Overview
Introduction
Binary-Coded Decimal output, three hyphenated nibbles per character in this site's convention, isn't something you can eyeball back into text; each nibble needs converting to a decimal digit before the three digits combine into a character code.
This tool reverses ASCII to BCD Converter's exact format, validating every nibble along the way so a malformed or hand-edited segment gets a precise error instead of a silently wrong character.
What Is BCD to ASCII Converter?
A decoder for this site's documented BCD convention: each space-separated segment is three hyphen-joined 4-bit nibbles, each nibble a single BCD-encoded decimal digit.
It reconstructs each character's original ASCII code by reading the three digits back out of their nibbles and validates the result is a legal ASCII code (0-127) before converting it to a character.
How BCD to ASCII Converter Works
Each space-separated segment is split on hyphens into exactly 3 groups, and each group is checked to be exactly 4 binary digits representing a value 0-9 (the legal BCD digit range).
The three digits are combined back into a 3-digit decimal number; if that number is 127 or below it's converted to its character with String.fromCharCode, otherwise the segment is rejected as out of ASCII range.
When To Use BCD to ASCII Converter
Use it to read back BCD-encoded text produced by ASCII to BCD Converter, or to check whether a hand-constructed BCD segment is actually valid.
It's also useful for teaching or demonstrating exactly which nibble bit-patterns are legal BCD digits and which are not.
Often used alongside ASCII to BCD Converter, ASCII to Hex Converter and Hex to ASCII Converter.
Features
Advantages
- Validates every nibble strictly, catching invalid BCD digit patterns (1010-1111) instead of silently misinterpreting them.
- Gives a precise, positioned error identifying exactly which segment failed and why.
- Uses the exact same segment format as its encoder companion, guaranteeing a clean round trip for valid input.
Limitations
- Only understands this site's specific 3-nibble-hyphenated, space-separated segment format; BCD data formatted any other way needs reformatting first.
- Rejects any segment that decodes to a value above 127, since that's outside the ASCII range this whole encoding is built around.
Examples
Best Practices & Notes
Best Practices
- If a segment gets rejected, check for a stray extra or missing hyphen first, that's the most common cause of a malformed 3-nibble group.
- Pair with ASCII to BCD Converter to build a known-valid test segment before trying to hand-construct one.
Developer Notes
Each segment is split on "-", validated against /^[01]{4}$/ per nibble and parseInt(nibble, 2) <= 9 per digit, then recombined as `digits[0]*100 + digits[1]*10 + digits[2]` and checked against the 127 ceiling before String.fromCharCode; this mirrors ascii-to-bcd-converter's algorithm run in reverse so the two tools stay a guaranteed exact round trip for any valid input.
BCD to ASCII Converter Use Cases
- Decoding BCD-encoded text produced by ASCII to BCD Converter back into readable characters
- Validating hand-constructed or generated BCD segments for correctness before using them elsewhere
- Demonstrating which nibble bit-patterns are legal BCD digits versus invalid ones
Common Mistakes
- Passing in a nibble with a value of 10-15 (like "1011") expecting it to decode somehow; BCD has no meaning for those bit patterns and they're rejected.
- Forgetting segments are space-separated while nibbles within a segment are hyphen-separated; mixing the two delimiters up produces a malformed-segment error.
Tips
- Every valid segment has exactly two hyphens and three 4-character binary groups; a quick visual count catches most malformed input.
- Round-trip through ASCII to BCD Converter first if you want to see the exact expected format for a piece of text before hand-editing it.