons.

At the top of the emulator window are 11 buttons which perform actions available on 3270-type terminal keys:

Button      The Usual Effect

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Enter       Enter a line of text or a command.

PA1         Programmed Attention-1 (Toggles CP-mode).

PA2         Advance screen from "MORE..." or "HOLDING".

Clear       Advances screen from "MORE..." and clears the 

input area.

Insert      Go into Insert mode (inserts characters at

the cursor as long as there are spaces

at the end of the current field).

Reset       Cancel Insert or clear KBD-lock (KBD-lock is 

displayed on the right side of the screen).

Home        Move the cursor to the top left of the screen.

E Inp       Erase the input area.

E EOF       Erase from cursor to End of Field.

PA3         Programmed Attention-3 (application-defined).

DEL         Delete the character at the cursor position.

To the right of the buttons are two counters; the left one shows the packets sent to the network, the right one shows the packets received.  If you are using Telnet, the counter on the left may appear reversed (white on black)--this indicates that MacTCP is resending the packet to the host.

SYS-lock and KBD-lock indicators appear on the right side of the screen when one of these modes is in effect.  The host will not accept new input when the SYS-lock light is on.  When KBD-lock is on, typing produces a beep.

IMPORTANT NOTE:  You can enhance your communications efficiency when using the 3278 emulator by making sure that XEDIT has "SET FULLREAD OFF" in your PROFILE XEDIT file; XEDIT-based applications such as RICEMAIL may need to have this option turned off also to get optimal performance.  FULLREAD mode causes an extra 2,000 bytes to be sent with every PF-keystroke in the Action menu, and can significantly degrade performance on slower networks such as LocalTalk.