We have a series of buttons in our administrative interface, for turning systems online or offline (context-sensitive). Currently these buttons are simply either blue "Online" buttons to bring a system online or red "Offline" buttons to bring a system offline.
However, I find the buttons a bit ambiguous; does a blue "Online" button mean it's Online and the button will turn it off, or does it mean clicking the button will bring it online? The matter is made worse by the fact that there are a large number of systems, so the individual lines are small, and the text is difficult to read. Compounding this, one of my coworkers is colorblind, and the somewhat distinguishable (to me) red and blue is lost on him and he's left to squint at the small text.
There is also an online/offline status column (which helps somewhat) to clarify the button's meaning, but then there's the issue of "which is the button and which is the indicator again?". This indicator suffered a similar problem, just stating "Online" or "Offline", using a green/red color scheme (which is even worse for my colorblind coworker).
I used TamperMonkey to fix the indicator, which now presents a very obvious dark green checkmark on light background for "online", or a white "X" in a filled bright red circle for "offline" (so it's using shape, background reversal, color, and intensity to differentiate). However, I'd like to change the buttons so their meaning is just as unambiguous and easy to determine at a glance.
Is there any sort of "standard" means of indicating the action of turning something on or off, or can someone recommend something that's easily intuitive and immediately distinguishable? I'd like something that conveys a change of state, perhaps with an arrow or the like.
Here are the original indicators (pre-userscript):
Here's the current state of our indicators, as a reference (post-userscript, with the check and "X" being my modifications):
(Note that I screenshotted a different set of indicators, so they appear reversed between the two screenshots. In both shots, the line that has the blue "Online" button is currently offline, and the line that has the red "Offline" button is currently online)