user51300: I'm working on an RS485 project, In the CPP file there are const variables declared in the following manner: 
#include <RS485_protocol.h>
const byte STX = '\2'; 
const byte ETX = '\3';

What does the '\2' and '\3' mean?

user37622: The '\2' and '\3' are characters with octal code 2 and 3. Which is nothing more then 2 and 3 in octal and in decimal. The author could simply write const byte STX = 2; const byte ETX = 3;.
Characters with ASCII code 2 and 3 are control characters STX (start of text) and ETX (end of text). Control characters are invisible characters used to control the terminal or as mark characters in communication.

51300: <p>I'm working on an RS485 project, In the CPP file there are <code>const</code> variables declared in the following manner: </p>

<pre><code>#include &lt;RS485_protocol.h&gt;
const byte STX = '\2'; 
const byte ETX = '\3';
</code></pre>

<p>What does the '\2' and '\3' mean?</p>
 37622: <p>The '\2' and '\3' are characters with octal code 2 and 3. Which is nothing more then 2 and 3 in octal and in decimal. The author could simply write <code>const byte STX = 2; const byte ETX = 3;</code>.</p>

<p>Characters with ASCII code 2 and 3 are control characters STX (start of text) and ETX (end of text). Control characters are invisible characters used to control the terminal or as mark characters in communication.</p>
