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    wiegand-encoder
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    1.1.2 • Public • Published

    wiegand-encoder

    Lightweight module that encodes and decodes 26, 34, or 38 bit Wiegand protocol credentials for communication with access control systems.

    ci coverage npm license

    Installation

    npm install wiegand-encoder

    Usage

    // Modules
    import wiegand from 'wiegand-encoder';
    
    // CommonJS
    const wiegand = require('wiegand-encoder');

    Encoding

    The encode() function converts a card number and facility code into binary, counts the bit parity of each half of the message, and wraps it in parity bits.

    const encoded = wiegand.encode(cardNumber, facilityCode);
    
    wiegand.encode(wiegand.encode(324, 90));
    // 00101101000000001010001000

    If the specified card number or facility code are too high for the standard bit length, it will throw an exception. The largest possible card number in 26-bit protocol is 65535, and the largest possible facility code is 255.

    Decoding

    The decode() function validates the parity bits on either side of the message, then parses the message content from binary back into integers.

    const { cardNumber, facilityCode } = wiegand.decode('00101101000000001010001000');
    // { cardNumber: 324, facilityCode: 90 }

    If the parity bits are invalid, decode() will throw an exception.

    To check parity on a message without decoding it, use parity.validate().

    try {
      wiegand.parity.validate('00101101000000001010001000');
    } catch (error) {
      console.error(error);
    }

    Alternate bit length

    By default, encode() encodes all messages as 26-bit.

    To encode a larger message (e.g. 34-bit, 38-bit, etc.) send the bit length for the card number and facility code to the encode() function.

    26-bit credentials use a card number length of 16 and a facility code length of 8. To encode a 34-bit message, use a card number length of 22 and a facility code length fo 10.

    wiegand.encode(cardNumber, facilityCode, cardNumberLength, facilityCodeLength);
    
    wiegand.encode(wiegand.encode(324, 90, 22, 10));
    // 0000101101000000000000001010001000

    The decode() function also supports optional cardNumberLength and facilityCodeLength parameters, but will attempt to infer them based on the content of the length of the message if omitted.

    const { cardNumber, facilityCode } = wiegand.decode('0000101101000000000000001010001000');
    // { cardNumber: 324, facilityCode: 90 }

    License

    MIT © Jesse Youngblood

    Install

    npm i wiegand-encoder

    DownloadsWeekly Downloads

    116

    Version

    1.1.2

    License

    MIT

    Unpacked Size

    20.8 kB

    Total Files

    12

    Last publish

    Collaborators

    • jessety