Types of Data Collection
Bar code data-collection systems fall into
three basic types: interactive, batch, and hybrid.
- An interactive system
consists of one or more portables connected in real time
to a computer. In these systems, the central computer
manages data collection and verification as the user
- A batch system
uses one or more portables to gather data that is stored
for later input to a computer. This is the most common
and most economical portable system. Batch systems can do
only limited validity checking.
- A hybrid system
is a combination of the two.
Interactive systems have several advantages
over batch systems. Almost all systems where bar code hardware is
in a fixed location are interactive systems. Advantages include:
- Immediate Data
Verification: As the user enters data, the
computer can check its validity and give the user
variable responses depending on that validity.
- Sophisticated Data
Verification: An interactive system can
check many more variables when performing data
verification. For example, a batch system can check the
status of a part number only against the last part
numbers that were sent to the portable. An interactive
system can check the status of a part number against the
entire inventory at any time.
- User Interaction:
Interactive systems can give the user better feedback
when an error occurs. Since the system can check more
variables, you can tailor the responses given to the user
to solve problems.
- Error Reduction:
All of the above advantages tend to reduce errors in an
interactive system. This reduces the labor cost to
correct the errors, as well as the consequences of acting
on incorrect data.
- Easy Setup:
Interactive systems use standard programming techniques
and error checking, much like programming for PCs. You
can process each transaction and verify data in real
time. Batch processing requires a way to process data in
batches and a mechanism for correcting errors after the
Batch systems are generally used with
portable readers. They are also used in some fixed-mount systems
where the reader must continue to collect data if the computer
system goes down. While interactive systems are superior in the
ways listed above, batch systems do have some advantages:
- Economical for Standard
Portables: Portables can be used for batch
or real-time applications. Real-time applications require
a costly radio frequency (RF) network. On average, setup
costs for batch systems are less than half the costs of
- Reliable in
Mission-Critical Applications: Since batch
processing distributes data collection to stand-alone
units, operation is not dependent on the central
computer. If a particular unit fails, it can be replaced.
If the central computer fails, data collection can
Several systems combine attributes of both
interactive and batch modes. The most common are radio frequency
systems and batch/interactive hybrids.
Radio frequency systems
use RF signals to connect portable readers to a central computer
in an interactive manner. This gives the advantages of an
interactive system combined with portability. There are different
types of RF:
- The simplest RF bar code device is a
portable scanner that communicates with a single receiver
connected to a computer or terminal.
- Another type of RF system connects a
portable to a typical computer network through an RF
access point. This has many advantages, such as the
ability to "roam" from one access point to
another. The range could be virtually unlimited,
depending on the number of access points. Percon's Falcon
325 and Falcon
315 can be utilized in this
use local batch processing combined with an interactive link to a
central computer. These work primarily as interactive systems,
but they can function independently for a period of time if the
central computer fails. These systems are best used for
mission-critical applications where data collection is essential.
While most batch systems simply upload data
to a central computer, dual mode batch systems
can also download data from the computer to the batch system and
use it for data verification and other uses. These are not quite
so good as real-time interactive systems, but they are better
than straight batch systems.
Multiple interactive systems
connect more than one interactive system to a network. This way,
if one computer fails, another can still manage critical parts of
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modified: March 21, 2006