Sitting in one place for too long can hurt your productivity. That's the story behind increasingly versatile wireless communication systems for the plant and warehouse.

It wasn't so long ago that radio frequency data communication (RFDC) systems were used by a small portion of the workforce. Hand-held and vehicle-mounted RFDC terminals were the only options, and data transfer was slow, limiting the amount of data that could be exchanged in a reasonable time period. To top it off, terminals from different suppliers couldn't talk to each other.

All of those conditions have either already changed or are in the process of changing. Traditional RFDC terminals now share the same wireless network with personal digital assistants (PDAs), mobile computers, printers, voice systems, and even phones. Furthermore, these devices, which can talk to each other, exchange much larger quantities of information in less time than was previously possible. But perhaps most importantly, the trend is clearly to wider use of wireless systems by more people.

As the Gartner Group has put it, the question is not if mobile wireless technology will change your enterprise but when. Exploiting mobility must be a mandatory part of every enterprise's business and IT strategy, Gartner added in a recent report.

In a word, it's all about productivity. These mobile devices put key information in the hands of managers and workers when and where it will do them the most good. That's a tough value proposition to argue with in a tough economy. In addition, wireless systems allow materials handling operations to adapt more easily to dynamic supply chains that require higher throughput in less time without errors.

Handheld and vehicle-mounted terminals are being joined on a wireless local area network by a range of other devices including personal digital assistants, mobile computers, printers, voice systems, and phones.

Just ask Toyota Motor Manufacturing North America. The company's Kentucky operation will soon be using a single WLAN (Intermec, 425-348-2600, www.intermec.com) to support both office and plant floor operations. Out in the shop, the system will be managing the communication of all calls for replenishment parts, ensuring maximum productivity by keeping the lines supplied with enough parts at all times.

Toyota is not alone. Other familiar names from Alcoa and K-Mart to Compaq Computer and Sears are all using WLANs to improve productivity.

At their core, wireless systems are no different than before. They exchange information about inventory and orders with a host computer, saving the operator time and steps. The data transfer occurs over pre-set frequencies with a terminal or other device sending the information to antennas mounted in the facility. The receiving antenna then transfers the data over a wire to a base station controller linked to a host computer. After the warehouse management system (WMS) or other software processes the data, it sends back a message over the system to the terminal.

Other than those basics, most everything else has changed.

The watershed development was the first standard for radio frequency communications. That occurred in 1997 when the Institute of Electrical and Electronic Engineering (IEEE) released its 802.11 standard for interoperability of frequency hoping wireless devices. Frequency hoping allows the signal to shift to another frequency if it runs into interference during the transmission of data between two points, ensuring all of the information gets to its destination. Using a special network card, devices from different suppliers interoperate on a common communication backbone in the 2.4 GHz radio frequency band. Not only did the standard create interoperability, but it opened the door to much higher data rates.

A second standard, 802.11b, now covers direct sequence systems that send more data at higher speeds.

Data rates that started at 1mbps have escalated to 11 mbps now. Future high-speed systems that operate at 5 GHz are looking at data rates of 25 mbps plus under the latest standard – 802.11a.

Despite these new high-speed data capabilities, the user base of wireless systems has not yet changed dramatically, according to Greg Smith, vice president of wireless systems at Intermec. "Greater than 90% of the installed base is pre-802.11. However, about 60% of systems currently being installed comply with the standard," he says.

As it turns out, a new wireless communication standard is about to have an impact. With a much more colorful name than 802.11, Bluetooth has the same purpose - connect a wide range of wireless devices. But that doesn't put the two standards in competition with each other, explains Pam Corry, vice president of systems marketing at Intermec.

"Bluetooth is an excellent cable replacement technology," she says. "It does not have the range or throughput of 802.11. But it does a great job transmitting data at 1 Mbps from a hand-held terminal to a portable label printer, for instance, at distances up to 30 feet."

When it comes to devices for the plant and warehouse, Bluetooth is still in its early commercialization stages.

What are companies doing with all these new options? Quite a bit, actually.

To begin, they are taking advantage of the new device options, often to complement traditional hand-held and vehicle-mounted RFDC terminals.

Earlier this year, Sears announced plans to put in its 860 U.S. stores nearly 15,000 mobile handheld computers with WLAN capabilities (Symbol, 516-563-2400, www.symbol.com ). The mobile computers, which have a Palm OS operating system and a browser, will be used to perform critical functions such as receiving, replenishment, inventory management, and price changes. They will be tied to networked printers, creating a mobile printing environment.

Similarly, K-Mart plans to do much the same at its 2,100 stores. "This technology builds the infrastructure to enable every department company-wide to be linked and able to better satisfy our customers," says Michael Jones, divisional vice president, information technology and customer experience.

In England, retailer Somerfield, a supermarket chain, is using a WLAN in its Yorkshire warehouse. Twenty-five vehicle mounted terminals and six hand-helds (LXE, 770-447-4224, www.lxe.com) that comply with 802.11b are used to manage the flow of inventory in the 50,000 square meter facility.

Since the late '80s, data rates have increased from 10 kbps with UHF RFDC systems to 11 mbps today with 25 mbps plus emerging. The result is considerably more information can now pass over wireless networks in less time. Since high-end data rates are not needed for all applications, systems with lower requirements are still being installed.

Other well-known companies taking advantage of higher data rates and broader-based worker mobility include Compaq and Alcoa. Compaq now uses WLANs at multiple facilities. "By controlling inventory in real time and increasing labor efficiencies, we accelerate turnaround," says Grover Edmiston, director of operations for Compaq's refurbishment center. And at Alcoa, both vehicle-mounted and hand-held computers are used to increase productivity on its shop floor in Riverdale, Iowa.

Meanwhile, there are two voice-related applications for WLANs. One is voice-recognition. Workers wear a headset with microphone that allows them to collect data about receiving, picking, shipping, and other activities by speaking into the headset. This information is sent by WLAN to a central computer that records the data and sends back instructions that the worker hears through the headset. Such a system is used by P&O Cold Logistics in a freezer warehouse, allowing workers to keep their hands free for handling inventory under extreme conditions (see box).

The other voice-related option is a phone that is 802.11b compatible, sending data at 11mbps. This allows users to have voice communications with other people within the facility over a WLAN. At this point, these devices are just emerging with fewer than 60,000 such phones expected to be shipped this year.

Clearly, the world of wireless is changing with expanded capabilities and a broader array of devices leading the way into the future.