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56-457: The ZYPAD is a PDA designed to be worn on a user's wrist like a bracer and offers interface port features similar to laptop computer. It was developed by Parvus, a military contractor, and Eurotech . It is arguable whether it qualifies as a watch, but it is referred to as a "Wrist Worn PC". It ships with Linux kernel 2.6 and also supports Windows CE 5.0, and can sense motion, allowing such possibilities of use such as going into standby mode when

112-419: A CompactFlash slot or a combination of the two. Although designed for memory, Secure Digital Input/Output (SDIO) and CompactFlash cards were made available that provided peripheral accessories like Wi-Fi or digital cameras to devices with software support. 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

168-672: A touchscreen for user interaction, having only a few buttons—usually reserved for shortcuts to often-used programs. Some touchscreen PDAs, including Windows Mobile devices, had 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: Despite research and development projects, end-users experienced mixed results with handwriting recognition systems. Some found it frustrating and inaccurate, while others were satisfied with

224-517: A PDA, reducing the number of textbooks students were required to carry. Brighton and SUSSEX Medical School in the UK was the first medical school to provide wide scale use of PDAs to its undergraduate students. The learning opportunities provided by having PDAs complete with a suite of key medical texts were studied with results showing that learning occurred in context with timely access to key facts and through consolidation of knowledge via repetition. The PDA

280-412: A biometric fingerprint scanner. Personal digital assistant A personal digital assistant ( PDA ) is a multi-purpose mobile device which functions as a personal information manager. Following a boom in the 1990s and 2000s, PDA's were mostly displaced by the widespread adoption of more highly capable smartphones , in particular those based on iOS and Android in the late 2000's, and thus saw

336-413: A few people. The invention of the telephone exchange provided the solution for establishing telephone connections with any other telephone in service in the local area. Each telephone was connected to the exchange at first with one wire, later one wire pair, the local loop . Nearby exchanges in other service areas were connected with trunk lines , and long-distance service could be established by relaying

392-474: A much smaller physical size. While early PDAs connected to a user's personal computer via serial ports and other proprietary connections , later models connect via a USB cable. Older PDAs were unable to connect to each other via USB , as their implementations of USB did not support acting as the "host". Some early PDAs were able to connect to the Internet indirectly by means of an external modem connected via

448-490: A rapid decline. A PDA has an electronic visual display . Most models also have audio capabilities, allowing usage as a portable media player , and also enabling many of them to be used as telephones. By the early 2000s, nearly all PDA models had the ability to access the Internet, intranets or extranets via Wi-Fi or Wireless WANs , and since then generally included a web browser . Sometimes, instead of buttons, later PDAs employ touchscreen technology. The first PDA,

504-473: A sense of community. In The Social Construction of Mobile Telephony it is suggested that each phone call and text message is more than an attempt to converse. Instead, it is a gesture which maintains the social network between family and friends. Although there is a loss of certain social cues through telephones, mobile phones bring new forms of expression of different cues that are understood by different audiences. New language additives attempt to compensate for

560-403: A telephone user wants to make a telephone call , equipment at the exchange examines the dialed telephone number and connects that telephone line to another in the same wire center, or to a trunk to a distant exchange. Most of the exchanges in the world are interconnected through a system of larger switching systems, forming the public switched telephone network (PSTN). In the second half of

616-473: A touchscreen or small-scale keyboard was slower than a full-size keyboard. Transferring data to a PDA via the computer was, 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 sometimes with the computer's operating system. Examples of synchronization software include: These programs allow

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672-530: A user lowers his/her arm. It can determine its position by dead reckoning as well as via GPS. It supports Bluetooth , IrDA , and WiFi . The ZYPAD debuted in 2006 and the ZYPAD WL 1000 was the first marketed device, followed by the WL 1100. Initial retail prices were set to be around $ 2000. The Zypad WR1100 debuted in 2008 and features housing made out of high strength fiberglass-reinforced nylon-magnesium alloy and

728-439: Is a major development in the evolution of office automation. The term is used in describing the computerized services of call centers, such as those that direct your phone call to the right department at a business you're calling. It is also sometimes used for the ability to use your personal computer to initiate and manage phone calls (in which case you can think of your computer as your personal call center). Digital telephony

784-456: Is also used on private networks which may or may not have a connection to the global telephone network. Direct person-to-person communication includes non-verbal cues expressed in facial and other bodily articulation, that cannot be transmitted in traditional voice telephony. Video telephony restores such interactions to varying degrees. Social Context Cues Theory is a model to measure the success of different types of communication in maintaining

840-566: Is relatively unregulated by government. In the United States, the Federal Communications Commission (FCC) regulates phone-to-phone connections, but says they do not plan to regulate connections between a phone user and an IP telephony service provider. A specialization of digital telephony, Internet Protocol (IP) telephony involves the application of digital networking technology that was the foundation to

