Call me stupid 
, but just how do you enter the ctrl-z on the end of your message for the at+cmgs= … command in the AT Console window, other than by copy-pasting the corresponding character in the console output resulting from a message sent from the main GUI?
Hi Mark,
First, there is neither stupid question, nor stupid guy ! 
There is indeed no “native” way to add a character currently in the text field of the AT Console window. You guess the only way was to copy/paste the character from a similar command sent from the UI.
We will try to see how we can fix this in a future release, and we already guess, is not the only special character. The character must also be managed in the text field, to abort the CMGS command for example.
Regards,
Jacques
Ctrl-Z character is now supported, and will be available in the next version 1.1 planned for mid-October. Stay tuned !