INDUSTRIAL TRAINING REPORTONREAL TIME CONCEPTS OF SOFTWARE AND NETWORKING DOMAINPartial Fulfillment ofB. Tech Computer Science & EngineeringSubmitted byS ABINAYA Reg. No: 1031240070III Year, CSE DepartmentUndergone training atHCL Career Development Centre,ChennaiSubmitted toMrs.Niveditha B.E,M.E,MIETAsst. Prof. CSE

Department of Computer Science & Engineering SRM UniversityCERTIFICATE

This is to certify that S.Abinaya, Register number 1031240070,B.Tech (CSE), III year Student of SRM University, Vadapalani, Chennai has successfully completed her Industrial Training Program from 14 December 2013 to 28 December 2013 (15 days) as partial fulfillment of B.Tech Course.

Course Coordinator Head of the DepartmentMrs.Niveditha B.E,M.E,MIET Mrs.B.Padmavathi B.E,M.E, (PHD)Asst. Prof., CSE HOD, CSE

ACKNOWLEDGEMENTI want to thank HCL Career Development Centre, Chennai for providing me with an opportunity to do an inplant training in their organization. I wish to thank all my guides over there for helping me complete the training by providing me with valuable inputs.I would like to thank Mrs.B.Padmavathi HOD, CSE, SRM University, Vadapalani, for the constant encouragement and support she gave to the students to take up innovative projects and training courses.I wish to extend my gratitude to Mrs.Niveditha, Asst. Professor,CSE, for her constant advice on the various course-related issues.

INDEXS. No.TopicPage

1Certificate1

2Inplant Training Certification Letter2

3Acknowledgements3

4About the company5

5Abstract6

6WiFi,OSI Model7

72G,3G,4G15

8RJ4520

9Skinput technology22

10Embedded Systems23

11Micro controllers27

12Serial communications28

13References30

ABOUT THE COMPANY HCL Learning Ltd. is a 100% owned subsidiary of HCL InfosPystems Ltd. HCL Learning covers the entire spectrum of education and training requirements across schools, colleges, individuals and enterprises. HCL Learning addresses the education and training needs through 2 business verticals:K-12Higher Education & Enterprise LearningHCL Career Development Centre (CDC) is the training arm of HCL Learning Ltd. It offers a complete spectrum of quality training programs on software, hardware, networking, industrial /project training and various other new-age courses as per the trends & demands of the industry.It offers training for individuals,engineering colleges and polytechnichnics.It also offers corporate trainings and government trainings.At CDC we believe that the students should be given a hand on experience and thus all our courses are a blend of Theoretical and practical implementation .HCL CDC also offers global certifications in association with leading organizations worldwide.Course curriculum has been designed in a manner to increase the employability factor of the students. Under the aegis of HCL and strong associations within the industry CDC is able to provide better placement opportunities to the students.

ABSTRACTNetworking encompasses a variety of tasks related to the communication of information on networks; it has a substantial economic and societal impact on a broad range of areas including transportation systems, wired and wireless communications and a range of Internet applications. As transportation and communication networks become increasingly more complex, the ever increasing demand for congestion control, higher traffic capacity, quality of service, robustness and reduced energy consumption requires new tools and methods to meet these conflicting requirements. The new methodology should serve for gaining better understanding of the properties of networking systems at the macroscopic level, as well as for the development of new principled optimization and management algorithms at the microscopic level.We have new introductions like 3G,4G,wi-fi technology etc.. Also here our report includes about new sensor technology and about OSI layers. The report also explains about Embedded systems and micro controller serial communication.Embedded systems are often distributed and deployed in various environments. Wireless sensor nodes deposited in various places provide light, temperature, humidity, and other measurements. Wireless nodes attached to circuits or appliances sense the current or control the usage. Wireless sensor networks are application-specific. Because of this they have to involve both software and hardware. They also use protocols, which relate to both the application and wireless network. The applications using wireless sensor networks are the consumer devices supporting multimedia applications, for example, personal digital assistants, network computers, and mobile communication devices. Emerging embedded systems run multiple applications such as Web-browsers, audio and video communication applications. We describe design issues in wireless networks to support sensors and embedded systems communication and information processing. Also here we can see about various types of connectors.This review aims at presenting an overview of tools and methods that have been developed today.

