Thursday, May 29, 2014

Barcode Scanner Issue

One of the first issues we have encountered this summer was with our barcode scanners.  Kudos goes out to Matt S, the Informatics Assistant for resolving the issue.  See his communication below:


In our library, we use a bunch of MS 9520 Voyager barcode scanners.  In general, these are fantastic, reliable scanners and we have not had any fail. 
Recently though, we have had some interesting problems as the barcode scanner has randomly read only part of the barcode on an item.
This is what our Circulation department discovered:
“Just wanted to inform you all of another barcode scanning error involving a set of headphones.  We were alerted of the issue today because the book that was erroneously charged was generating overdue notices and the patron came in to ask about it.

The actual charge happened on April 30 at 7:54pm.  The book that was charged has an accession number of 8XXXX.  At the same time my reports show the book being charged, the headphones with barcode 4000000008XXXX were also charged.  (Last five digits of the barcode match the book’s accession number.)  The time stamps are the same down to the second—7:54:27pm.  This makes me think that perhaps nothing even popped up in Voyager to indicate that the book was charged.  This particular set of headphones has been charged 123 times and this is the first time this book was charged as well.  So it’s definitely not consistent.

In previous communications I’ve had with our library consortium, I’ve heard that some scanners allow for setting a fixed code length.  I’m not sure we can have a fixed length because our item barcodes are 14-digits and our ID card barcodes are 12-digits.  But do you know if any settings exist that would allow us to set a minimum length (i.e., greater than or equal to 12 digits)?  I just can’t wrap my head around the irregular nature of these incorrect scans.  From what I’ve documented, this appears to be the 7th instance of this in the past two and a half years.  Any ideas you might have would be welcome.”

While relatively infrequent, these errors are a nuisance and I decided to set out to find a way to set the minimum barcode scanning length to 12 digits.

I started with a Google search and turned up nothing so I then decided to consult the rather thick manual that came with our 9520 scanners.  After pouring through the manual, I found a section ambiguously entitled “Additional Decode Features” which outlined instructions to set a minimum symbol (or barcode) length.  My excitement was quickly dampened when the instructions for setting a minimum length made little sense.  The instructions were not clear and they incorrectly referenced the location of additional necessary configuration information in the manual.  After more searching through the manual, I finally found what I needed and tried to decipher the required steps.
Essentially, the configuration process requires that you:
1. Scan the “configuration mode” barcode at the beginning of the manual
2. Scan the barcode to enter the minimum symbol length mode
3. Scan barcodes for “code bytes” the set the minimum symbol length
4. Scan the configuration mode barcode one last time

The problem was that the code bytes section, which provided no instructions, made it look like I had to figure out the hexadecimal equivalent for our minimum barcode length.  I kept on going through the prior instructions to figure that out and was about to give up when I decided to ask one of our programmers, Ian, for his perspective.  After looking through it for a few minutes, Ian realized that I had over-thought it and said that the code bytes simply stood for digits.  Could it really be that simple? 
Indeed it was.
I tried it over again and in step three, I scanned the byte that corresponded with 0, then 1, then 2, equating to a minimum length of 12.
I finished the process and scanned some test barcodes that I had printed and VOILA, it worked!  Anything less than 12 digits simply does not scan now.

Now we will get to see if this solves this random problem for us. 

-Matt S

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