Below is a table listing all the non-printable ASCII characters.

DEC HEX CHARACTER
0 0 NULL
1 1 START OF HEADING (SOH)
2 2 START OF TEXT (STX)
3 3 END OF TEXT (ETX)
4 4 END OF TRANSMISSION (EOT)
5 5 END OF QUERY (ENQ)
6 6 ACKNOWLEDGE (ACK)
7 7 BEEP (BEL)
8 8 BACKSPACE (BS)
9 9 HORIZONTAL TAB (HT)
10 A LINE FEED (LF)
11 B VERTICAL TAB (VT)
12 C FF (FORM FEED)
13 D CR (CARRIAGE RETURN)
14 E SO (SHIFT OUT)
15 F SI (SHIFT IN)
16 10 DATA LINK ESCAPE (DLE)
17 11 DEVICE CONTROL 1 (DC1)
18 12 DEVICE CONTROL 2 (DC2)
19 13 DEVICE CONTROL 3 (DC3)
20 14 DEVICE CONTROL 4 (DC4)
21 15 NEGATIVE ACKNOWLEDGEMENT (NAK)
22 16 SYNCHRONIZE (SYN)
23 17 END OF TRANSMISSION BLOCK (ETB)
24 18 CANCEL (CAN)
25 19 END OF MEDIUM (EM)
26 1A SUBSTITUTE (SUB)
27 1B ESCAPE (ESC)
28 1C FILE SEPARATOR (FS) RIGHT ARROW
29 1D GROUP SEPARATOR (GS) LEFT ARROW
30 1E RECORD SEPARATOR (RS) UP ARROW
31 1F UNIT SEPARATOR (US) DOWN ARROW