WiFiHISTORY OF WIFIWi-Fi, also spelled Wifi or WiFi, is a local area wireless technology that allows an electronic device to exchange data or connect to the internet using 2.4GHz UHF and 5GHz SHF radio waves. Full form of WiFi is Wireless Fidelity.The name is a trademark name, and is a play on the audiophile term Hi-Fi. The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard.However, since most modern WLANs are based on these standards, the term "Wi-Fi" is used in general English as a synonym for "WLAN". Only Wi-Fi products that complete Wi-Fi Alliance interoperability certification testing successfully may use the "Wi-Fi CERTIFIED" trademark.Many devices can use Wi-Fi, e.g., personal computers, video-game consoles, smartphones, some digital cameras, tablet computers and digital audio players.Hotspot coverage can comprise an area as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.Wi-Fi can be less secure than wired connections because an intruder does not need a physical connection. Web pages that use SSL are secure but unencrypted internet access can easily be detected by intruders. Because of this, Wi-Fi has adopted various encryption technologies.An optional feature added in 2007, called Wi-Fi Protected Setup (WPS), had a serious flaw that allowed an attacker to recover the router's password. The Wi-Fi Alliance has since updated its test plan and certification program to ensure all newly certified devices resist attacks.UsesHaving the ability to connect to the internet anywhere we go is undoubtedly awesome, but it isn't the only gift Wi-Fi technology has given us. Here are our 10 favorite uses for Wi-Fi that go beyond accessing the web.1) Sync Your Music Library, Photo Library, or Other Files with Your Smartphone2) Tell Your Phone When Its Home (or Not)3) Wirelessly Transfer Photos from Your Digital Camera4) Stream Audio to Any Speakers in the House5) Share Files with Nearby ComputersAdvantagesWi-Fi allows cheaper deployment of local area networks (LANs). Also spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.Manufacturers are building wireless network adapters into most laptops. The price of chipsets or Wi-Fi continues to drop, making it an economical networking option included in even more devices.Different competitive brands of access points and client network-interfaces can inter-operate at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards compatible. Unlike mobile phones, any standard Wi-Fi device will work anywhere in the world.Wi-Fi Protected Access encryption (WPA2) is considered secure, provided a strong passphrase is used. New protocols for quality-of-service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video). Power saving mechanisms (WMM Power Save) extend battery life.LimitationsSpectrum assignments and operational limitations are not consistent worldwide: Australia and Europe allow for an additional two channels beyond those permitted in the US for the 2.4GHz band (113 vs. 111), while Japan has one more on top of that (114).A Wi-Fi signal occupies five channels in the 2.4GHz band. Any two channel numbers that differ by five or more, such as 2 and 7, do not overlap. The oft-repeated adage that channels 1, 6, and 11 are the only non-overlapping channels is, therefore, not accurate. Channels 1, 6, and 11 are the only group of three non-overlapping channels in North America and the United Kingdom. In Europe and Japan using Channels 1, 5, 9, and 13 for 802.11g and 802.11n is recommended.Equivalentisotropically radiated power (EIRP) in the EU is limited to 20 dBm (100mW).The current 'fastest' norm, 802.11n, uses double the radio spectrum/bandwidth (40MHz) compared to 802.11a or 802.11g (20MHz). This means there can be only one 802.11n network on the 2.4GHz band at a given location, without interference to/from other WLAN traffic. 802.11n can also be set to use 20MHz bandwidth only to prevent interference in dense community.Many newer consumer devices support the latest 802.11ac standard, which uses the 5GHz band and is capable of multi-station WLAN throughput of at least 1 gigabit per second. According to a study, devices with the 802.11ac specification are expected to be common by 2015 with an estimated one billion spread around the world.Data security risksThe most common wireless encryption-standard, Wired Equivalent Privacy (WEP), has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2) encryption, which became available in devices in 2003, aimed to solve this problem. Wi-Fi access points typically default to an encryption-free (open) mode. Novice users benefit from a zero-configuration device that works out-of-the-box, but this default