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Chameleon Warehouse Management Systems
Chameleon Warehouse Management Systems

 Overview of Voice-Directed Warehousing


The first incarnations of voice directed warehousing were implemented in distribution operations in the early 90s. Since then, Voice has changed dramatically. Most notably, the technology was originally limited to picking, whereas now all warehouse functions (picking, receiving/put-away, replenishment, shipping) can be coordinated by voice systems. These other functions are only now coming into their own, and despite considerable accuracy and efficiency gains that can be made in these areas, most companies still justify voice implementation on picking gains alone.


Primary benefits of implementing voice systems in the warehouse include:
- Increased picking accuracy
- Increased inventory accuracy
- Increased employee productivity
- Reduced new worker training time
- Increases job satisfaction for warehouse associates

How it works

Each operator is given a voice-enabled RF device. These devices need not have screens or keypads – operators communicate with the system via headset.

Managers use the WMS or middleware (more on this later) to assign operators work – jobs such as picking, put-away, replenishment, and shipping. How this assignment process takes place is largely implementation specific. For example, operators might be assigned to pick specific orders or load specific trucks - or they might simply be assigned to picking, and be automatically placed on the highest-priority job.


With voice picking, the voice system directs the operator to perform each pick, giving them directions to the pick location. Depending on system configuration, the operator may be prompted for a location check-digit or a container check-digit as well as a count-back. Following is an example picking dialog:

Computer: Go to building one.
Operator: Ready
Computer: Aisle five
Operator: Ready
Computer: Bay twenty-seven
Operator: Ready
Computer: Pick four cases of double-chocolate almond fudge
Operator: Ready
Computer: What are the check-digits?
Operator: Four-Five-Three (these might be from the pallet license or location)
Computer: How much remains? (Optional count-back – increase accuracy and reduce speed)
Operator: Seven
Computer: Go to aisle six…

…and so on, until the order is complete. The system then directs them to the location to put their pallet (onto a truck, into a staging area) and then tells them to take a new pallet and start the next pick. Unique license plates can be assigned to each picked pallet so that they can be easily located in the warehouse – and so that the voice system can direct the process of loading staged pallets onto trucks.


In voice directed put-away, the system asks the operator for the license(s) that they will be putting away. The system then directs the operator to put away each license, requesting a location check-digit from the put-away location.

Some systems can also take advantage of quicker multi-pallet walkies by performing two-phase putaway. Walkie operators are directed to take received pallets to the appropriate aisle where reach operators pick them up and complete the operation.


In voice directed replenishment, the system directs the operator to pick up a particular skid from a particular location, and then directs them to the appropriate picking location.

The WMS coordinates which pallets are scheduled for replenishment, and where they are to be put – a sophisticated WMS may assign SKUs to pickfaces dynamically according to SKU velocity, available space, proximity to door, etc.

Truck Loading

With voice directed truck loading, the voice system directs the operator to each picked skid in the proper sequence. In full-pallet DCs, operators may be directed to take entire pallets from the racking directly to the truck. Voice-directed truck-loading can help ensure that trucks are loaded in the correct sequence and that all pallets make it onto the truck.

Voice Training

Apart from training users to use the voice system, the system must be trained to understand each user. This training process takes roughly 30-45 minutes - during this time, the user is asked to repeat aloud the words they will be using when they communicate with the system. The voice system learns how the particular operator speaks, and saves a template of their speech patterns. This allows voice systems to understand users with heavy accents – the system knows how each individual user pronounces each word.


With the additional security provided by voice, it is easier to enforce particular rules. For example, you could (if your WMS supports it) create job templates for each user. This means that you could, specify which users were qualified to use a reach truck – and prevent others from receiving these assignments.

WMS or Middleware

Being a relatively new technology, only a few WMS systems are specifically designed to support voice direction. Middleware is often required to act as an agent between the WMS and the voice system – and to provide additional functionality such as job assignments, productivity monitoring, etc. that most WMS systems cannot provide out of the box.

Other Resources:

Video Demonstrations

Check out these videos for examples of voice-directed picking in action.

· read more

Voice-Directed Warehousing FAQ

Frequently asked questions about voice-directed warehousing systems.

· read more

Voice Picking ROI Calculator

Calculate your estimated ROI from implementing a voice system.

· read more



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