PDA (Personal Digital Assistant), also known as handheld computer, can help us to work, study, and play on the move.Classified by use, divided intoIndustrial PDAAnd consumer goods PDAs.Industrial PDA is mainly used in the industrial field, and the common ones areBar code scanner、RFID reader writer、POS machineCan be called PDA;There are many consumer goods PDAs,Intelligent mobile phone、tablet PC, hand-held game console, etc.
PDAPersonal Digital Assistant means personal digital assistant.As its name implies, it is a digital tool to assist personal work, mainly providing notesmail list, business card exchange, itinerary and other functions.
With the explosive development of science and technology, the performance of PDA has been rapidly improved.In the 1990s,Europe and AmericaOpen PDAs began to appear, most people call them handheld computers.
The biggest feature of handheld computer is that it hasOpenIt supports software and hardware upgrading, integrates information input, storage, management and transmission, and has common office, entertainmentmobile communicationAnd other powerful functions.Therefore, PDA can be called aMobile Office。A typical PDA has a touch screen for navigationdata storage OfMemory card slotAnd IrDA,BluetoothAnd/orWi-Fi[8]。Of course, not all PDAs have all the above functions;Even if it does, it may not be realized due to the lack of corresponding services.But it can be predicted that the trend and tide of PDA development is the integration of computing, communication, network, storage, entertainment, e-commerce and other multi-function.
In fact, there is no exact definition of a handheld computer. Some people call notepad a handheld computer. Generally, a handheld computer is a computer withPalmOS, Windows CE or other open operating systems, with network functions, and users can freely upgrade software and hardware.In other words, in addition to extending hardware, users can also add software or even install their ownDevelopment programRun on it.
In use, it is better thanDesktop computerIt is simple to operate, convenient to move, and practical in function. It eliminates the five limitations of desktop computers, namely, the limitations of mobility, the complexity of use, the difficulty of mobile networking, the high price, and the idleness of use[1]。
Basic classification
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Industrial PDAincludeBar code scanner、RFIDReaders and writers, etc.The industrial grade PDA is characterized by its ruggedness and durability, which can be used in many harsh environments. At the same time, it has made many optimizations for industrial use.Catchwell CW30 industrial PDA can support both RFID reading and writing and barcode scanning functions, and has IP54 industrial grade. These are consumer productsHandheld terminalNot available.
Bar code scanner, also known as barcode readerBarcode scanning gun、Bar code scanner、bar codeScanning gunandBarcode reader。It is used to read the barcode[2]The information reading device uses the optical principle to decode the content of the barcodedata lineOr it can be transmitted to the computer or other devices wirelessly.It is widely used in supermarkets, logistics express delivery, libraries, etc. to scan the barcode of goods and documents.
Barcode scanner, also known as barcode scanner/reader, is a device used to read information contained in barcode, which can be divided into one-dimensionaltwo-dimensionalBar code scanner.The structure of barcode scanner usually includes the following parts: light source, receiving devicephotoelectric conversion Components, decoding circuitcomputer interface。The basic working principle of the scanning gun is: the light emitted by the light source passes throughoptical system Illuminates on the bar code symbol, and the reflected light is imaged on thePhotoelectric converterUpper meridiandecoderExplain that the computer can directly acceptdigital signal。In addition to the classification of two-dimensional barcode scanner, it can also be classified as:CCD, full angle laser and laser handheld barcode scanner.
Radio Frequency Identification (RFID) technology, also known asElectronic tagRadio frequency identification is a kind ofcommunications technologyIt can identify specific targets and read and write relevant data through radio signals without establishing mechanical or optical contact between the identification system and specific targets.Commonly used are low frequency (125k~134.2K), high frequency (13.56Mhz)UHF, passive technology, etc.RFID reader writerIt is also divided into mobile and fixed, RFIDTechnology applicationVery wide, such as libraries,Access control system, food safety traceability, etc
UHF PDA
UHF PDA is used to read RFID tags. It has great advantages in reading UHF tags. UHF electronic tags have great advantages in reading and writing distance
Available inDispatcherWaybilldata acquisition,Transfer yard/Warehouse data collection, through scanning the express bar code3G moduleIt can be directly transferred to the background server, and at the same time, it can realize the query of relevant business information and other functions.
2. Logistics distribution
Tobacco distribution is typical,Warehouse inventory、Postal distributionIt is worth developing terminal distribution, drug distribution and large factoryIn plant logisticsTransportation from warehouse to warehouse of logistics company.
