Inventory Management and Warehouse Operations.


Automated Data Collection (ADC) Basics

By Dave Piasecki

Automated Data Collection (ADC), also known as Automated Data Capture (ADC), Automated Identification (AutoID), Automated Identification and Data Capture (AIDC), and by many as just "Barcoding" consists of many technologies including some that have nothing to do with bar codes.  Voice systems, RFID, OCR, pick-to-light, laser scanners, CCD scanners,  hand-held batch and RF terminals,  vehicle-mounted computers,  and wearable computers are all part of the ADC picture.

The fear of six-figure project costs often prevent many small to mid-sized manufacturers and distributors from taking advantage of Automated Data Collection (ADC) technologies. The key to implementing cost-effective ADC systems is knowing what technologies are available and the amount of integration required to implement them. Applying this knowledge to the processes in your operation will help you in developing the scope of your project. Limiting your project to or prioritizing by those applications that have a high benefit/cost ratio will allow you to apply these operational improvement technologies within a reasonable budget.  For example, adding a keyboard-wedge bar-code scanner to an existing PC or terminal in a production or warehouse area is a very low cost method for applying ADC to existing shop-floor reporting and shipping applications. This type of hardware is inexpensive and the only real programming required is that needed to add a bar code to the form (work order, pick slip, etc.)

Bar codes

Bar codeThere are two major categories of bar codes, one dimensional (1D), and two dimensional (2D).  1D barcodes are the ones we are most familiar with and consist of many different symbologies including UPC, Code 128, Code 39, Interleaved 2 of 5, just to name a few (there may also be variations within a specific symbology). The symbology you use may be dictated by supply chain partners through a standardized compliance label program or, if only used internally, can be chosen based upon specific application (tip:  if looking for a flexible symbology to use internally on documents, labels, license plates, etc. you will find Code 128 a good choice).  2D Bar Code2D bar code symbologies such as UPS's MaxiCode (shown right), are capable of storing more data then their 1D counterparts and require special scanners to read them. Although I would expect to see continued growth in the use of 2D bar codes, most warehouse and shop floor applications will continue to use 1D symbologies simply because you generally only need enough data in the bar code to access the associated records in your inventory system database, plus you can more easily scan 1D bar codes from a distance. . If you're interested in more detailed information and specs on bar codes I recommend getting a copy of The Bar Code Book by Roger C. Palmer.

Bar-code scanners

Laser or CCD. 

There are primarily two technologies used to read bar codes. Laser scanners use a laser beam that moves back and forth across the bar code reading the light and dark spaces.  Laser scanners have been in use for decades and are capable of scanning bar codes at significant distances.  CCD (charged coupled device) scanners act like a small digital camera and take a digital image of the bar code which is then decoded.  CCD scanners offer a lower cost but may be limited to a shorter scan distance.   Because of the scan distance limitations, users in a warehouse environment will likely find laser scanners to be their best choice when scanning from a forklift, however, for applications were bar codes are read from documents — such as in a shop-floor production-reporting application — CCD scanners should work fine.


Autodiscrimination describes the  functionality of a bar code reader to recognize the bar code symbology being scanned thus allowing a reader to read several different symbologies consecutively.  Most scanners come with this functionality and also allow you to program them to read only certain symbologies (this prevents someone from scanning the wrong bar code when multiple bar codes are present).

Bar Code ScannerTypical separate scanners used as input devices. 

A basic bar code scanner will plug into a Computer via USB or use some form of wireless technology. This is just used as an input device to the computer (we used to call this a keyboard-wedge interface). More simply put, the computer program doesn't know that a scanner is attached and treats the data as though it were key strokes from the user.  The advantage of this is that there is no need for special software or programming on the computer. In its simplest application you hook the scanner up, make sure the curser is in the correct field, scan a bar code containing the data you need such as a work order number, an item number, or a location, and the data will immediately appear in the field on the screen. 

