IBM Support

Telnet 3270 session hangs with keyboard locked after a logon to CICS

Troubleshooting


Problem

You are trying to logon to CICS for the first time using the selector panel from a telnet 3270 (TN3270) session. The VTAM (z/OS Communications Server) buffer trace shows a start data traffic (SDT) is done, and then nothing more. The telnet session hangs at this point with the keyboard locked. The terminal is waiting to receive a logon screen from CICS.

Symptom

Telnet 3270 session hangs with keyboard locked.

Cause

Telnet needs output from CICS to free the keyboard.

Resolving The Problem

Telnet requires output from the application to reset the keyboard internally. A workaround is to set LOGONMSG (YES) in the TYPETERM definition in CICS. This causes CICS to schedule the good morning transaction (GMTRAN) and frees the keyboard.

[{"Product":{"code":"SSGMGV","label":"CICS Transaction Server"},"Business Unit":{"code":"BU048","label":"IBM Software"},"Component":"Terminal Control","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"5.1;4.2;4.1;3.2;3.1","Edition":"","Line of Business":{"code":"LOB70","label":"Z TPS"}}]

Product Synonym

CICS/TS CICS TS CICS Transaction Server

Document Information

Modified date:
05 January 2026

UID

swg21031961

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