3. Chain store/store/counter data collection
It is used for the purchase, sale, storage, inventory, adjustment, return, ordering andMembership managementThe collection and transmission of data such asInventory counting。
Pda order meeting
4. Shoes and clothing order meeting[3]
Used in shoes and clothing industryWireless order meeting, based onWIFIWireless communication technologyOn site order is made by means of scanning bar code on the PDA handheld terminal of Xbond, and the order data is wirelessly transmitted to the background order meeting system. At the same time, query, statistics and analysis functions can be realized.
5. Card Management
Used to manage variousIC cardandContactless IC card, such as ID cardmembership cardwait.As the name implies, card management is to manage various contact/non-contact IC cards, so the main expanded function of the scanning gun it uses is to read and write contact/non-contact IC cards.
The core of palmtop computers is the operating system. The palmtop computers in the market mainly use two types of operating systems: one is the increasingly perfect Palm operating system, and palmtop computers using Palm system in the worldmarket shareAccounting for more than 65%, mainly PalmIBMWorkpadSonyClie, TRGpro, handspring and other palm computersMicrosoftWindows CEAlthough the series started late, it has broken the situation that Palm OS dominates the world. Moreover, because of the extensive licensing of Win CE, most handheld computers in China use the Win CE system, including domesticassociation、FounderAnd overseasHP、COMPAQAnd other companies have launched Windows CE handheld computers.As two major operating systems, PalmOS products are adoptedBattery lifeLonger than the products using Win CE;The product with color display does notMonochrome displayThe battery life of the product is long;In terms of multimedia performance, Win CE is better than Palm;In terms of operation interface and application performance,winceIt can make it easier for users to get started;In addition, Palm has more software than Win CE[4]。
Of course, in addition to the above two major operating systemsinternational marketLook, the operating system of the handheld computerPocket PC、EPOC、Hopen、PenbexandLinuxOperating system.
Three camps
The operating system can be divided into three camps:LinuxOS，Palm OS，Windows Mobile(Pocket PC)。Palm adopts the PalmOS systemPalm Inc development;andPocketPCuseWinCEA series of systems developed by Microsoft.Because of the differences in body performance and system, the two bodies are quite different.
LinuxOS is common in electronic notepad. Although it is an electronic notepad, it has more or less added many intelligent elements. It is also the ancestor of handheld computers. Common models:ShangwutongCelebrity SHARP, Wenqu Star, Haoyitong, etc. In short, people who play handheld computers used to play electronic notebooks, but they are too diverse and lack standardsContinuityIt is not really a notepad.
Pocket PC
Palm using Palm OS and Pocket PC using Microsoft Windows Mobile (PPC).PPC uses Microsoft's operating system. From WINCE to today's WINDOWS MOBLIE 5.0, the time for PPC to participate in PDA is shorter than PALM, but with the ease of use of its operating system (andwindowsThe desktop system is very similar to) and quickly accepted by everyone, and the price is almost the same as PALM, so its market share has expanded rapidly.
PPC generally adopts high-speed CPU, which is generally above 200MHz (due to its large application software volume),Multimedia functionIt is relatively strong. All products adopt color screen design, which is suitable for a wide range of people.But the disadvantages are also very obvious. The waiting time for power is relatively short. Because its powerful CPU and multimedia functions are large consumers of power, although after years of improvementBattery capacityIt keeps increasing, but the waiting time for power is not significantly improved. Generally, a new PPC can run for 5-7 hours at a time after fully charged (depending onindividual differenceInstead of).
Palmer PALM, which appeared earlier and had simple functions in the early days, only stored some personal information, but quickly led a wave of craze, sweepingAmericaAnd Europe.Because the early products do not pay attention to multimedia, the CPU speed is generally lower than 33MHz, but its application software is no weaker than PPC (because the application software is small, andOperation requirementsLow)[5]。
Product Functions
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basic function
Features of Pocket PC
Just like the name "palmtop", it is similar to our desktop in many ways.For example, it also hasCPU、storage、Display chipAnd operating system.And aspersonal computeryesMacThe PDA also has Palm andPPCThe main difference is the operating system.However, the functions of PDA are basically the same, which can mainly be used to remember thingsdocuments editing, play games, play multimedia, use built-in or externalwireless network adapterInternet access, etc.And through manyThird party software, still can seee-book、image processingExternal connectionGPSCard navigation, etc.
