Going Wi-Fi: A Practical Guide to Planning and Building an 802.11 Network

Most of the networking hardware is common to every type of application, but there are exceptions. For example, specific vertical situations may require special antennae and/or client computing devices. In these situations, hardware selection may require a bit more thought before a final decision is made.

Not Your Every-Day Computing Devices

The typical wireless computing devices-laptops, PDAs, and tablet computers-oft-times aren't suitable for use in vertical industries. A large number of enterprise workers, including shop floor personnel, and warehouse and field service personnel, use mobile computing devices as they go about their daily tasks. The rough-and-tumble work environment and wide variety of applications that these workers face requires more rugged and diverse mobile computing and communications technology than the typical personal digital assistant (PDA) and laptop provides. Thus, ruggedized notebook computers, vehicle mount computers, pen tablet computers, handheld computers, and wearable computers are among the computing devices that may be used to access a vertical WLAN.

Many vertical industries, especially schools and hospitals, use wireless carts because of the hands-free mobility that they offer. All wireless carts come with a built-in wireless network card, but other than that, their features vary widely. For example, a wireless cart for use in an educational environment might be equipped with a number of laptop computers, a printer, an access point, a powerstrip, and Ethernet cable. Whereas a cart equipped for use in a healthcare facility might come with a flat-screen-monitor computer and a battery pack, so there is no need to look for an electrical outlet to use the cart's equipment. A specific situation may require mixing and matching components, for example combining a medical cart from EMS Technologies with a ruggedized computer from Amrel. Or carts like the ones Computerstation, Inc. offers, that provide a "clean room" environment, i.e. computer enclosure so the wireless computing device can be used confidently in a dusty, grimy, or damp work area.

Look for computing devices that can take the best advantage of a wireless network, but try to not limit the organization to a single vendor's device(s), even for a vertical application. Instead, select best of breed devices. Technology has advanced to the point where a well-designed wireless infrastructure can support any vendor's standard PCI bus radio boards and PCMCIA radio network interface cards. Also, you should be cognizant that it is possible to incorporate a variety of components into a wireless networking solution, for example, barcode scanners, time and attendance systems, scales, monitors and printers. Do your homework:

• Ask if the vendor offers a wide range of terminals and radios that will fill a variety of communications needs.

• Consider computing devices with proven technology. Be sure that the chosen device has been tested in a production environment, especially for mission-critical applications.

• If the organization is trying a new application, such as a voice-over-Wi-Fi system, keep your old system operational until you are certain the new application and its supporting devices work as expected.

• If the application requires barcode scanning, does the new system easily support such usage? If so, how?

• Does the device offer flexible data capture features? For example, is the handheld capable of operating as a "batch device," i.e. does it have ample memory to store large "look-up files" in secure, non-volatile memory for on-the-spot processing without the need for wirelessly accessing a server?

• Can the device decode the most popular barcode symbologies including, if needed, two dimensional (2D) symbologies such as PDF417 and microPDF?

• Can the handheld device support a variety of barcode scan engine options, including no-scan, standard, high-density, high-visibility, and long-range scans capable of reading bar codes to 15 feet (4.6 meters)?

• What type of data output does the device support? Text only, text and graphical, color, black and white, etc.

• Will the device's battery hold its charge for an entire day's shift, with some to spare? Test the device before buying. Some might hold a charge only when used moderately, but when used during, e.g., the annual inventory process, it might not hold up to the task.

• Is the device designed to perform in harsh environments and to withstand rough handling? Does it meet the IP65 standards for moisture and particle resistance?

Barcode Scanners

Barcode scanners read various types of barcode symbology, either through laser scanning or imaging technology. These devices scan and decode barcodes, helping to automate the data collection and transmission process, and thus improve productivity and reliability by limiting human intervention and reducing unreliable paperwork.

Organizations can choose between pure barcode readers, which are typically shaped like a gun (and include a trigger), or more multifaceted handhelds or PDAs with barcode reading capabilities. Scanners come in several design forms with varying degrees of functionality. For jobs that require a simple scan, an untethered barcode scanner is the appropriate choice. For situations that call for barcode scanning as well as data input, PDAs or handhelds with barcode reading capabilities may be more appropriate.

Symbol Technologies just recently began shipping a new ruggedized Pocket PC that sports support for voice-over-Wi-Fi as well as a built-in barcode scanner. The device, called the Symbol PDT 8146 Imaging Computer, is designed for mobile workers in industries such as transportation and logistics, public safety, and retail. According to Symbol, it is the first handheld to merge Wi-Fi voice over IP with imaging and data capture capabilities, enabling workers to speak to each other over 802.11b networks. VoWi-Fi is quickly becoming the hot IT item for the mobile worker segment.

Barcode Printing

Barcode printing products typically create 1D or 2D barcodes on label stock. These devices allow output from information technology systems, such as a WLAN to be displayed quickly and easily to better manage the supply chain. When considering the purchase of a barcode printing product, look for a device:

• That is fast and reliable, since barcodes often are rapidly applied to a large volume of items, such as on an assembly line.

• Durable enough to operate in tough environments, and flexible enough to print multiple printing formats, including text and graphics.

• Offers interoperability features. Although most printers operate on a proprietary software language, which has historically made implementation difficult and interoperability between different brands of printers impractical, there are vendor or third-party software solutions (i.e. middleware), which ease system implementation and allow for better interoperability.

• That can be managed from a central location so management can receive remote error notification from a malfunctioning printer, and that can diagnose and repair the error on a remote basis.

Portable Printers

Some vertical operations (e.g. retail, healthcare) require workers to tote around a handheld printer in addition to a portable computing device or barcode scanner. If this is the case, look for a device that is small and light enough to be used comfortably in a handheld operation, and that can print barcodes and text with high-quality print resolution. Another option to consider is a printer that can "cradle" its companion handheld device.