896-455: Is the use of digital electronics in the operation and provisioning of telephony systems and services. Since the late 20th century, a digital core network has replaced the traditional analog transmission and signaling systems, and much of the access network has also been digitized. Starting with the development of transistor technology, originating from Bell Telephone Laboratories in 1947, to amplification and switching circuits in

952-507: Is well known, Wiesenfeld, Raghuram, and Garud point out that there is a value and efficiency to the type of communication for different tasks. They examine work places in which different types of communication, such as the telephone, are more useful than face-to-face interaction. The expansion of communication to mobile telephone service has created a different filter of the social cues than the land-line telephone. The use of instant messaging, such as texting , on mobile telephones has created

1008-515: The IBM Simon , which can also be considered the first smartphone. Then in 1996, Nokia introduced a PDA with digital cellphone functionality, the 9000 Communicator . Another early entrant in this market was Palm , with a line of PDA products which began in March 1996. Palm would eventually be the dominant vendor of PDAs until the rising popularity of Pocket PC devices in the early 2000s. By

1064-1175: The Internet to create, transmit, and receive telecommunications sessions over computer networks . Internet telephony is commonly known as voice over Internet Protocol (VoIP), reflecting the principle, but it has been referred with many other terms. VoIP has proven to be a disruptive technology that is rapidly replacing traditional telephone infrastructure technologies. As of January 2005, up to 10% of telephone subscribers in Japan and South Korea have switched to this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be "the next big thing". As of 2006, many VoIP companies offer service to consumers and businesses . IP telephony uses an Internet connection and hardware IP phones , analog telephone adapters, or softphone computer applications to transmit conversations encoded as data packets . In addition to replacing plain old telephone service (POTS), IP telephony services compete with mobile phone services by offering free or lower cost connections via WiFi hotspots . VoIP

1120-423: The Internet protocol suite . Since the advent of personal computer technology in the 1980s, computer telephony integration (CTI) has progressively provided more sophisticated telephony services, initiated and controlled by the computer, such as making and receiving voice, fax, and data calls with telephone directory services and caller identification . The integration of telephony software and computer systems

1176-689: The Organiser , was released in 1984 by Psion , followed by Psion's Series 3 , in 1991. The latter began to resemble the more familiar PDA style, including a full keyboard. The term PDA was first used on 7 January 1992 by Apple Inc. CEO John Sculley at the Consumer Electronics Show in Las Vegas , Nevada , referring to the Apple Newton . In 1994, IBM introduced the first PDA with analog cellular phone functionality,

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1232-443: The inside wiring permitted simple exchange of telephone sets with telephone plugs and allowed portability of the set to multiple locations in the premises where jacks were installed. The inside wiring to all jacks was connected in one place to the wire drop which connects the building to a cable. Cables usually bring a large number of drop wires from all over a district access network to one wire center or telephone exchange. When

1288-444: The last mile is digital, or where the conversion between digital and analog signals takes place inside the telephone. This advancement has reduced costs in communication, and improved the quality of voice services. The first implementation of this, ISDN , permitted all data transport from end-to-end speedily over telephone lines. This service was later made much less important due to the ability to provide digital services based on

1344-478: The modified discrete cosine transform (MDCT), has been widely adopted for speech coding in voice-over-IP (VoIP) applications since the late 1990s. The development of transmission methods such as SONET and fiber optic transmission further advanced digital transmission. Although analog carrier systems existed that multiplexed multiple analog voice channels onto a single transmission medium, digital transmission allowed lower cost and more channels multiplexed on

1400-410: The rapid scaling and miniaturization of MOS technology. Uncompressed PCM digital audio with 8-bit depth and 8   kHz sample rate requires a bit rate of 64   kbit/s , which was impractical for early digital telecommunication networks with limited network bandwidth . A solution to this issue was linear predictive coding (LPC), a speech coding data compression algorithm that

1456-497: The 1950s, the public switched telephone network (PSTN) has gradually moved towards solid-state electronics and automation . Following the development of computer -based electronic switching systems incorporating metal–oxide–semiconductor (MOS) and pulse-code modulation (PCM) technologies, the PSTN gradually evolved towards the digitization of signaling and audio transmissions . Digital telephony has since dramatically improved

1512-414: The 1990's to 2006, typically had an IrDA ( infrared ) port allowing short-range, line-of-sight wireless communication. Few later models used this technology, as it had 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 contemporary printers have IrDA receivers, allowing IrDA-equipped PDAs to print to them, if