“recorder”It can record the content of the meeting, record the words of the interviewee, and leave every happy song and laughter in life."Voice recorder" has two recording formats: PCM and Mobile Voice, in which the Mobile Voice format can record voice for several hours.
Functions of English Chinese English Dictionary
Pocket PC
“Pocket dictionary”Including 150000 yuanvocabularyEnglish Chinese EnglishBidirectional dictionary, either throughEnglish wordsCheck the Chinese meaning, or write it into Chinese to find the corresponding English expression.If you want to memorize words, start from a. The words and phrases here are enough to make you reach the vocabulary of TOFEL and GRE.
Global clock comparison function
In the "Global Clock", you can find the time of more than 100 countries and regions around the world, as well as the name of the takeoff airport, sunrise and sunset time, and telephone numberArea codeAnd kilometers away from Beijing.
Reminder function
The handheld computer provides a variety of reminder functions, includinglight-emitting diodeFlashing reminder, vibration reminder, sound reminder, and screeninformation display Reminder.Different sounds can also be set for the voice reminder.When setting reminders, you can select how long to execute reminders in advance.
Leisure and entertainment functions
People can't always work. What can they do to relax their nerves when they are free? Pocket computers provide a variety of leisure and entertainment functions to suit users with different personalities and hobbies.
As long as you have theFax software, thenModem/FaxFaxThe function can be realized.
Detailed configuration
1. Built inspeaker
Built in speakerIt refers to the built-in speaker of the handheld computer. Users can not only listen to the sound from the PDA through the headphone jack, but also through the built-in speaker.
MicrophoneIt's the handheld computer that collects the sound sourceinput deviceone of.The built-in microphone of the PDA is relatively small.
3、Batterytype
The handheld computer needs batteries to maintain normal operation, and the handheld computer usesLithium ion batteryorAlkaline batteryAs its power supply, few handheld computers use alkaline batteries as their power supply, such as ACER S10, PLAM M100, SONY PEG SL-10, etc. Most handheld computers use lithium ion batteries as their power supply.
The handheld computer has a variety of text input methods, including Englishkeyboard entry，Handwriting input , Pinyin input,Symbol keyboardInput and direct handwriting input, there are two input methodsMonster Chinese Commonly used with external Chinese system
As a small portable digital device, the handheld computer has the advantages of convenient carrying and powerful functions, but its storage capacity is not large. From time to time, the files in the handheld computer need to be stored in the computer, which involvesConnection modeProblems.Data transmission interface is the interface between handheld computer and personal computer and other devices.With this interface, the PDA and other devices can achieve upload, download, data synchronization and other functions.Common PDAData transmission interfaceyesUSB interface, serial portInfrared interfaceandBluetoothInterfaces, etc.
In brief, the resolution of the display screen refers to the ability of the display screen to analyze images. The higher the resolution is, the clearer the image displayed on the display screen will be.For example, the early Palm models have always used a monochrome 160 × 160 resolution, which means that there are 160 pixels in both horizontal and vertical directions on the display screen.The general resolution of color display screen is 240 × 320, 320 × 320, etc.
Bluetooth(Bluetooth) is used to replace someElectronic equipmentShort distance of cable or connection used onWireless connectionTechnology.The "Bluetooth" technology can effectively simplify the handheld computerNotebook computerAnd mobile phonesmobile communicationterminal equipmentThe communication between these devices and the Internet can also be successfully simplified, so that the data transmission between these devices and the Internet becomes more rapid and efficient.haveBluetooth functionThere are many types of handheld computers. I believe that with the gradual development of handheld computers, Bluetooth will become a common function of handheld computers.But at present, handheld computers with Bluetooth function are more expensive.The handheld computer can also realize wireless connection with other devices that also have Bluetooth interfaces by using the Bluetooth interfacedirectionalLimit, effective connection distance up to 10m, generaltransmission speed All have the advantages of 1M, fast up to 10M or even faster, but there are not many electronic devices configured with Bluetooth interfacePenetration rateThere is a big gap, which is a pity. However, computers without Bluetooth interface can be installed byBluetooth adapterTo realize the Bluetooth interface function, these Bluetooth adapters are generally USB interfaces, which can be plugged into the USB interface of the computer for use, and onlyflash discSize, carrying far more thandata lineBe convenient.
