A personal digital assistant (PDA), also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet. A PDA has an electronic visual display, enabling it to include a web browser, but some newer models also have audio capabilities, enabling them to be used as mobile phones or portable media players. Many PDAs can access the Internet, intranets or extranets via Wi-Fi or Wireless Wide Area Networks. Many PDAs employ touchscreen technology.

The first PDA was released in 1986 by Psion, the Organizer II. Followed by Psion's Series 3, in 1991, which began to resemble the more familiar PDA style. It also had a full keyboard.

The term ''PDA'' was first used on January 7, 1992 by Apple Computer CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevada, referring to the Apple Newton. In 1996, Nokia introduced the first mobile phone with full PDA functionality, the 9000 Communicator, which grew to become the world's best-selling PDA. The Communicator spawned a new category of mobile phones: the "PDA phone", now called "smartphone". Another early entrant in this market was Palm, with a line of PDA products which began with the March 1996 Pilot 1000.

Today, almost all PDAs are smartphones. Over 150 million smartphones are sold each year, while "stand-alone" PDAs without phone functionality sell only about 3 million units per year.

Typical features

A typical PDA has a touchscreen for entering data, a memory card slot for data storage, and IrDA, Bluetooth and/or Wi-Fi. However, some PDAs may not have a touch screen, using softkeys, a directional pad, and a numeric keypad or a thumb keyboard for input; this is typically seen on telephones that are incidentally PDAs.

In order to have the functions expected of a PDA, a device's software typically includes an appointment calendar, a to-do list, an address book for contacts, a calculator, and some sort of memo (or "note") program. PDAs with wireless data connections also typically include an email client and a Web browser.

Touch screen

Many of the original PDAs, such as the Apple Newton and Palm Pilot, featured a touchscreen for user interaction, having only a few buttons—usually reserved for shortcuts to often-used programs. Touchscreen PDAs, including Windows Mobile devices, may have a detachable stylus to facilitate making selections. The user interacts with the device by tapping the screen to select buttons or issue commands, or by dragging a finger or the stylus on the screen to make selections or scroll.

Typical methods of entering text on touchscreen PDAs include:

A virtual keyboard, where a keyboard is shown on the touchscreen. Text is entered by tapping the on-screen keyboard with a finger or stylus.

An external keyboard connected via USB, Infrared port, or Bluetooth. Some users may choose a chorded keyboard for one-handed use.

Handwriting recognition, where letters or words are written on the touchscreen, and the PDA converts the input to text. Recognition and computation of handwritten horizontal and vertical formulas, such as "1 + 2 =", may also be a feature.

Stroke recognition allows the user to make a predefined set of strokes on the touchscreen, sometimes in a special input area, representing the various characters to be input. The strokes are often simplified character shapes, making them easier for the device to recognize. One widely-known stroke recognition system is Palm's Graffiti).

Despite rigorous research and development projects, end-users experience mixed results with handwriting recognition systems. Some find it frustrating and inaccurate, while others are satisfied with the quality of the recognition.

Touchscreen PDAs intended for business use, such as the BlackBerry and Palm Treo, usually also offer full keyboards and scroll wheels or thumbwheels to facilitate data entry and navigation.

Many touchscreen PDAs support some form of external keyboard as well. Specialized folding keyboards, which offer a full-sized keyboard but collapse into a compact size for transport, are available for many models. External keyboards may attach to the PDA directly, using a cable, or may use wireless technology such as infrared or Bluetooth to connect to the PDA.

Newer PDAs, such as the HTC HD2, Apple iPhone, Apple iPod Touch, and Palm Pre, Palm Pre Plus, Palm Pixi, Palm Pixi Plus, include more advanced forms of touchscreen that can register multiple touches simultaneously. These "multi-touch" displays allow for more sophisticated interfaces using various gestures entered with one or more fingers.

Memory cards

Although many early PDAs did not have memory card slots, now most have either some form of Secure Digital (SD) slot or a CompactFlash slot. Although originally designed for memory, Secure Digital Input/Output (SDIO) and CompactFlash cards are available that provide accessories like Wi-Fi or digital cameras, if the device can support them. Some PDAs also have a USB port, mainly for USB flash drives. Some PDAs use microSD cards, which are electronically compatible with SD cards, but have a much smaller physical size.

Wired connectivity

While early PDAs connected to a user's personal computer via serial ports or another proprietary connection, many today connect via a USB cable. PDAs are not typically able to connect to each other via USB, as USB requires one machine to act as a "host," which isn't a typical PDA function.

Some early PDAs were able to connect to the Internet indirectly by means off an external modem connected via the PDA's serial port or "sync" connector, or directly by using an expansion card that provided an Ethernet port.

Wireless connectivity

Most modern PDAs have Bluetooth a popular wireless protocol for mobile devices. Bluetooth can be used to connect keyboards, headsets, GPS receivers, and other nearby accessories. It's also possible to transfer files between PDAs that have Bluetooth.

Many modern PDAs have Wi-Fi wireless network connectivity, and can connect to Wi-Fi hotspots.

All smartphones, and some other modern PDAs like the Apple iPod touch, can connect to Wireless Wide Area Networks, such as those provided by cellular telecommunications companies.

