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Halting VTAM communication

The HALt command stops VTAM communication between a local and a remote CAS.

All VTAM communication between the local and remote CAS terminates immediately. After the communication link is inactive, you must use the STart command to reestablish the link to another CAS. See Starting VTAM communication for more information.


You should display the DIAGSESS view to see a list of active product and user sessions communicating with the local CAS before using the HALt command. Based on the information presented by the DIAGSESS view, you can determine the potential impact of halting communication between CASs.

After you enter the HALt command, the following conditions exist:

  • Windows opened to the remote CAS are terminated for terminal sessions logged on through the local CAS.

  • Windows opened to the local CAS are terminated for terminal sessions logged on through the remote CAS.

  • VTAM links between the local and remote CASs become inactive.

  • Windows are blank and a T appears in the window status field on the window information line.


You cannot use the HALt command against a local CAS, which is identified by a Yes in the Cur Sys field of the CASACT view.

The following forms of the HALt command are available:

  • Primary command

    The primary command is entered on the COMMAND line as follows:

    HAL system

    where system is the name of a remote CAS listed in the System field.

  • Line command

    The HAL line command is entered in the line command field ( CMD) at the left of the CASACT view. VTAM communication stops for the remote CAS where the command is entered.

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