does not enable any wireless security, providing open wireless access to a LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI). On unencrypted Wi-Fi networks connecting devices can monitor and record data (including personal information). Such networks can only be secured by using other means of protection, such as a VPN or secure Hypertext Transfer Protocol over Transport Layer Security (HTTPS).Network SecurityThe main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as Ethernet. With wired networking, one must either gain access to a building (physically connecting into the internal network), or break through an external firewall. To enable Wi-Fi, one merely needs to be within the range of the Wi-Fi network. Most business networks protect sensitive data and systems by attempting to disallow external access. Enabling wireless connectivity reduces security if the network uses inadequate or no encryption.An attacker who has gained access to a Wi-Fi network router can initiate a DNS spoofing attack against any other user of the network by forging a response before the queried DNS server has a chance to reply.Securing methodsA common measure to deter unauthorized users involves hiding the access point's name by disabling the SSID broadcast. While effective against the casual user, it is ineffective as a security method because the SSID is broadcast in the clear in response to a client SSID query. Another method is to only allow computers with known MAC addresses to join the network, but determined eavesdroppers may be able to join the network by spoofing an authorized address.Wired Equivalent Privacy (WEP) encryption was designed to protect against casual snooping but it is no longer considered secure. Tools such as AirSnort or Aircrack-ng can quickly recover WEP encryption keys. Because of WEP's weakness the Wi-Fi Alliance approved Wi-Fi Protected Access (WPA) which uses TKIP. WPA was specifically designed to work with older equipment usually through a firmware upgrade. Though more secure than WEP, WPA has known vulnerabilities.The more secure WPA2 using Advanced Encryption Standard was introduced in 2004 and is supported by most new Wi-Fi devices. WPA2 is fully compatible with WPA.A flaw in a feature added to Wi-Fi in 2007, called Wi-Fi Protected Setup, allows WPA and WPA2 security to be bypassed and effectively broken in many situations. The only remedy as of late 2011 is to turn off Wi-Fi Protected Setup,[which is not always possible.PiggybackingPiggybacking refers to access to a wireless Internet connection by bringing one's own computer within the range of another's wireless connection, and using that service without the subscriber's explicit permission or knowledge.During the early popular adoption of 802.11, providing open access points for anyone within range to use was encouraged to cultivate wireless community networks, particularly since people on average use only a fraction of their downstream bandwidth at any given time.Recreational logging and mapping of other people's access points has become known as wardriving. Indeed, many access points are intentionally installed without security turned on so that they can be used as a free service. Providing access to one's Internet connection in this fashion may breach the Terms of Service or contract with the ISP. These activities do not result in sanctions in most jurisdictions; however, legislation and case law differ considerably across the world. A proposal to leave graffiti describing available services was called warchalking A Florida court case determined that owner laziness was not to be a valid excuse.Piggybacking often occurs unintentionally, since most access points are configured without encryption by default and operating systems can be configured to connect automatically to any available wireless network. A user who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without any visible indication. Moreover, a user intending to join one network may instead end up on another one if the latter has a stronger signal. In combination with automatic discovery of other network resources (see DHCP and Zeroconf) this could possibly lead wireless users to send sensitive data to the wrong middle-man when seeking a destination (see Man-in-the-middle attack). OSI MODELIntroductionThe Open Systems Interconnection model (OSI) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO), maintained by the identification ISO/IEC 7498-1.The model groups communication functions into seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path. Two instances at one layer are connected by a horizontal connection on that layer.

