After the unit powers up, you can put it into standby mode by pressing and holding the power button as you would do to shut it off, but release the button before the shut off countdown timer ends. One single press of the power button should wake it up.
I may have solved this riddle! Apparently irahy did a recent firmware update that changed the standby function. It doesn't work by using the menu like the manual says. I was told pressing the up & power simultaneously now puts the unit in standby.
If you've got one of these and the other buttons are driving you mad I also found out you now have to press the menu to wake it up and then press it again for it to take. Now not all buttons require a double tap, just the menu.
As long as you can type morse code in the dark you shouldn't have any issues running it. Good luck!