CTRL, 1 – Mutes Windows Sound?!?!

Is this a standard???  I can’t find reference to this hot key sequence out there in Google land. You need to hit CTRL, release and then hit 1, not CTRL-1, i.e don’t hold down CTRL. On my (*non* Windows Media Keys Keyboard under Windows 7) system here, it works with both left and right CTRL and main keyboard or numeric keyboard “1”.   Google Keywords: Windows 7, Audio, Mute, Volume, Control, CTRL, 1, One