With a handheld computer, you can not only writeEmail, and it can be sent immediately. There is no external line connected to the PC, and everything is transmitted by the Bluetooth device.In this way, you can use the handheld computer to write email on the plane. When the plane lands, you just need to turn on your mobile phone, and all information can be automatically sent through the airport's Bluetooth device.With Bluetooth technology, your handheld computer can keep in sync with the desktop system.
Pocket PClcdThe quality of the screen is not only related to the comfort of the handheld computer, but also an important aspect of the performance of the handheld computer.LCD display for handheld computer color is divided into:transmissionThere are three types of handheld computers, namely, transmissive, reflective and transmissive. Most handheld computers use the latter two types of displays, while transmissive LCD displays belong to the technology used by early PDAs, and are rarely used in newly launched handheld computers.
9、camerafunction
Pocket PC
PalmtopCamera functionIt refers to that the handheld computer can realizeTake photos, recording short films andNetwork videoFunction of.The combination of this function and the handheld computer can bring users more convenient and practical choices.As an emerging function of the handheld computer, the pixels of the built-in or external camera of the handheld computer are relatively low, generally around 300000 pixels.Display color
Generally, palmtop computers use two kinds of screens: color display screen and monochrome display screen.Early Palm handheld computers and PDAs produced by domestic manufacturers often used monochrome design.From a practical point of view, unless you plan to view pictures on a PDA, it is not necessary to purchase a color display PDA, because color displays consume more power and are more expensive.Effectiveness of general color display screenRun TimeBetween 6 and 8 hours,Monochrome displayCan be used for up to 30 hours.Of course, the handheld computer with color display screen looks more fashionable and stylish.How to choose depends on your personal hobbies and economic strength.
10. Pocket PC compatible operating system
The index of compatible operating system isDriverWhether it can be compatible with various operating systems in the market, such aswindows98、windows2000、windowsXP、MAC OS, LINUX and other operating systems.The more perfect the driver of a handheld computer supports the operating system, the more convenient it will be to install and use. This is also a major indicator to measure the new handheld computer.
The palmtop's memory is generally divided intoROM(read only memory) andRAM（random access memory），Read only memory ROMThere is a solidified operating system,Remaining capacityCan be usedStore dataRAM is mainly used to store data and run programs.The full name of RAM (Random Access Memory) is random access memory, which is equivalent to theRemovable Storage, used to store and save data.It can be read and written at any time. RAM is usually used as a temporary part of the operating system or other running programsstorage medium (can be calledsystem memory）。
However, when the power is turned off, RAM cannot retain data. If data needs to be saved, it must be written to a long-term memory (such as a hard disk).Because of this, RAM is sometimes called "variable memory".RAM memoryIt can be further divided into static RAM（SRAM）AndDynamic memory（DRAM）Two categories.DRAM is widely used as the main memory of the system because of its low price per unit capacity.
Compared with ROM, the biggest difference between RAM and ROM is that the data saved on RAM will disappear automatically after power failure, while ROM will not.4~8M RAM for generalapplication programThe operation of is enough, if we pursueMultimedia function64M RAM capacity is only a basic requirement.
Product category
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Related introduction
PDA in a narrow sense can be calledElectronic NotepadIts function is relatively simple, mainly managing personal information, such asmail list, notes and notesSchedule、Notes, calculator, recording and dictionary.Moreover, these functions are fixed, and new functions cannot be added according to user requirements.In a broad sense, PDA mainly refers to palmtop computers, including other small digital devices with similar functions.The term "handheld computer" has different interpretations.The handheld computer in a narrow sense does not have a keyboard, and usesHandwriting input 、Voice inputorsoft keyboardEnter.In a broad sense, palmtop computers include both those without keyboards and those with keyboards.However, in the Chinese market, almost all handheld computers do not have keyboards.PDA should be subdivided intoElectronic dictionary, PDA, handheldComputer equipmentAnd personal communication assistant.The latter two have gradually merged due to the development of technology and market.
Pocket PC
Usually, the digital world will only call this kind of handheld computer PDA, which also represents the true meaning of PDA.Because it is almost ordinaryHome computerAll functions of.The biggest feature of handheld computers is that they have their own operating system, which is usually fixed inROMIn.Its adoptedstorage deviceMost of them are expensive IC flash memory, with a capacity of about 16MB.Handheld computers generally do not have a keyboard. Handwritten and soft keyboard input modes are used, and standard serial portsinfraredAccess mode and built-in MODEM to facilitatepersonal computerConnect and surf the Internet.The biggest difference between the handheld computer and the previous products is itsapplication programThe scalability of.Based on their respective operating systems, anyone can useprograming languageDevelop corresponding applications.You can also install and uninstall on your handheld computer.Due to its complete functions, it is also complex in operation, and is not suitable for beginners who do not know much about computers.
