I tried to enter through the "More option", it changes the voltage, but as soon as I enter the frequency change by type "-- avalon9-freq 600:625:650:675" it does not accept the command. Tell me, am I entering data incorrectly into a string or do I need to lower the frequency in another way?
Well,
post #33 here on page 2 of this thread has a list of all A9 commands.
While you are there, that page also has results of Phil's playing with voltage-level.