Although this type of application can prove to be very useful and essentially works right "out of the box", you will find that by taking advantage of the programmable features of some devices you can take this functionality much further.  This is where it gets a little confusing as the programming and functionality is a little different based upon the hardware and software you purchase.  Some scanners have built in programming functionality, and there is also PC software that can perform tasks related to the data input from a scanner.  The good news is that you don't need to be a programmer to use this functionality.  If you have ever worked with macros you'll easily understand this type of programming.  What most of these programs allow you to do is to parse data from a bar code (allowing you to put several pieces of data in the same bar code such as item number and quantity, or customer number and shipping method) and also add keystrokes not included in the bar code such as tabs to move between fields, default data, function keys or enter keystrokes to complete transactions.

These types of scanners offer a low cost entry into the world of automated data collection and can provide increases in accuracy and productivity in many data entry applications. If you just want to start fiddling around with scanning barcodes to get a feel for how the technology works, you can get some really cheap bar-code scanners online. Keep in mind that a $20 scanner you find online is unlikely to be as good as a more expensive one from a name brand, but they can be useful for some simple low volume tasks.

Fixed Position Scanners. 

Fixed position scanners are used where a bar code is moved in front of the scanner as opposed to the scanner being moved to the bar code.  Applications include grocery check out counters and automated conveyor systems.  Many fixed position scanners are omni-directional which means that the bar code does not have to be oriented any specific way to be read.

Go to's Bar Code Scanner Links.

Portable computers 

Portable computers come in a vast variety of designs with varying levels of functionality. 

Batch versus RF. 

Batch terminals are used to collect data into files on the device and are later connected to a computer to have the files downloaded.  RF terminals use radio frequency waves to communicate live with the host system or network.  While batch devices were heavily used in the past and still have viable applications today, the introduction of  wireless standards has made RF technology much more affordable and easier to maintain and implement.

Portable Hand Held Bar Code Code ScannerHand-held devices.

I have a few problems with the basic nature of hand-held devices themselves.  First of all, "hand held" implies that you will be using one hand to hold the device.  Well, in most warehousing and material-handling environments this is a problem since that hand can no longer be used  to handle materials or operate controls of material-handling equipment. In addition, hand-held terminals generally have very small displays that are sometimes difficult to read as well as very small, confusing keypads that are difficult to enter data into.  This doesn't mean that these can't be valuable tools in your operation, only that you need to be sure to consider all the factors when implementing this type of technology.  Hand-held devices typically come with integrated bar-code scanners (as shown).

Hand-held Tips:

  • The old standard hand-held device design (like that shown) have little use in a warehouse outside of maybe a cycle count program.  Instead, use the pistol-grip models which allow your workers to more quickly holster the device between scans to make use of both their hands. There are also some newer more ergonomic hand-held devices that provide similar functionality to a pistol grip, but in a different form factor.
  • Keep the prompts as simple as possible.  The prompts should show only the bare minimum amount of data necessary to perform the task.
  • Minimize or eliminate data entry on keypads or touch screens.  As I said before, the keypads on these devices are difficult to use especially with alpha characters.  Limit data entry to numeric data as much as possible and also eliminate the need to have to enter tabs or enter keys.

Phones used as portable bar code computers?

From a computing standpoint, our cell phones today have far more computing capabilities than you need for these types of tasks. The build-in cameras are capable of scanning bar codes, and there are also some free or very cheap apps available that will give you some inventory tracking capabilities. So why not just use your phone? Well, I'm not saying you can't, but there are some things to consider. In my experience, scanning bar codes with the phone camera is not as fast as using a purpose-built laser or ccd scanner, and doesn't scan well from distances. Plus, the form-factor of the phone isn't neccessarily the best for warehouse work. There are some purpose-build bar code scanners that can be attached to some models of phones, or you can use a wireless scanner as an input device to overcome the camera-scanning issues. And there are even some "purpose-built" portable devices that are essentially a phone with some modifications. This is an area that continues to change, so while I still think operations with high transactional volume would be better off with purpose-built devices, a cell phone is a potential option in other operations.