Handheld computer
The English name of handheld computer device isHPC, which means HandeldPC.This is a kind ofNotebook computerAnd handheld computers.But why do you say that?Because it has a handheld computer common operating system, but it is equipped with a small keyboard.Its appearance is similar to the traditional notebook computer.Its function is more powerful than that of a handheld computer, but its size and weight also increase, so its portability is worse than that of a handheld computer.
Communication Assistant
The personal communication assistant machine is the most fashionable one among so many kinds of products.Its concept is to combine some functions of handheld computers with those of mobile phonesbeeperResulting from combination.The biggest feature of this product is that it abandons the generalTelephone lineThe wireless data receiving mode makes the product more adaptable.Although the early products were designed with mobile phones as the starting point, their business functions were obviously inferior to those of ordinary handheld computers, only equivalent to the functions of ordinary electronic notepads. The products developed based on WinCE system and Palm are collectively referred to asSmartPhone, its function is equal to or higher than that of the handheld computer, and it also has communication function and wirelessData exchangeAnd represents the development direction of handheld computers in the future.
Model defects
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The world's first PDA
But the disadvantages are also very obvious: the waiting time for power is short (5-8 hours),Third party softwareNot stable enough.Classic models: h565 ipaq3630 ipaq3970 ipaq4150 ipaq4700 ipaq5550 a600 e740 n560 axim50, etc.PentiumPALM, later than Linux OS, earlierfunctional comparisonIt's simple. It's just to store some personal information (phone calls, notes,Personal financial managementAh), but it quickly led a frenzy that swept throughAmericaAnd Europe.As the early products did not pay attention to multimediaCPUThe speed is relatively low, generally within 33MHz, but its application software is no weaker than PPC (its softwareoperating efficiency And stability).And the super long power waiting capacity really makes PPC look bad (take the PALM M500 for example, black and white screen, low machine configuration, continuousRun TimeIt can last for more than 20 hours. It can be used for about 3 hours every day, and can be recharged after about 10 days).PALM also began to pay attentionMultimedia functionAnd began to produce something similar toPPCAs the starting configuration of the high-speed machine becomes higher, the power waiting capacity starts to decline rapidly, which is basically the same as PPC[6]。
Classic model
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Classic computer[7]vx palm m100 palm m515 palm te palm tx ibm c500 clie800 clie nz90treo90 treo600 treo 650。
Development trend
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From a macro perspective, PDA will have the followingDevelopment trend：
PDA products mostly use special chargers for PDA to provide energy, which must be incompatible with each other. Ordinary batteries cannot support or consume electricity very quickly. If the use of PDA is made more convenient, the demand of PDA for electric energy will also become diversified, and it needs to make progress in energy consumption. For example, equipment for storing electric energy can supply power to PDA, such asAutomobile battery, watch batterySolar cellAnd any other possible form of electrical energy.
2. Wireless data transmission
conventionalTransmission lineThere are length restrictions and certain requirements for the location of equipment. The transmission line is not easy to arrange, inconvenient to carry, and unsightly.Via Bluetoothwireless network, which can make the connection between PDA and computer more convenient, or conduct Web browsing, orDownload a softwareSo that users can conveniently and timely carry outData exchangeandInformation exchange。
3. Integrating multiple functions
PDAIt is developing towards the trend of multi-function integration of computing, communication, network, storage, entertainment, e-commerce, professional applications, etc.In particular, the combination of PDA and mobile phone functions is favored by more and more high-end users and is gradually becoming an international mobile phoneEnd marketNew trends and mainstream forces, and gradually towards socialization and standardization.
China Internet of Things School Enterprise AllianceIt is believed that the PDA market contains unlimited business opportunities and potentialCorporate GroupThey are striving to develop PDA in the direction they want.In the mainland, the mobile phone market is basically overseasMotorola、NOKIA、EricssonThe PDA market is dominated by domestic manufacturers.Therefore, China needs to seize the opportunity and strive for a place in this competition[2]。
