5-Bit Binary Code Translator

Choose A1Z26 when the source numbers A–Z as 1–26; choose ITA2 when the source specifies the supported international teleprinter mapping. The same bits have different meanings: 00001 is A in A1Z26 but E in ITA2 Letters state using numeric display. Five-bit length alone does not identify an alphabet.

• Compare the two mappings

00101 is E in this site's A1Z26 teaching scheme, or S in international ITA2 Letters state with numeric bit order. As an unsigned integer, it is simply 5. An ITA2 answer also depends on the current shift state and bit order, so include those assumptions rather than calling E the universal binary meaning.

• Compare short-sequence interpretations

Five bits provide 32 values. ITA2 uses Letters and Figures states to reuse some values for letters, digits, and punctuation. In numeric display, 11011 switches to Figures and 11111 switches to Letters without printing a character. A1Z26 does not use these shifts; values above 26 are invalid in this site's A1Z26 decoder.

• Follow a Letters/Figures example

Each ITA2 decode starts in Letters state. Encoding emits an initial Letters shift, 11111, to make that starting state explicit, then inserts shifts as needed. The shift is not a printable letter. If your source is an excerpt captured during Figures state, its missing earlier shift must be established from context rather than guessed.

• Check how shifts are emitted

Numeric display puts the most significant bit first. Serial display lists transmission element 1 first, reversing the digits within each five-bit group without reversing the groups themselves. For ITA2 E in Letters state, numeric 00001 becomes serial 10000. Match the source's order before decoding; this setting does not select a different alphabet.

• Compare numeric and serial examples

This site's A1Z26 mode reserves 00000 for a space, which is a local teaching convention. In ITA2, 00000 is NUL and prints nothing; numeric 00100 is a space. An ITA2 space does not reset the current shift state here. Decoding continues in Figures or Letters until an explicit shift changes it.

• Review mapping and state differences
• Trace the shift state

A1Z26 accepts A–Z and spaces and converts lowercase to uppercase; digits and punctuation are rejected. ITA2 also converts lowercase to uppercase and supports the digits and punctuation defined by its international mapping. Neither option supports arbitrary Unicode text. Use UTF-8 for accented letters, Chinese, emoji, or text whose original letter case must be preserved.

• Check supported five-bit data
• Encode Unicode text

Yes. Both five-bit decoders accept a continuous stream or groups separated by whitespace and commas. After separators are removed, the bit count must be divisible by five. A trailing short group is an error, not permission to pad with zeroes. Check the original source for missing digits before trying again.

• Understand the risks of padding

This tool follows international ITA2 in ITU-T S.1 (03/93), Table 1, and rejects national/private Figures assignments instead of choosing a local meaning. Charts labelled Baudot may use a different historical or national mapping. Compare the chart's variant, shift state, and bit order before treating a disagreement as a conversion error.

• Review the supported ITA2 variant
• View sources and verification

No. The tool accepts already-extracted five-bit data groups, not audio, radio signals, baud timing, or start/stop framing. A complete signal needs those layers decoded first using its documented settings. Once you have the data bits, select the supported ITA2 mapping and bit order; do not include framing bits as if they were character data.

• Check five-bit input boundaries