9.2.5.3 Strings

Strings may be given in one of two formats.

  • ASCII with the facility for special characters (for example, tab, carriage return, line feed) to be specified via escape sequences. ASCII strings must be enclosed in double quotes (”).
  • Hexadecimal string, a stream of two-digit hexadecimal values. Hexadecimal strings must be enclosed within square brackets ([ ]).
    Note: Each byte being transferred must be specified using two digits - for instance the byte value ‘2’ must be represented ‘02’.

In the case of an ASCII string, the following characters will be escaped:

Description Characters

Horizontal Tab

\t

Backslash

\\

Double Quotes

\"

Carriage Return

\r

Linefeed

\n

Terminal Bell

\a

Backspace

\b

Vertical Tab

\v

Form feed

\f

Escape

\e

Examples:
  • “hello” – ASCII string representation of hello
  • “\r\nNew line” – ASCII string representation of <CR><LF>New line
  • [68656c6c6f] – Hex string representation of hello

An empty string will be represented as either an empty ASCII string (””) or an empty hexadecimal string ([]). Both representations are valid and equivalent for input, for output only the ([]) form will be used.