Editing Hayes AT command set (section)

=== Syntactical definitions ===
The following syntactical definitions apply:<ref>[http://jimdgrayassoc.com/AT%20COMMANDS%20REFERENCE%20GUIDE.pdf AT Commands Reference Guide<!-- Bot generated title -->] {{dead link|date=September 2017}}</ref>
* {{code|<CR>}} Carriage return character, is the command line and result code terminator character, which value, in decimal ASCII between 0 and 255, is specified in register S3. The default value is 13.
* {{code|<LF>}} Linefeed character, is the character recognised as line feed character. Its value, in decimal ASCII between 0 and 255, is specified in register S4. The default value is 10. The line feed character is output after the carriage return character if verbose result codes are used (V1 option is used); otherwise, if numeric format result codes are used (V0 option is used), it will not appear in the result codes.
* {{code|<...>}} Name enclosed in angle brackets is a syntactical element. They do not appear in the command line.
* {{code|[...]}} Optional subparameter of a command or an optional part of AT information response is enclosed in square brackets. Brackets themselves do not appear in the command line. When the subparameter is not given in AT commands which have a Read command, the new value equals its previous value. In AT commands which do not store the values of any of their subparameters, and so have not a Read command, which are called action type commands, the action should be done on the basis of the recommended default setting of the subparameter.