Baudot Data Communication Code |
Data are communicated between digital computers as sequences of bits. To provide meaning to a sequence of bits, the bits are grouped to form a data character and an encoding scheme, or translation table, is provided to allow a computer system to translate each group of bits into a character. The ideal encoding scheme will provide a unique code for every possible character to be communicated and stored in the computer, but this requires that each group have a sufficient number of bits for each data character.
A code used early in the data communications industry is the Baudot code. Baudot uses five bits per character, thus allowing up to 32 distinct characters. As a technique used to extend this limitation, the code uses up-shift and down-shift modes as is used on a typewriter. In the Baudot code, each five bits transmitted must be interpreted according to whether they are up-shifted (figures) or down-shifted (letters). For example, the bit pattern 11111 represents up-shift and the bit pattern 11011 represents down-shift characters. All characters transmitted after the sequence 11111 but before the shifted sequence 11011 are treated as up-shift characters. All characters transmitted after the sequence 11011 are treated as down-shift characters until the pattern 11111 is recognized. The complete BAUDOT code (modified for this problem) is shown in the table at the end of this problem.
The input file will be terminated by end-of-file. The initial state of each message should be assumed to be in the down-shift state.
<T*O HNM=LRGIPCVEZDBSYFXAWJ UQK >5@9 %,.+)4&80:;3"$?#6!/-2' 71( 100100110011000010011111101110000111110111101 001100001101111001001111100001001100010001100110111100000111
DIAL:911 NOV 5, 8AM
Bit Pattern | Down-Shift Character | Up-Shift Character |
00000 | < | > |
00001 | T | 5 |
00010 | * | @ |
00011 | O | 9 |
00100 | Space | Space |
00101 | H | % |
00110 | N | , |
00111 | M | . |
01000 | = | + |
01001 | L | ) |
01010 | R | 4 |
01011 | G | & |
01100 | I | 8 |
01101 | P | 0 |
01110 | C | : |
01111 | V | ; |
10000 | E | 3 |
10001 | Z | " |
10010 | D | $ |
10011 | B | ? |
10100 | S | # |
10101 | Y | 6 |
10110 | F | ! |
10111 | X | / |
11000 | A | - |
11001 | W | 2 |
11010 | J | ' |
11011 | Shift Down | Shift Down |
11100 | U | 7 |
11101 | Q | 1 |
11110 | K | ( |
11111 | Shift Up | Shift Up |
Table: The BAUDOT code