To get somewhat techy, STX or Start of Text is represented in hex as 02. Panasonic uses 02h to define it and RTI uses \x02. The same is true for ETX or End of Text using 03.

There are several ways to represent the same thing in serial. For example:
ascii character 1 (on a keyboard) is equal to
hex 31
hex can be seen as 02h, \x02, 0x02 plus several more
decimal 49
decimal can be seen as 049, \d049
oct 61
html & # 49 ; without the spaces
binary 110001
binary is how the electonic pulses are actually sent

It just depends on what language it is documented in. Some maufacturers use strictly ascii, some use only hex, or in Panasonic's case a mixture. It all sends the same 1's and 0's in the end.