Vehicle-mounted devices. 

Vehicle-mounted devices have several advantages over hand held devices including larger screens (even up to full sized screens), larger keypads similar to a standard keyboard on a portable computer, and you can't drop, loose, or forget to charge them. .  When using a full-screen vehicle-mounted device, integration can be much simpler as you can use your existing programs designed for desktop computers (although you should still consider simplifying the screens). Obviously you need to be performing tasks using some type of a vehicle (lift truck, tug, cart, etc) to use a vehicle-mount device.  Generally, vehicle-mounted devices use a separate wired or wireless bar-code scanner to input data.  Tips for using vehicle-mounted devices are similar to those for hand-helds (simple prompts, minimize data entry) but you should also consult with your vehicle manufacturer for recommendations on where to mount the device to ensure safe operation of the vehicle.

Wearable Systems. 

Wearable systems will likely have the most growth in coming years.  Currently offerings in wearable systems are limited and include devices like Symbol's WS series (nicknamed the Gladiator) that is strapped to the wrist/forearm and uses a small ring-type laser scanner for reading bar codes, or the Talkman from Vocollect which is designed for voice systems (more on voice systems below).  Wearable systems provide the functionality of hand-held devices while still allowing workers to use both hands.  I should caution you that several hand-held manufacturers have taken their hand-held devices, put them in a fanny pack, connected them to a voice headset or ring scanner and call them a "wearable system".  While technically this is a wearable system, I personally would not want to carry around the added bulk and weight of a device designed with an LCD display and keypad for 8 hours a day just because the manufacturer didn't want to make the effort to design a wearable-specific device.

Go to's Portable Computer Links

Voice Technology

Voice TechnologyVoice technology (a.k.a. Speech-based systems) has come of age in recent years and is now a very viable and desirable solution in warehouse and shop floor data collection applications.  Voice technology is really composed of two technologies. Voice Directed, which converts computer data into audible commands, and Speech Recognition, which allows user voice input to be converted into data.  Portable voice systems consist of a headset with a microphone and a wearable computer. 

The advantages of voice systems are hands-free and eyes-free operation that allows people to communicate with a computer the way people communicate with each other. Applications for voice systems include order picking, quality inspection, shipping, receiving, cycle counting.

Speech recognition capabilities have been gradually improving through better software and hardware, however, this is not yet a perfected technology.  To compensate for problems associated with speech recognition, you really need to limit the speech input to a fairly short list of keywords and phrases for commands, and primarily numeric characters for voice data input.  Alpha characters would have to be spoken phonetically ( Alpha, Bravo,Charlie, . . . Zulu) to maintain an acceptable level of accuracy.  Fortunately, many warehouse and shop floor tasks can be performed very effectively within these limitations.

Go to's Voice Technology Links


RFID TagRFID, Radio Frequency Identification.  Refers to devices attached to an object that transmit data to an RFID receiver.  These devices can be large pieces of hardware the size of a small book like those attached to ocean containers, or very small devices inserted into a label on a package.  RFID has advantages over bar codes such as the ability to hold more data, the ability to change the stored data as processing occurs, does not require line-of-site to transfer data, and is very effective in harsh environments where bar code labels won't work. RFID is not without it's own problems , RF signals can be compromised by materials such as metals and liquids. 

A little RFID vocabulary:

Active tags
are RFID tags that contain their own power source (battery) and have longer read ranges.
Passive tags
are powered by the signal generated from the reader device.
Read/write tags
can have their data changed.
Read only tags
are programmed once and their data cannot be changed.
EPC (electronic product code)
is a set of standards designed to utilize RFID technology for the tracking of individual items as well as cases and pallets. EPC is similar to UPC used for bar code tracking of consumer goods.
GTAG (global tag)
is an international RFID standard that can be used for general asset tracking.
RFID Reader,
also known as an interrogator, is a device that reads RFID tags.

