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Telepen

2011-12-06
2013-02-02
  • Michael Jones
    Michael Jones
    2011-12-06

    I'm working on a project (http://bit.ly/vmhpTW) and I'd like to be able to scan barcodes so that the user can lookup bibliographic data via their mobile device. It is only a prototype, so I'll probably target a single platform initially (likely to be iOS).

    One of the barcodes I need to be able to read is Telepen. This is a propriety format established in 1972 and seems to be very popular in UK academic and public libraries. The specification and symbology is publicly available and seems fairly straight forward:

    * Represents the full ASCII character set
    * Characters take up the same amount of space
    * Wide to narrow bar ratio is 3:1
    * Four possible combinations of wide and narrow bars and spaces
    * Can be read as a binary sequence; uses 8-bit even-parity characters
    * Has a start character(_), stop character (z) and a check character

    I can look at a barcode and, with pencil and paper, work out the binary sequence to determine the barcode number. Not a great party trick :-). It would be much more useful to be able to read the barcode with ZBar.

    Looking at the code, I'm wondering where to start. I need to create a new decoder, but wondering which of the existing decoders are similar to Telepen to give me push in the right directions. Code128?

    Any pointers appreciated.