Older PDAs from the 90s to 2006 typically had an IrDA (infrared) port allowing short-range, line-of-sight wireless communication. Few current models use this technology, as it has been supplanted by Bluetooth and Wi-Fi. IrDA allows communication between two PDAs, or between a PDA and any device with an IrDA port or adapter. Some printers have IrDA receivers, allowing IrDA-equipped PDAs to print to them, if the PDA's operating system supports it. Most universal PDA keyboards use infrared technology because many older PDAs have it. Infrared technology is low-cost and has the advantage of being allowed aboard aircraft.

Synchronization

Most PDAs can synchronize their data with applications on a user's personal computer. This allows the user to update contact, schedule, or other information on their computer, using software such as Microsoft Outlook or ACT!, and have that same data transferred to PDA—or transfer updated information from the PDA back to the computer. This eliminates the need for the user to update their data in two places.

Synchronization also prevents the loss of information stored on the device if it is lost, stolen, or destroyed. When the PDA is repaired or replaced, it can be "re-synced" with the computer, restoring the user's data.

Some users find that data input is quicker on their computer than on their PDA, since text input via a touchscreen or small-scale keyboard is slower than a full-size keyboard. Transferring data to a PDA via the computer is therefore a lot quicker than having to manually input all data on the handheld device.

Most PDAs come with the ability to synchronize to a computer. This is done through ''synchronization software'' provided with the handheld, or sometime with the computer's operating system. Examples of synchronization software include:

HotSync Manager, for Palm OS PDAs

Microsoft ActiveSync, used by Windows XP and older Windows operating systems to synchronize with Windows Mobile, Pocket PC, and Windows CE PDAs, as well as PDAs running iOS, Palm OS, and Symbian

Microsoft Windows Mobile Device Center for Windows Vista, which supports Microsoft Windows Mobile and Pocket PC devices.

Apple iTunes, used on Mac OS X and Microsoft Windows to sync iOS devices (such as the iPhone and iPod touch)

iSync, included with Mac OS X, can synchronize many SyncML-enabled PDAs

BlackBerry Desktop Software, used to sync BlackBerry devices

These programs allow the PDA to be synchronized with a personal information manager, which may be part of the computer's operating system, provided with the PDA, or sold separately by a third party. For example, the RIM BlackBerry comes with RIM's ''Desktop Manager'' program, which can synchronize to both Microsoft Outlook and ACT!.

Other PDAs come only with their own proprietary software. For example, some early Palm OS PDAs came only with Palm Desktop, while later Palm PDAs—such as the Treo 650—have the ability to sync to Palm Desktop or Microsoft Outlook. Microsoft's ActiveSync and Windows Mobile Device Center only synchronize with Microsoft Outlook or a Microsoft Exchange server.

Third-party synchronization software is also available for some PDAs from companies like CommonTime and CompanionLink. Third-party software can be used to synchronize PDAs to other personal information managers that are not supported by the PDA manufacturers (for example, GoldMine and IBM Lotus Notes).

Wireless synchronization

Some PDAs can synchronize some or all of their data using their wireless networking capabilities, rather than having to be directly connected to a personal computer via a cable.

Apple iOS devices, like the iPhone, iPod Touch, and iPad, can use Apple's MobileMe subscription service to synchronize calendar, address book, mail account, Internet bookmark, and other data with one or more Macintosh or Windows computers using Wi-Fi or cellular data connections.

Palm's webOS smartphones primarily sync with the cloud. For example, if Gmail is used, information in contacts, email, and calendar can be synchronized between the phone and Google's servers.

RIM sells BlackBerry Enterprise Server to corporations so that corporate BlackBerry users can wirelessly synchronize their PDAs with the company's Microsoft Exchange Server, IBM Lotus Domino, or Novell GroupWise servers. Email, calendar entries, contacts, tasks, and memos kept on the company's server are automatically synchronized with the BlackBerry.

Automobile navigation

Some PDAs include Global Positioning System (GPS) receivers; this is particularly true of smartphones. Other PDAs are compatible with external GPS-receiver add-ons that use the PDA's processor and screen to display location information.

PDAs with GPS functionality can be used for automotive navigation. PDAs are increasingly being fitted as standard on new cars.

PDA-based GPS can also display traffic conditions, perform dynamic routing, and show known locations of roadside mobile radar guns. TomTom, Garmin, and iGO offer GPS navigation software for PDAs.

Ruggedized PDAs

Some businesses and government organizations rely upon rugged PDAs, sometimes known as enterprise digital assistants (EDAs), for mobile data applications. EDAs often have extra features for data capture, such as barcode readers, radio-frequency identification (RFID) readers, magnetic stripe card readers, or smart card readers.