Although RFID technology is getting a lot of attention these days it still tends to be cost prohibitive for most inventory tracking applications.  As chip prices go down you will continue to see growth in the application of RFID, however, as in the case of 2D bar codes, many warehouse and shop floor application simply don't require this added functionality. The low cost 1D bar code will likely continue to be the technology of choice for many inventory tracking applications. More info on RFID is available at my RFID Updates page.

Go to's RFID Links

Optical character recognition (OCR)

For years OCR has been used in mail sorting and document management, but has had very little application in warehouse and manufacturing operations primarily because it is not as accurate as bar code technology.  While I don't necessarily see OCR entering the warehouse in the near future, I'm not ready to write off the technology.  As hardware and software improves we may see this "old" technology make a comeback.  The primary advantage of OCR is that it can read the same characters that a human can read, eliminating the need for both a bar code and human readable text on labels, documents, etc. It also provides the ability to input data from documents  that do not include bar coded information.

Light systems

Pick to Light

Although some may argue whether or not a pick-to-light system is an ADC technology, the fact is they accomplish some of the same tasks.  Pick-to-light systems consist of lights and LED displays for each pick location.  The system uses software to light the next pick and display the quantity to pick.  Pick-to-light systems have the advantage of not only increasing accuracy, but also increasing productivity.  Since hardware is required for each pick location, pick-to-light systems are easier to cost justify where very high picks per SKU occur.  Carton flow rack and horizontal carousels are good applications for pick to light.  In batch picking, pick to light is also incorporated into the cart or rack that holds the cartons or totes that you are picking into (put-to-light).   See article on Order Picking .

Integration of ADC Technology

While hardware costs of ADC equipment continue to come down, the cost of integration will often prove to be the project buster.  Software and Integration costs will often be several times the cost of the hardware, especially in smaller operations where only a few devices will be used. 

Integration of ADC technologies is also far from standardized.  For example, when implementing an F system with portable terminals, one integrator may create a program on the terminals that will write directly to the file on the host system, another may create programs on a separate server to do this, another may write or modify a program on your host system and use terminal emulation software, and another may use a screen mapping tool to reformat an existing program to be used on the portable device.  Make sure you do your homework and talk to several integrators to ensure you are getting the best solution.  Also make sure you participate heavily in equipment selection and program/process design (prompts, data input) to ensure you get a system that provides the highest levels of accuracy and productivity.

There are also integration tools available that allow non-programmers (you will need some pretty good computer skills though) to integrate these technologies with host systems.  These tools will not have the functionality and flexibility of a good custom written program but may be adequate for simple applications.

Warehouse Management Systems (WMS) often come with interfaces to specific ADC equipment.  If your looking to add ADC to your warehouse you may want to first look at a WMS (read my article on WMS).

One of the biggest mistakes made when developing an ADC project is that people approach ADC as an "all or nothing" project.  The end result being that the when the project is quoted it tends to come in too costly to ever get implemented.  There is rarely significant financial benefit to using the "big bang" approach to ADC projects, so start small with the processes that can best benefit from the application of ADC and add on other processes later.

Mixing ADC Technologies, AKA Multimodal Data Collection.

Mixing ADC technologies is becoming more common. See my article on Multimodal Data Collection.

