BinOctDecHexChrEnt
0000 0000000NUL (NULL)�
0000 0001111SOH (Start of Heading)
0000 0010222STX (Start of Text)
0000 0011333ETX (End of Text)
0000 0100444EOT (End of Transmission)
0000 0101555ENQ (Enquiry)
0000 0110666ACK (Acknowledge)
0000 0111777BEL (Bell)
0000 10001088BS (Backspace)
0000 10011199HT (Horizontal Tabulation)	
0000 10101210ALF (Line Feed)

0000 10111311BVT (Vertical Tabulation)
0000 11001412CFF (Form Feed)
0000 11011513DCR (Carriage Return)
0000 11101614ESO (Shift Out)
0000 11111715FSI (Shift In)
0001 0000201610DLE (Data Link Escape)
0001 0001211711DC1 (Device Control 1)
0001 0010221812DC2 (Device Control 2)
0001 0011231913DC3 (Device Control 3)
0001 0100242014DC4 (Device Control 4)
0001 0101252115NAK (Negative Acknowledge)
0001 0110262216SYN (Synchronous Idle)
0001 0111272317ETB (End of Transmission Block)
0001 1000302418CAN (Cancel)
0001 1001312519EM (End of Medium)
0001 101032261ASUB (Substitute)
0001 101133271BESC (Escape)
0001 110034281CFS (File Separator)
0001 110135291DGS (Group Separator)
0001 111036301ERS (Record Separator)
0001 111137311FUS (Unit Separator)
0010 0000403220 (Space) 
0010 0001413321!!
0010 0010423422""
0010 0011433523##
0010 0100443624$$
0010 0101453725%%
0010 0110463826&&
0010 0111473927''
0010 1000504028((
0010 1001514129))
0010 101052422A**
BinOctDecHexChrEnt
0010 101153432B++
0010 110054442C,,
0010 110155452D--
0010 111056462E..
0010 111157472F//
0011 000060483000
0011 000161493111
0011 001062503222
0011 001163513333
0011 010064523444
0011 010165533555
0011 011066543666
0011 011167553777
0011 100070563888
0011 100171573999
0011 101072583A::
0011 101173593B;&#59;
0011 110074603C<&#60;
0011 110175613D=&#61;
0011 111076623E>&#62;
0011 111177633F?&#63;
0100 00001006440@&#64;
0100 00011016541A&#65;
0100 00101026642B&#66;
0100 00111036743C&#67;
0100 01001046844D&#68;
0100 01011056945E&#69;
0100 01101067046F&#70;
0100 01111077147G&#71;
0100 10001107248H&#72;
0100 10011117349I&#73;
0100 1010112744AJ&#74;
0100 1011113754BK&#75;
0100 1100114764CL&#76;
0100 1101115774DM&#77;
0100 1110116784EN&#78;
0100 1111117794FO&#79;
0101 00001208050P&#80;
0101 00011218151Q&#81;
0101 00101228252R&#82;
0101 00111238353S&#83;
0101 01001248454T&#84;
0101 01011258555U&#85;
BinOctDecHexChrEnt
0101 01101268656V&#86;
0101 01111278757W&#87;
0101 10001308858X&#88;
0101 10011318959Y&#89;
0101 1010132905AZ&#90;
0101 1011133915B[&#91;
0101 1100134925C\&#92;
0101 1101135935D]&#93;
0101 1110136945E^&#94;
0101 1111137955F_&#95;
0110 00001409660`&#96;
0110 00011419761a&#97;
0110 00101429862b&#98;
0110 00111439963c&#99;
0110 010014410064d&#100;
0110 010114510165e&#101;
0110 011014610266f&#102;
0110 011114710367g&#103;
0110 100015010468h&#104;
0110 100115110569i&#105;
0110 10101521066Aj&#106;
0110 10111531076Bk&#107;
0110 11001541086Cl&#108;
0110 11011551096Dm&#109;
0110 11101561106En&#110;
0110 11111571116Fo&#111;
0111 000016011270p&#112;
0111 000116111371q&#113;
0111 001016211472r&#114;
0111 001116311573s&#115;
0111 010016411674t&#116;
0111 010116511775u&#117;
0111 011016611876v&#118;
0111 011116711977w&#119;
0111 100017012078x&#120;
0111 100117112179y&#121;
0111 10101721227Az&#122;
0111 10111731237B{&#123;
0111 11001741247C|&#124;
0111 11011751257D}&#125;
0111 11101761267E~&#126;
0111 11111771277FDEL (Delete)&#127;
Ascii defines 128 characters ranging from 0 to 127, which utilizes 7 bits. A byte is 8 bits.
Ascii is defined in rfc 20 at http://tools.ietf.org/html/rfc20.

Regarding letters, if bit 6 (value 32) is turned on then the letter is in lowercase.