Troubleshooting Terminal, Printer and Serial Device Connections - Edition 4 (32022-90030)

Chapter 4 55
TermDSM Commands
DI[AG] XI[NTERNAL]
If TermDSM knows that this test has failed, an error message will be
printed listing the reason for the failure and how many milliseconds the
test ran before failing. The diagnostics prompt will be printed and you
will be allowed to enter another subcommand.