You can activate VTAM® traces when VTAM is started or as needed. Use the TRACE option on the START command to begin the trace when VTAM is started, or use the MODIFY TRACE command to begin the trace when VTAM is already running. The trace start option and the MODIFY TRACE command have additional parameters unique to the type of trace being started. For more information about using the trace start option and the MODIFY TRACE command, see z/OS Communications Server: SNA Operation.

Before you start the VTAM buffer contents trace, start GTF with the USR option; otherwise, none of the trace data is recorded. For information about starting GTF, see z/OS MVS Diagnosis: Tools and Service Aids.

For more information about the VTAM buffer contents trace, the TRACE start option, and MODIFY TRACE command, see z/OS Communications Server: SNA Operation.

To interpret and print trace data, see ACF/TAP information in ACF/TAP and trace data.