US-ASCII hex codes
characters 00..1f and 7f are control characters
characters 20..7e are graphic characters

00 NUL    10 DLE    20 SPACE  30 0      40 @      50 P      60 `      70 p
01 SOH    11 DC1    21 !      31 1      41 A      51 Q      61 a      71 q
02 STX    12 DC2    22 "      32 2      42 B      52 R      62 b      72 r
03 ETX    13 DC3    23 #      33 3      43 C      53 S      63 c      73 s
04 EOT    14 DC4    24 $      34 4      44 D      54 T      64 d      74 t
05 ENQ    15 NAK    25 %      35 5      45 E      55 U      65 e      75 u
06 ACK    16 SYN    26 &      36 6      46 F      56 V      66 f      76 v
07 BEL    17 ETB    27 '      37 7      47 G      57 W      67 g      77 w
08 BS     18 CAN    28 (      38 8      48 H      58 X      68 h      78 x
09 HT     19 EM     29 )      39 9      49 I      59 Y      69 i      79 y
0a LF     1a SUB    2a *      3a :      4a J      5a Z      6a j      7a z
0b VT     1b ESC    2b +      3b ;      4b K      5b [      6b k      7b {
0c FF     1c FS     2c ,      3c <      4c L      5c \      6c l      7c |
0d CR     1d GS     2d -      3d =      4d M      5d ]      6d m      7d }
0e SO     1e RS     2e .      3e >      4e N      5e ^      6e n      7e ~
0f SI     1f US     2f /      3f ?      4f O      5f _      6f o      7f DEL