3270 Information Display System

During IMS system definition, you can specify that a 3270 system attached to IMS should operate in forced-response mode, nonresponse mode, or transaction-dependent response mode. For an Extended Terminal Option (ETO) terminal, specify these modes in the ETO user descriptor.

When 3270 terminals are not attached to IMS through VTAM® , the MTO can initiate their use by entering the appropriate /START LINE command for the lines to which the 3270 components are attached.

When 3270 terminals are attached to IMS through VTAM, they are initiated when one of the following occurs:

• The z/OS® VTAM network operator enters a VARY NET command (for example, VARY NET,ID=a,LOGON=b).
• The IMS MTO enters the /OPNDST command.
• If the 3270 terminal components are defined in the VTAM definition as belonging to IMS, VTAM makes them automatically available.
• The 3270 terminal operator enters a request to VTAM to be connected to IMS.

Each operational terminal receives a DFS059I message indicating that the terminal has been started. The MTO can use a /DISPLAY command to determine which lines are attached.