Related terminology from the Dictionary Glossary

ADC, Automated Data Collection 
aka AIDC, Automatic Identification & Data Collection. Systems of hardware and software used to process transactions in warehouses and manufacturing operations.  Data collection systems may consist of fixed terminals, portable terminals and computers, Radio frequency (RF) terminals, and various types of bar code scanners.
ASN, Advanced Shipment Notification. 
Advanced shipment notifications are used to notify a customer of a shipment.  ASNs will often include PO numbers, SKU numbers, lot numbers, quantity, pallet or container number, carton number.  ASNs may be paper-based, however, electronic notification is preferred.  Advanced shipment notification systems are usually combined with bar-coded compliance labeling which allows the customer to receive the shipment into inventory through the use of bar code scanners and automated data collection systems.
The functionality of a bar-code reader to recognize the bar code symbology being scanned thus allowing a reader to read several different symbologies consecutively.
Charged Coupled Device. Used to describe a type of barcode scanner that acts like a small digital camera that takes a digital image of the barcode as opposed to the standard barcode scanner that uses a laser.  CCD scanners are a low cost option for scanning barcodes at a short distance (usually within a few inches).
Compliance labels. 
Standardized label formats used by trading partners usually containing bar codes. Compliance labels are used as shipping labels, container/pallet labels, carton labels, piece labels.  Many bar code labeling software products now have the more common compliance label standards set up as templates.
Program generator
a.k.a. code generator, development tools .  Program generators are software programs that generally provide graphical user interfaces and tools that allow a user to create a program without having to write actual computer code. Currently, these programs are more frequently referred to as "development tools" and are usually designed to write code for specific applications such as data collection programs for portable computers.  While a user does not need to be a programmer to use this software, the user does need to have a higher level of technical skills than that of most standard software users.
Radio frequency (RF). 
In warehousing refers to the portable data collection devices that use radio frequency to transmit data to host system.
RFID, Radio frequency identification. 
Refers to devices attached to an object that transmit data to an RFID receiver.  These devices can be large pieces of hardware the size of a small book like those attached to ocean containers or very small devices inserted into a label on a package.  RFID has advantages over Bar codes such as the ability to hold more data, the ability to change the stored data as processing occurs, does not require line-of-site to transfer data and is very effective in harsh environments where bar code labels won't work.
RTLS, Real-time locator system. 
A real-time locator system uses RFID technology that provides the objects they are attached to the ability to transmit their current location.  System requires some type of RFID tag to be attached to each object that needs to be tracked, and RF transmitters/receivers located throughout the facility to determine the location and send information to computerized tracking system. While it sounds like a great way to eliminate "lost" inventory, the systems are still too costly for most inventory tracking operations and are more likely to be used to track more valuable assets.
Screen mapping.
a.k.a. Screen scraping  Software that provides the functionality to change the arrangement of data fields on a computer screen that accesses a mainframe computer program.  Screen mapping is frequently used in combination with terminal-emulation software to "remap" data fields from a standard mainframe program to be used on the smaller screen of a portable hand-held device.
Speech-based technology. 
Speech-based technology, also known as voice technology is really composed of two technologies:  Voice directed, which converts computer data into audible commands, and speech recognition, which allows user voice input to be converted into data.  Portable voice systems consist of a headset with a microphone and a wearable computer.
Terminal emulation. 
Software used on desktop and portable computers that allows the computer to act like a terminal connected to a mainframe system. If you have a networked desktop PC and are accessing mainframe programs ( a.k.a. green screen programs) you are using terminal emulation.  Terminal emulation is also a common method used to connect portable computers (as in warehouse bar code data collection systems) to mainframe software.
WMS, Warehouse Management System. 
Computer software designed specifically for managing the movement and storage of materials throughout the warehouse.  WMS functionality is generally broken down into the following three operations:  putaway, replenishment, and picking.  The key to these systems is the logic to direct these operations to specific locations base on user defined criteria.  WMSs are often set up to integrate with data collection systems.  Read my article on Warehouse Management Systems.

Links to ADC equipment manufacturers

Also read my article on Multi-modal Data Collection.

Go to Articles Page for more articles by Dave Piasecki.

Dave Piasecki, is owner/operator of Inventory Operations Consulting LLC, a consulting firm providing services related to inventory management, material handling, and warehouse operations. He has over 25 years experience in operations management and can be reached through his website (, where he maintains additional relevant information.

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