Typical applications include:

Military: Notably Army

supply chain management in warehouses

package delivery

route accounting

medical treatment and recordkeeping in hospitals

facilities maintenance and management

parking enforcement

access control and security

capital asset maintenance

meter reading by utilities

"wireless waitress" applications in restaurants and hospitality venues

Medical and scientific uses

Many companies have developed PDA products aimed at the medical professions' unique needs, such as drug databases, treatment information, and medical news. Services such as AvantGo translate medical journals into PDA-readable formats. WardWatch organizes medical records, providing reminders of information such as the treatment regimens of patients and programs to doctors making ward rounds. Pendragon and Syware provide tools for conducting research with PDAs, allowing the user to enter data into a centralized database using their PDA. Microsoft Visual Studio and Sun Java also provide programming tools for developing survey instruments on the handheld. These development tools allow for integration with SQL databases that are stored on the handheld and can be synchronized with a desktop- or server-based database.

PDAs have been shown to aid diagnosis and drug selection and some studies have concluded that when patients use PDAs to record their symptoms, they communicate more effectively with hospitals during follow-up visits.

The development of Sensor Web technology may lead to wearable bodily sensors to monitor ongoing conditions, like diabetes or epilepsy, which would alert patients and doctors when treatment is required using wireless communication and PDAs.

Educational uses

As mobile technology becomes more common, it is increasingly being used as a learning tool. Some educational institutions have embraced M-Learning, integrating PDAs into their teaching practices.

PDAs and handheld devices are allowed in many classrooms for digital note-taking. Students can spell-check, modify, and amend their class notes on the PDA. Some educators distribute course material through the Internet or infrared file-sharing functions of the PDA. Textbook publishers have begun to release e-books, or electronic textbooks, which can be uploaded directly to a PDA, reducing the number of textbooks students must carry.

Software companies have developed PDA programs to meet the instructional needs of educational institutions, such as dictionaries, thesauri, word processing software, encyclopedias, and digital lesson planners.

Recreational uses

PDAs may be used by music enthusiasts to play a variety of music file formats. Many PDAs include the functionality of an MP3 player.

Road rally enthusiasts can use PDAs to calculate distance, speed, and time. This information may be used for navigation, or the PDA's GPS functions can be used for navigation.

Underwater divers can use PDAs to plan breathing gas mixtures and decompression schedules using software such as "V-Planner."

PDAs for people with disabilities

PDAs offer varying degrees of accessibility for people with differing abilities, based on the particular device and service. People with vision, hearing, mobility, or speech impairments may be able to use PDAs on a limited basis. This use may be enhanced by accessibility software (e.g., speech recognition for verbal input instead of manual input). Universal design is relevant to PDAs as well as other technology, and a viable solution for many user-access issues, though it has yet to be consistently integrated into the design of popular consumer PDA devices.

PDAs are useful for people with traumatic brain injury or posttraumatic stress disorder, as seen in troops returning home from the Iraq War and Operation Enduring Freedom. PDAs help address memory problems, helping affected people with daily life organization and reminders. As of quite recently, the Department of Veterans' Affairs has issued thousands of PDAs to troops who need them. Occupational therapists have taken on a crucial role within this population helping these veterans return to the normality of life they once had.

Lists of PDAs

Popular consumer PDAs

Abacus PDA Watch

Acer N Series

AlphaSmart

Amida Simputer

BlackBerry

Encore Simputer

Fujitsu Siemens Computers Pocket LOOX

HP iPAQ

HTC Corporation (Dopod, Qtek)'s series of Windows Mobile PDA/phones (HTC)

HTC, especially the HTC P3470 (a.k.a. Pharos)

I-mate

Apple Inc. iPod touch, iPhone

Palm, Inc. smartphones under Palm OS and under the successor WebOS (Pre, and Pixi).

PocketMail (email PDA with built-in acoustic coupler)

Royal

Samsung Moment

Discontinued PDAs

Apple Newton

Atari Portfolio

Casio Pocket Viewer

Dell Axim

E-TEN

GMate Yopy

Handspring (company)

iPAQ

HP Jornada Pocket PC

LifeDrive

NEC MobilePro

Osaris running EPOC OS distributed by Oregon Scientific

Palm (PDA) (Tungsten E2, TX, Treo, Zire Handheld)

Philips Nino

Psion

Roland PMA-5 (Personal Music Assistant)

Sharp Wizard and Sharp Zaurus

Sony CLIÉ

Sony Magic Link with the Magic Cap operating system

Tapwave Zodiac

Toshiba e310

Rugged PDAs

ecom instruments

Getac

Motorola (Symbol Technologies)

Intermec

Psion Teklogix

Datalogic Mobile

Catchwell

Honeywell (Hand Held Products)

Pidion

Skeye (Hoeft & Wessel AG)

Trimble Navigation

Handheld Group

American industrial systems (Mil-Spec, IP67)

Unitech

See also

Automotive navigation system

Construction field computing

Danger Hiptop

Desknote

G1

Graffiti (Palm OS)

Hipster PDA

Information appliance

iOS (Apple)

Laptop

Medical calculator

Mobile software

MLearning

Mobile Web

Netbook

Palm OS

Personal area network

Personal communicator

Personal Information Display

Personal information management

Personal navigation assistant (PNA)

Screen protector

Smartphone

Subnotebook

Tablet PC

Ultra-Mobile PC

Wearable computer

Sena Cases

Timex Datalink

Virtual assistance

References

* Category:Mobile computers Category:Information appliances Category:Time management

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