Description of OSI layersAt each level (N), two entities (layer N peers) exchange protocol data units (PDUs) by means of a layer-N protocol. A service data unit (SDU) is the payload of a PDU, transmitted unchanged to a peer.The SDU is a unit of data that is passed down from one OSI layer to the next-lower layer, and which the lower layer encapsulates into a PDU. Layer N-1 adds a header or a footer, or both, to the SDU, composing a PDU of layer N-1. The added framing make it possible to get the data from a source to a destination. The PDU at a layer N thus becomes the SDU of layer N-Some orthogonal aspects, such as management and security, involve every layer.Security services are not related to a specific layer: they can be related by several layers, as defined by ITU-T X.800 Recommendations.These services are aimed to improve the CIA triad (confidentiality, integrity, and availability) of transmitted data. In practice, the availability of communication service is determined by the interaction between network design and network management protocols. Appropriate choices for both of these are needed to protect against denial of service.OSI Model

Data unitLayerFunction

HostlayersData7. ApplicationNetwork process to application

6. PresentationData representation, encryption and decryption, convert machine dependent data to machine independent data

5. SessionInterhost communication, managing sessions between applications

Segments4. TransportReliable delivery of packets between points on a network.

MedialayersPacket/Datagram3. NetworkAddressing, routing and (not necessarily reliable) delivery of datagrams between points on a network.

Bit/Frame2. Data linkA reliable direct point-to-point data connection.

Bit1. PhysicalA (not necessarily reliable) direct point-to-point data connection.

Layer 1: physical layerThe physical layer has the following major functions: it defines the electrical and physical specifications of the data connection. It defines the relationship between a device and a physical transmission medium (e.g., a copper or fiber optical cable). This includes the layout of pins, voltages, line impedance, cable specifications, signal timing, hubs, repeaters, network adapters, host bus adapters (HBA used in storage area networks) and more. it defines the protocol to establish and terminate a connection between two directly connected nodes over a communications medium. it may define the protocol for flow control. it defines transmission mode i.e. simplex,half,full duplex it defines topology it defines a protocol for the provision of a (not necessarily reliable) connection between two directly connected nodes, and the modulation or conversion between the representation of digital data in user equipment and the corresponding signals transmitted over the physical communications channel. This channel can involve physical cabling (such as copper and optical fiber) or a wireless radio link.

