AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE, 1968 REVISION
|----------------------------------------------------------------------|
  B  \ b7 ------------>| 0   | 0   | 0   | 0   | 1   | 1   | 1   | 1   |
   I  \  b6 ---------->| 0   | 0   | 1   | 1   | 0   | 0   | 1   | 1   |
    T  \   b5 -------->| 0   | 1   | 0   | 1   | 0   | 1   | 0   | 1   |
     S                 |-----------------------------------------------|
               COLUMN->| 0   | 1   | 2   | 3   | 4   | 5   | 6   | 7   |
|b4 |b3 |b2 |b1 | ROW  |     |     |     |     |     |     |     |     |
+----------------------+-----------------------------------------------+
| 0 | 0 | 0 | 0 | 0    | NUL | DLE | SP  | 0   | @   | P   |   ` |   p |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 0 | 0 | 1 | 1    | SOH | DC1 | !   | 1   | A   | Q   |   a |   q |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 0 | 1 | 0 | 2    | STX | DC2 | "   | 2   | B   | R   |   b |   r |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 0 | 1 | 1 | 3    | ETX | DC3 | #   | 3   | C   | S   |   c |   s |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 1 | 0 | 0 | 4    | EOT | DC4 | $   | 4   | D   | T   |  d  |   t |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 1 | 0 | 1 | 5    | ENQ | NAK | %   | 5   | E   | U   |  e  |   u |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 1 | 1 | 0 | 6    | ACK | SYN | &   | 6   | F   | V   |  f  |   v |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 0 | 1 | 1 | 1 | 7    | BEL | ETB | '   | 7   | G   | W   |  g  |   w |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 0 | 0 | 0 | 8    | BS  | CAN | (   | 8   | H   | X   |  h  |   x |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 0 | 0 | 1 | 9    | HT  | EM  | )   | 9   | I   | Y   |  i  |   y |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 0 | 1 | 0 | 10   | LF  | SUB | *   | :   | J   | Z   |  j  |   z |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 0 | 1 | 1 | 11   | VT  | ESC | +   |  ;  | K   | [   |  k  |   { |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 1 | 0 | 0 | 12   | FF  | FS  | ,   | <   | L   | \   |  l  |   | |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 1 | 0 | 1 | 13   | CR  | GS  | -   | =   | M   | ]   |  m  |   } |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 1 | 1 | 0 | 14   | SO  | RS  | .   | >   | N   | ^   |  n  |   ~ |
|---|---|---|---|------|-----|-----|-----|-----|-----|-----|-----|-----|
| 1 | 1 | 1 | 1 | 15   | SI  | US  | /   | ?   | O   | _   |  o  | DEL |
+----------------------+-----------------------------------------------+
The table, mounted on the easel before the six men at this Network Working Group meeting, was music to Homer's eyes. To Homer, it radiated order, perfection, simplicity. He knew its brevity and concision gave it artistic beauty. And now Vint Cerf, standing beside the easel, was going to explain why.

Vint seemed supremely confident as he began speaking. He always appeared in a collared and starched dress shirt with a tie, draped in a sports coat. His hearing impairment compelled him to speak loud. If you looked carefully you could see the hearing aids through his black hair. He was clean-shaven.

"This is the American Standard Code for Information Interchange. We call it 'ASCII'." He said "ass-key". "There's another system called EBCDIC. We won't use it."

Laughter pealed through Steve Crocker's thick black beard.

"Okay, Steve, there are people here who don't know why we won't. We need a uniform standard for representing characters throughout the whole ARPANET - otherwise we won't be able to communicate. Can everyone agree on that?"

Homer nodded. He looked around and found no dissent.

"Reason No. 1, LBJ has made it the official standard for all US Government computers. That means ARPA and NASA are going to expect all our work to be done in this format.

"Reason No. 2, each EBCDIC character is eight bits. An ASCII character needs only seven bits. That means, should italics ever be needed, we can just prepend an eighth bit.

"Reason No. 3, look at the table! The letters are in alphabetical order, lowercase following uppercase, and the numbers are in order too, unlike EBCDIC, where they're all jumbled up. And all you need to do to change a capital letter to lowercase is just see if the sixth bit is 0 or 1.

"Now, how do you refer to a character in the table? Take U. Fifth column, fifth row. We can also see that its ASCII binary encoding is 1010101. So we notice that the lower four bits of a character's binary encoding determine its row number, while the higher three bits decide its column number. So U would be 5/5; column first, row second."

Homer did the math in his head. 2 to the 4th is 16; that means that the column number would need to be multiplied by 16. Then you add the row number. That means an ASCII character represented by m/n is overall the (16m+n)th character in the whole character set. 16 times 5 is 80; add 5, you get 85. So U is the 85th character in ASCII. He also noticed that just by changing the sixth bit, he can make it lowercase u. He noticed that this pattern held true for all of the letters in ASCII. 2 to the 5th is 32; 85 plus 32 is 117. Not bad, he thought to himself, but everyone else can and probably has done this already.

"So that's why we should use ASCII for ARPANET. Steve, I'll have the Request for Comment by you in a few days."

"Oh great, more Xeroxing," Steve's beard parted to reveal a line of teeth.