Read-Ahead Bar Code Data Access; Grid Data Filtering - Intermec 700 Series User Manual

Scanner Support

Read-Ahead Bar Code Data Access

The Bar Code Reader COM object delivers ADC data to the connection in read-
ahead mode. In this mode, the data is queued until a COM connection is ready
to read it. Read-ahead mode decouples reader device performance from the ap-
plication performance. That is, data is read as fast as the user can scan it, inde-
pendent of the connection processing load. No data will be scanned until the first
Read() function is posted.

Grid Data Filtering

The virtual wedge retrieves scanned Automatic Data Collection (ADC) data and
sends it to the keypad driver so that the 700 Series Computer can receive and
interpret the data as keypad input. The data can be filtered so that only data
conforming to a certain text pattern or symbology will be sent to an application.
After the data is filtered, it can be edited by adding, deleting, or rearranging por-
tions of the text or by extracting portions of text for further editing. To filter and
edit data, you need to define the virtual wedge grid parameters.
Grid Processing:
Syntax:
6-4 700 Series Color Mobile Computer User's Manual
Grid processing takes place in two steps:
Compilation:
In which the user's grid expressions are checked for errors and reduced
to a binary form for faster matching. This is done whenever the virtual
wedge grid is set or changed by configuration software.
Matching:
In which data is tested against the grids set in compilation. Matching
can be performed multiple times after a compilation. The AIM
symbology ID of the data being tested, including the enclosing
angle brackets, must be prepended to the incoming data.
The basic syntax of each grid expression is:
<symID> filter-expression= > editing-expression
symID
Is the AIM symbology ID (see the AIM Symbology ID Defaults table
starting on page 6-63).
filterexpression
Is any character string that includes valid filter expression values
(see the "Filter Expression Values" table below).
editing-expression
Is any character string that includes valid editing expression values
(see the "Editing Expression Values" table on page 6-6).
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