3270 terminal function keys
Certain keys on the display station keyboard are reserved for use by IMS. If you press any of these keys (or the selector light pen or operator ID reader) when the terminal is not screen protected, IMS might not be able to recognize your action.
Recommendation: Use these keys
only when the screen is protected from receiving output.
These keys and their functions are:
- PA1 — Page advance
- The page advance key requests IMS to display the next screen of the current output message. The next screen can be the next physical page or the next logical page. The page-advance function is the only method of advancing from one physical page to the next physical page when a logical page consists of more than one physical page.
- PA2 — Message advance
- The message-advance key requests IMS to display the next message enqueued for the terminal. IMS deletes the current message, even if you have not displayed every page of it. If no more messages are waiting for the terminal, IMS leaves the current message on the screen.
- PA3 — NEXTMSGP
- The PA3 key usually performs the NEXTMSGP (message-advance protect) function, but could instead perform the Copy function.
- PF12 — Copy
- PF12 performs the Copy function for terminals that allow this function. The Copy function causes IMS to print the current display. IMS does not restore keyboard operation until it has either transferred the message to the 3270 printer (3276, 3277, or 3278) or completed the printing (3275). After a copy has completed on a 3275, reposition the cursor to an appropriate location before attempting any input.
- Clear Key
- To set the display screen to unformatted mode, press the Clear
key once. While the screen is in unformatted mode, it is protected
from receiving other output until you perform an input operation.
If IMS currently displays an output message, pressing the Clear key does not dequeue the output message.
If you press the Clear key when the terminal is not screen protected, IMS might not recognize the Clear request. However, if IMS does recognize the request, it unlocks the keyboard, displaying no data. If you press Clear and IMS responds by displaying data, the screen is invalid for input. You must press the Clear key again.
- Enter Key
- The Enter key sends to IMS either the fields currently modified by the operator or the last output message. The keyboard remains locked until IMS receives the message and restores keyboard operation.