X (input inhibited): Keyboard locked, input inhibited

What it means

The last line of a 3270 screen is the operator information area, or OIA. It belongs to the terminal, not the application. When the terminal won't accept input it shows an X there. The text or symbol that follows the X is the reason. The reasons fall into three groups, and each group clears in a different way.

Host has the keyboard. The clock symbol and X SYSTEM mean the host is working on your last request or has locked the keyboard. You wait. The application releases the keyboard when it writes back with keyboard restore set.

You did something the terminal refused. Typing in a protected field (written as X <-o-> in IBM's emulator documentation) and X -f, meaning the function isn't available, are local locks. Nothing went to the host. You press Reset and try again.

Something went wrong between host and terminal. X PROG with a number means the host sent a 3270 data stream the terminal couldn't accept. X COMM with a number means the connection failed. Reset may free the keyboard after a PROG error, but the screen may be incomplete. A COMM check stays until the connection works again.

Common causes

• You pressed Enter or another key that sends the screen, and the host hasn't answered yet (clock or SYSTEM).
• You typed with the cursor on a protected part of the screen, such as a label or an output field.
• You pressed a key the session doesn't support (X -f).
• The application sent a data stream with an error in it (X PROG 750 to 761 and others).
• The TN3270 connection is starting, failed or was dropped (X COMM 654 to 666).

How to find the problem

1. Read the whole OIA line. The symbol or word after the X names the cause, and any number after PROG or COMM narrows it down.
2. Think about the last thing you did. A key press just before the lock points to an operator lock. Sending the screen points to a host lock.
3. Look at the right side of the status line for connection state. A missing session indicator or a COMM code means the link is down.
4. If the lock is X PROG, write down the number and the transaction. A programmer will need both, plus a data stream trace if the error repeats.

How to fix it

• Press Reset for operator locks such as a protected field or X -f. Then move the cursor to an input field or use a supported key.
• Wait for clock and X SYSTEM locks. If the wait is far longer than usual, try Attn if your emulator and the application support it, or ask support to cancel the task. PA keys send the screen like Enter, so they are refused while the keyboard is locked.
• For X PROG, press Reset and then Clear, and start the transaction again. Report the number if it happens more than once.
• For X COMM, check the session's connection settings and reconnect.
• Application programmers should make sure every transaction ends with a write that restores the keyboard (FREEKB in CICS BMS, WCC bit 6 in a raw data stream).

Technical reviewer: Albert Joseph, WND Software.

Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s 3270 or 5250 display documentation.