Layer 2: data link layerThe data link layer provides a reliable link between two directly connected nodes, by detecting and possibly correcting errors that may occur in the physical layer. The data link layer is divided into two sublayers: Media Access Control (MAC) layer - responsible for controlling how computers in the network gain access to data and permission to transmit it. Logical Link Control (LLC) layer - control error checking and packet synchronization.Layer 3: network layerThe network layer provides the functional and procedural means of transferring variable length data sequences (called datagrams) from one node to another connected to the same network. A network is a medium to which many nodes can be connected, on which every node has an address and which permits nodes connected to it to transfer messages to other nodes connected to it by merely providing the content of a message and the address of the destination node and letting the network find the way to deliver ("route") the message to the destination node. In addition to message routing, the network may (or may not) implement message delivery by splitting the message into several fragments, delivering each fragment by a separate route and reassembling the fragments, report delivery errors, etc.Layer 4: transport layerThe transport layer provides the functional and procedural means of transferring variable-length data sequences from a source to a destination host via one or more networks, while maintaining the quality of service functions.An example of a transport-layer protocol in the standard Internet stack is Transmission Control Protocol (TCP), usually built on top of the Internet Protocol (IP).Layer 5: session layerThe session layer controls the dialogues (connections) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for full-duplex, half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart procedures.Layer 6: presentation layerThe presentation layer establishes context between application-layer entities, in which the application-layer entities may use different syntax and semantics if the presentation service provides a big mapping between them. If a mapping is available, presentation service data units are encapsulated into session protocol data units, and passed down the protocol stack.Layer 7: application layerThe application layer is the OSI layer closest to the end user, which means both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model.2G2G(or2-G) is short for second-generationwirelesstelephonetechnology. Second generation 2G cellular telecom networks were commercially launched on theGSMstandard inFinlandbyRadiolinja(now part ofElisa Oyj) in 1991.Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted; 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting withSMStext messages. 2G technologies enabled the various mobile phone networks to provide the services such as text messages, picture messages and MMS (multi media messages). All text messages sent over 2G are digitally encrypted, allowing for the transfer of data in such a way that only the intended receiver can receive and read it.After 2G was launched, the previous mobile telephone systems were retrospectively dubbed1G. While radio signals on 1G networks areanalog, radio signals on 2G networks aredigital. Both systems use digital signaling to connect the radio towers (which listen to the handsets) to the rest of the telephone system.2G has been superseded by newer technologies such as2.5G,2.75G,3G, and4G; however, 2G networks are still used in many parts of the world.CapacityUsingdigital signalsbetween the handsets and the towers increasessystem capacityin two key ways: Digital voice data can be compressed and multiplexed much more effectively than analog voice encodings through the use of variouscodecs, allowing more calls to be transmitted in same amount of radiobandwidth. The digital systems were designed to emit less radio power from the handsets. This meant thatcellshad to be smaller, so more cells had to be placed in the same amount of space. This was possible becausecell towersand related equipment had become less expensive.2G Data Transmission Capacity: With GPRS (General Packet Radio Service), you have a theoretical transfer speed of max. 50 kbit/s (40 kbit/s in practice). With EDGE (Enhanced Data Rates for GSM Evolution), you have a theoretical transfer speed of max. 250 kbit/s (150 kbit/s in practice).Disadvantages In less populous areas, the weaker digital signal transmitted by a cellular phone may not be sufficient to reach a cell tower. This tends to be a particular problem on 2G systems deployed on higher frequencies, but is mostly not a problem on 2G systems deployed on lower frequencies. National regulations differ greatly among countries which dictate where 2G can be deployed. Analog has a smooth decay curve, but digital has a jagged steppy one. This can be both an advantage and a disadvantage. Under good conditions, digital will sound better. Under slightly worse conditions, analog will experience static, while digital has occasionaldropouts. As conditions worsen, though, digital will start to completely fail, by dropping calls or being unintelligible, while analog slowly gets worse, generally holding a call longer and allowing at least some of the audio transmitted to be understood.Advantage While digital calls tend to be free ofstaticandbackground noise, thelossy compressionthey use reduces their quality, meaning that the range of sound that they convey is reduced. Talking on a digital cell phone, a caller hears less of the tonality of someone's voice.2G Shut downVarious carriers such as AT&T have made announcements that 2G GSM technology in the United States is in the process of being shut down so that carriers can reclaim those radio bands and re-purpose them for future technology needs. The shut down will be complete by the end of 2016. All 2G GSM devices will lose service at some point between now and the end of 2016. This shut down is having a notable impact on the electronic security industry where many 2G GSM radios are in use for alarm signal communication to Central Station dispatch centers. 2G GSM radios must be replaced by newer generation radios to avoid service outages. 3G3G, short form ofthird Generation, is thethird generation of mobile telecommunications technology.This is based on a set of standards used for mobile devices and mobile telecommunications use services and networks that comply with theInternational Mobile Telecommunications-2000 (IMT-2000)specifications by theInternational Telecommunication Union. 3Gfinds application in wireless voicetelephony,mobile Internetaccess,fixed wirelessInternet access,video callsandmobile TV.3G telecommunication networks support services that provide an information transfer rate of at least 200kbit/s. Later 3G releases, often denoted3.5Gand3.75G, also providemobile broadbandaccess of severalMbit/stosmartphonesandmobile modemsin laptop computers. This ensures it can be applied to wireless voicetelephony,mobile Internetaccess,fixed wirelessInternet access,video callsandmobile TVtechnologies.A new generation of cellular standards has appeared approximately every tenth year since1Gsystems were introduced in 1981/1982. Each generation is characterized by new frequency bands, higher data rates and nonbackward-compatible transmission technology. The first 3G networks were introduced in 1998 and fourth generation "4G" networks in 2008.FeaturesData ratesITU has not provided a cleardefinition of the data rate that users can expect from 3G equipment or providers. Thus users sold 3G service may not be able to point to a standard and say that the rates it specifies are not being met. While stating in commentary that "it is expected that IMT-2000 will provide higher transmission rates: a minimum data rate of 2Mbit/s for stationary or walking users, and 384kbit/s in a moving vehicle," the ITU does not actually clearly specify minimum required rates, nor required average rates, nor what modesof the interfaces qualify as 3G, so variousdata rates are sold as '3G' in the market. Compare with3.5Gand4G.In India, 3G is defined by telecom service providers as minimum 2 Mbit/s to maximum 28 Mbit/s. Security3G networks offer greater security than their 2G predecessors. By allowing the UE (User Equipment) to authenticate the network it is attaching to, the user can be sure the network is the intended one and not an impersonator. 3G networks use theKASUMIblock cipherinstead of the olderA5/1stream cipher. However, a number of serious weaknesses in the KASUMI cipher have been identified. Inaddition to the 3G network infrastructure security, end-to-end security is offered when application frameworks such as IMS are accessed, although this is not strictly a 3G property.Applications of 3GThe bandwidth and location information available to 3G devices gives rise to applications not previously available to mobile phone users. Some of the applications are: Global Positioning System (GPS) Location-based services Mobile TV Telemedicine

