Gregor Zattler <telegraph@gmx.net> writes:

> Hi Achim,
> * Achim Gratz <Stromeko@nexgo.de> [10. Feb. 2014]:
>> You cannot enter C-: in some terminals because it would require
>> simultaneous processing of shift and control (these terminals ignore
>> shift while control is pressed).
>
> this is true for xterm, rxvt-unicode, gnome-terminal, konsole and
> the linux console.

This terminal "feature" surprised me so I checked a few terminals I have
here.

xterm on Debian (278-4) does pass the C-:.  Testing with C-c C-: after
starting "emacs -nw -q" in that xterm I get the expected:

  C-c C-: is undefined

But, I confirm that mate-terminal (1.6.1-1.1+7.wheezy) and rxvt
(1:2.6.4-14) strip off the Ctrl.  There the test produces:

  C-c : is undefined

I note that mate-terminal does process Ctrl+Shift as some of its
shortcuts use this combo.  So, it's "actively" stripping the Ctrl away.

-Brett.