1568-432: The 20th century, fax and data became important secondary applications of the network created to carry voices, and late in the century, parts of the network were upgraded with ISDN and DSL to improve handling of such traffic. Today, telephony uses digital technology ( digital telephony ) in the provisioning of telephone services and systems. Telephone calls can be provided digitally, but may be restricted to cases in which

1624-626: The MOS mixed-signal integrated circuit , which combines analog and digital signal processing on a single chip, developed by former Bell engineer David A. Hodges with Paul R. Gray at UC Berkeley in the early 1970s. In 1974, Hodges and Gray worked with R.E. Suarez to develop MOS switched capacitor (SC) circuit technology, which they used to develop a digital-to-analog converter (DAC) chip, using MOS capacitors and MOSFET switches for data conversion. MOS analog-to-digital converter (ADC) and DAC chips were commercialized by 1974. MOS SC circuits led to

1680-740: The PDA 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. The most common operating systems pre-installed on PDAs are: Other, rarely used operating systems: Some PDAs include Global Positioning System (GPS) receivers. Other PDAs are compatible with external GPS-receiver add-ons that use

1736-715: 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 , Palm Pre , Pre Plus , Pixi , and Pixi Plus , as well as devices running the Android operating system, 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. Although many early PDAs did not have memory card slots, later models had either some form of Secure Digital (SD) slot,

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1792-458: The PDA manufacturers (for example, GoldMine and IBM Lotus Notes ). 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. Devices running Palm's webOS or Google's Android operating system primarily sync with the cloud . For example, if Gmail is used, information in contacts, email, and calendars can be synchronized between

1848-528: 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 came 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

1904-432: The PDA's operating system supports it. Universal PDA keyboards designed for these older PDAs use infrared technology, due to cost and a lack of wireless interference. Most PDAs can synchronize their data with applications on a user's computer, allowing 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

1960-465: 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". Telephony Telephony is commonly referred to as the construction or operation of telephones and telephonic systems and as a system of telecommunications in which telephonic equipment is employed in the transmission of speech or other sound between points, with or without

2016-927: The PDA's processor and screen to display location information. PDAs with GPS functionality can be used for automotive navigation. Integrated PDA's were fitted as standard on new cars throughout the 2000's. PDA-based GPS can also display traffic conditions, perform dynamic routing, and show known locations of roadside mobile radar guns. TomTom , Garmin , and iGO offered GPS navigation software for PDAs. Some businesses and government organizations rely upon rugged PDAs, sometimes known as enterprise digital assistants (EDAs) or mobile computers , for mobile data applications. These PDAs have features that make them more robust and able to handle inclement weather, jolts, and moisture. 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. These features are designed to facilitate

2072-615: The PDA's serial port or "sync" connector, or directly by using an expansion card that provided an Ethernet port. Most PDAs use Bluetooth, a popular wireless protocol for mobile devices. Bluetooth can be used to connect keyboards, headsets, GPS receivers , and other nearby accessories. It is also possible to transfer files between PDAs that have Bluetooth. Many PDAs have Wi-Fi wireless network connectivity and can connect to Wi-Fi hotspots. All smartphones, and some other PDAs, can connect to Wireless Wide Area Networks, such as those provided by cellular telecommunications companies. Older PDAs, from

2128-513: The PDA—or transfer updated information from the PDA back to the computer, eliminating 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 found that data input was quicker on their computer than on their PDA since text input via

2184-499: The Treo 650—have the ability to sync to Palm Desktop or Microsoft Outlook. Microsoft's ActiveSync and Windows Mobile Device Center only synchronized with Microsoft Outlook or a Microsoft Exchange server. Third-party synchronization software was 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

2240-416: The advent of new communication technologies. Telephony now includes the technologies of Internet services and mobile communication, including video conferencing. The new technologies based on Internet Protocol (IP) concepts are often referred to separately as voice over IP (VoIP) telephony, also commonly referred to as IP telephony or Internet telephony. Unlike traditional phone service, IP telephony service

2296-399: The bandwidth-limited analog voice signal and encoding using pulse-code modulation (PCM). Early PCM codec - filters were implemented as passive resistor – capacitor – inductor filter circuits, with analog-to-digital conversion (for digitizing voices) and digital-to-analog conversion (for reconstructing voices) handled by discrete devices . Early digital telephony was impractical due to

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2352-440: The calls through multiple exchanges. Initially, exchange switchboards were manually operated by an attendant, commonly referred to as the " switchboard operator ". When a customer cranked a handle on the telephone, it activated an indicator on the board in front of the operator, who would in response plug the operator headset into that jack and offer service. The caller had to ask for the called party by name, later by number, and

2408-420: The capacity, quality and cost of the network. Digitization allows wideband voice on the same channel, with improved quality of a wider analog voice channel. The earliest end-to-end analog telephone networks to be modified and upgraded to transmission networks with Digital Signal 1 (DS1/T1) carrier systems date back to the early 1960s. They were designed to support the basic 3 kHz voice channel by sampling

