In some cases, a scan beam may shine over a barcode as\nthough it was a blank paper. When the scan beam does not acknowledge a barcode,\none of two things is usually the issue:<\/p>\n\n\n\n
- The\nscan engine is not configured to decode the barcode type, or the barcode length\nis outside the minimum or maximum length specific for that barcode type, or<\/li>
- The barcode itself may be defective. Using\nanother type of device to try and read the barcode is usually the best way to\nsee if a barcode is valid. Most modern smart phones can download a free\napplication to recognize barcodes and decode their contents.<\/li><\/ol>\n\n\n\n
Within StayLinked \u2013<\/strong>\nMaking adjustments to data can be configured for all devices, or groups of\ndevices with one or more rules. StayLinked supports adjustments to barcode data\nin three different places. In areas 1 and 2 below, the adjustments are specific\nto a barcode symbology. You can confirm what StayLinked receives as the\nbarcode type by using the StayLinked Client Scan Test as mentioned above. The\nthree areas for barcode adjustments in StayLinked include:<\/p>\n\n\n\n
- Telnet\nHost Entry \u2013 When you configure the rules for communicating with a telnet host,\nyou can select the Manage pulldown menu from the top of the screen to set\nbarcode rules that apply only to that telnet host.<\/li>
- Device Groups \u2013 Rules added to the device group\nhave priority over settings in the telnet host. This allows you to create\nglobal rules in the host entry, and then exceptions in the individual groups\nthat require special adjustments.<\/li>
- Screen Recognition \u2013 These features can be used\nto apply \u2018Input Modifiers\u2019 to specific screens or fields. More information on\nInput Modifiers can be found in the SmartTE and Screen Recognition User\u2019s\nGuide. <\/li><\/ol>\n\n\n\n
All three of these locations support the use of regular\nexpressions. Several common configuration options, such as trimming spaces,\nreplacing certain characters and prefix\/suffix additions can be made in the\nbasic configuration dialogues. More complicated adjustments may require the use\nof regular expressions. More information on regular expressions can be found in\nthe Regular Expression Guide, or using online materials. These expressions make\nup a simplified syntax for identifying patterns and returning the desired\nresults.<\/p>\n\n\n\n
At the Hosted Application \u2013 <\/strong>Some hosted applications may track data or restrict input based on barcode data. One example would be the use of a prefix character on barcodes that cannot be typed. When this character appears at the beginning of a barcode, the host application can strip the character off and then proceed with the transaction with the confirmation that the data has been scanned. Special prefixes may also be used to identify the type of barcode scanned, helping to eliminate the entry of incorrect barcodes into the hosted application.<\/p>\n\n\n\n
Special Characters in Barcodes<\/h3>\n\n\n\n
Some symbologies such as GS1 can display a bracket character at the beginning of each barcode. Bracket characters are processed by StayLinked as part of a mnemonic. These mnemonics, like [enter] and [tab] perform a function instead of simply typing the word into the application. These mnemonic examples would perform [enter] as a Carriage Return and Line Feed (0x0A0D) or a tab key (0x09). <\/p>\n\n\n\n
![\"\"](\"https:\/\/portal.staylinked.com\/sl\/kb\/wp-content\/uploads\/2019\/08\/Add-new-Barcode.jpg\")
<\/figure><\/div>\n\n\n\nSingle brackets are treated as a\nfailed mnemonic, preventing the barcode data from being submitted to the hosted\napplication by the StayLinked Server. The barcodes would appear in the\nStayLinked Client Scan Test, but the server-side test would show the issue in\nthe Translation. Double brackets are translated as a single. The adjustment can\nbe made in the scan engine, or at the StayLinked Server as mentioned above. The\nmost common setting to allow the bracket character to the host application\nwould be a substitution of the single bracket to a double bracket as shown here\nto the right.<\/p>\n\n\n\n
Tab Characters can sometimes be\nentered in concatenated barcodes to split one barcode across multiple fields of\ndata. This may work in 5250 because of the block-mode nature of the emulation.\nVT emulation does not contain actual fields, and involves some amount of\nprocessing between changes in displayed input location. This means VT can only\nparse the data across input entries if the host can process each input fast\nenough to keep up, or can store the data as it is entered for the forthcoming\ninput prompts.<\/p>\n\n\n\n
Some barcodes can include embedded control codes. These codes are passed on to the host application as part of the input string, but may cause the host issues if it is not prepared to handle the events. These control codes can be globally replaced in the barcode rules above by setting the replacement character. The replacement can be a standard printable character or a simple NULL value 0x00. Control codes adjusted by this setting are any value in hexadecimal below 0x20. 0x20 and codes above will not be affected by this option.<\/p>\n\n\n\n
Symbology Identifiers and scanner.ini<\/h3>\n\n\n\n
Devices that require scanner\nconfiguration may provide an option for a symbology identifier. This value\ntells the program what type of barcode has been scanned. Without this option,\nall barcodes may be reported as a barcode type of Unknown\/Unsupported. It is\nalways important to make sure any barcode rules are applied to the correct\nsymbology type and will not adversely affect barcodes used on other screens, of\ndifferent lengths, or barcode that contain different types of data.<\/p>\n\n\n\n
Devices that require customization of these symbology identifiers can use a custom configuration file called scanner.ini. More information on this configuration file can be found in the StayLinked Client User Guide for the correct version of your StayLinked Client.<\/p>\n\n\n\n
Beep on Bad Scan Inputs<\/h2>\n\n\n\n
Only the host application knows what a correct or invalid barcode might look like. Everything in the communication chain prior to the host application simply acts as a transport. You can 'teach' StayLinked when to look for specific screen contents, but it's not a simple option and would need to be done for every desired screen.<\/p>\n\n\n\n
This means you can use Screen Recognition <\/a>features that trigger a beep when an error message is painted to the screen.<\/p>\n\n\n\n