The 'master'-switch for starting and stopping the AST generating data output is the 'run'-bit; writing a 1 to address location RUN starts the AST (enables run), a 0 (zero) stops the AST (disables run).
The AST can be stopped at any time; it will finish sending the current token and then stop; when enabled again it will resume sending data immediately if none of the other stop conditions are satisfied.
Run can also be enabled by a NIM-pulse (or TTL; this can be set with a jumper), for which a connector is provided on the frontpanel of the AST; note that run can NOT be disabled by a NIM-pulse: disabling is done by a control token when in event mode, or explicitly by the VME-master.
When the event mode is enabled every control token sent by the AST will disable run; to continue it has to be enabled again by the VME-master or through the NIM-input.