2464-1115: The development of PCM codec-filter chips in the late 1970s. The silicon-gate CMOS (complementary MOS) PCM codec-filter chip, developed by Hodges and W.C. Black in 1980, has since been the industry standard for digital telephony. By the 1990s, telecommunication networks such as the public switched telephone network (PSTN) had been largely digitized with very-large-scale integration (VLSI) CMOS PCM codec-filters, widely used in electronic switching systems for telephone exchanges , private branch exchanges (PBX) and key telephone systems (KTS); user-end modems ; data transmission applications such as digital loop carriers , pair gain multiplexers , telephone loop extenders , integrated services digital network (ISDN) terminals, digital cordless telephones and digital cell phones ; and applications such as speech recognition equipment, voice data storage , voice mail and digital tapeless answering machines . The bandwidth of digital telecommunication networks has been rapidly increasing at an exponential rate, as observed by Edholm's law , largely driven by

2520-455: The first transistors in which drain and source were adjacent at the surface. Subsequently, a team demonstrated a working MOSFET at Bell Labs 1960. MOS technology was initially overlooked by Bell because they did not find it practical for analog telephone applications, before it was commercialized by Fairchild and RCA for digital electronics such as computers . MOS technology eventually became practical for telephone applications with

2576-440: 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, and may or may not include telephony functionality. Many of the original PDAs, such as the Apple Newton and Palm Pilot , featured

2632-400: The low performance and high costs of early PCM codec-filters. Practical digital telecommunication was enabled by the invention of the metal–oxide–semiconductor field-effect transistor (MOSFET), which led to the rapid development and wide adoption of PCM digital telephony. In 1957, Frosch and Derick were able to manufacture the first silicon dioxide field effect transistors at Bell Labs,

2688-405: The mid-2000s most PDAs had morphed into smartphones as classic PDAs without cellular radios were increasingly becoming uncommon. A typical PDA has a touchscreen for navigation, a memory card slot for data storage, and IrDA , Bluetooth and/or Wi-Fi . However, some PDAs may not have a touchscreen , using soft keys , a directional pad, and a numeric keypad or a thumb keyboard for input. To have

2744-433: The non-verbal cues present in face-to-face interactions. The research examines many different cues, such as the physical context, different facial expressions, body movements, tone of voice, touch and smell. Various communication cues are lost with the usage of the telephone. The communicating parties are not able to identify the body movements, and lack touch and smell. Although this diminished ability to identify social cues

2800-472: The operator connected one end of a circuit into the called party jack to alert them. If the called station answered, the operator disconnected their headset and completed the station-to-station circuit. Trunk calls were made with the assistance of other operators at other exchangers in the network. Until the 1970s, most telephones were permanently wired to the telephone line installed at customer premises. Later, conversion to installation of jacks that terminated

2856-541: 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, were made available for many models. External keyboards may attach to

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2912-465: The transmission medium. Today the end instrument often remains analog but the analog signals are typically converted to digital signals at the serving area interface (SAI), central office (CO), or other aggregation point. Digital loop carriers (DLC) and fiber to the x place the digital network ever closer to the customer premises, relegating the analog local loop to legacy status. The field of technology available for telephony has broadened with

2968-432: The use of these devices to scan product or item codes. Typical applications include: PDAs and handheld devices were allowed in many classrooms for digital note-taking. Students could spell-check, modify, and amend their class notes on a PDA. Some educators distributed course material through the Internet or infrared file-sharing functions of the PDA. Textbook publishers released e-books , which can be uploaded directly to

3024-552: The use of wires. The term is also used frequently to refer to computer hardware , software , and computer network systems, that perform functions traditionally performed by telephone equipment. In this context the technology is specifically referred to as Internet telephony, or voice over Internet Protocol (VoIP). The first telephones were connected directly in pairs. Each user had a separate telephone wired to each locations to be reached. This quickly became inconvenient and unmanageable when users wanted to communicate with more than

3080-559: Was an important addition to the learning ecology rather than a replacement. Software companies also developed PDA programs to meet the instructional needs of educational institutions, such as dictionaries, thesauri , word processing software, encyclopedias, webinars and digital lesson planners. PDAs were 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

3136-451: Was first proposed by Fumitada Itakura of Nagoya University and Shuzo Saito of Nippon Telegraph and Telephone (NTT) in 1966. LPC was capable of audio data compression down to 2.4   kbit/s, leading to the first successful real-time conversations over digital networks in the 1970s. LPC has since been the most widely used speech coding method. Another audio data compression method, a discrete cosine transform (DCT) algorithm called

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