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Using ubuntu, and mathematica 11.1, the keyboard shortcut ctrl+g creates a small emoji of an old landline phone (see image). It does not appear in mathematica 10. If I copy it from 11.1 end up with the string "\.07" in my clipboard.

It can not be set equal to anything, I get the error message:

Syntax: Expression cannot begin with ... = 5

It also doesn't seem to be useable in any function, I get the error message: 

Syntax: f[...] is incomplete; more input is needed.

where the ... is the symbol.

It doesn't seem to appear in the Keyboard Shortcut Listing, the List of Special Characters, the List of Letters and Letter like Forms. I also can't find anything about it on stackexchange.

Does anyone know what this thing is, and why it was given this shortcut? It seems rather mysterious to me (and my colleague who originally found it)!

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    $\begingroup$ Looks to me like Unicode U+260E. You can input it manually by typing \:260E. I don't know why it's mapped to Control-G - perhaps an idiosyncrasy of your OS setup? $\endgroup$
    – Carl Lange
    Jan 22, 2019 at 15:36
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    $\begingroup$ @CarlLange It seems somewhat different to that, I can enter U+260E (e.g. by copying and pasting it from somewhere) and it acts as a "normal" symbol (e.g. ☎ = 5 works). On the other hand setting the thing I get from crtl-g equal to 5 does not. Edit: the symbol is also different see image, the left is the ctrl-g thing, and the right is U+260E. $\endgroup$
    – or1426
    Jan 22, 2019 at 15:39
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    $\begingroup$ Doesn't do anything on 11.3 on MacOS. I note that in ancient times Control-G stood for the character code 7, which rang the bell on your teletype. $\endgroup$
    – John Doty
    Jan 22, 2019 at 15:55
  • $\begingroup$ To add to John Doty's comment, here's an old ASCII chart from Wikipedia; look for BEL: upload.wikimedia.org/wikipedia/commons/c/cf/… $\endgroup$
    – Michael E2
    Jan 22, 2019 at 18:17
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    $\begingroup$ @JohnDoty This brings back memories! I'm not old enough to have used those things professionally, but I had old teletypes (printing on paper) with physical bell as a kid in the mid-eighties, the sort you found inside rotary telephones, for Ctrl-G. Sadly enough I think all of them are now dismantled. $\endgroup$
    – kirma
    Jan 22, 2019 at 20:17

1 Answer 1

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Rephrasing comments:

It's an ASCII BEL (bell) control code character. Teletypes and at least some computers had a physical, solenoid-driven electric bell in them up to like early eighties, as it was probably the technically cheapest way to implement an audio indication those days. They were pretty much the same technology as bells used on rotary dial phones at the same period, although a BEL character usually resulted just a single stroke, not a continuous ring.

Original BEL character had no visual appearance, only audible one. Apparently someone has chosen to visualise it on Ubuntu as a phone symbol...

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