Something

	for					(i=0; i<strlen(t_c_str); i=i+2){									/* i = i + 2 */
		f_substr		(t_hex_to_char, t_c_str, i, i+1+1);									/* get the 2 byte hex */
		hex_to_char_num = f_hex_to_int(t_hex_to_char);										/* convert the hex to an interger */
		c_rtn[(i/2)]	= hex_to_char_num;													/* convert the integer to a character */
		c_rtn[(i/2)+1]	= '\0';																/* convert the integer to a character */
	}