4G4G, short forfourth generation, is the fourth generation ofmobile telecommunicationstechnology, succeeding3Gand preceding5G. A 4G system, in addition to the usual voice and other services of 3G, provides mobile broadband Internet access, for example to laptops withwireless modems, tosmartphones, and to other mobile devices. Potential and current applications include amendedmobile webaccess,IP telephony, gaming services,high-definitionmobile TV, video conferencing,3D television, andcloud computing.Two 4G candidate systems are commercially deployed: theMobile WiMAXstandard (first used in South Korea in 2007), and the first-releaseLong Term Evolution(LTE) standard (in Oslo, Norway and Stockholm, Sweden since 2009). It has however been debated if these first-release versions should be considered to be 4G or not, as discussed in thetechnical definitionsection below.In the United States,Sprint(previouslyClearwire) has deployed Mobile WiMAX networks since 2008, whileMetroPCSbecame the first operator to offer LTE service in 2010. USB wireless modems were among the first devices able to access these networks, with WiMAX smartphones becoming available during 2010, and LTE smartphones arriving in 2011. The consumer should note that3Gand 4G equipment made for other continents are not always compatible, because of different frequency bands. Mobile WiMAX is currently (April 2012) not available for the European market.Advantages of 4G The most obvious advantage of the 4G mobile network is its amazing speed. Increased bandwidth leads to much faster data transfer speed, which is especially advantageous for mobile devices. Users of the 4G network get the advantage of superior, uninterrupted connectivity, especially for advanced tasks such as video chats and conferences. Considering the younger generation of mobile device users, they can stream music, videos and movies at a much faster rate than ever before and can also easily share information online. 4G networks offer much more coverage than other systems such asWiFi, which forces users to depend upon hotspots in each area you visit. Since 4G offers a coverage of 30 miles and more, as also overlapping network ranges, users would be assured of complete connectivity at all times.RJ45Aregistered jack(RJ) is a standardized physicalnetwork interfaceboth jack construction and wiring patternfor connecting telecommunications or data equipment to a service provided by alocal exchange carrierorlong distance carrier. The standard designs for these connectors and their wiring are namedRJ11,RJ14,RJ21,RJ35,RJ45,RJ48, etc. Many of these interface standards are commonly used in North America, though some interfaces are used world-wide. It is common to find a dash (hyphen) between the RJ and the number, but the actual standard has no dash or hyphen.The connectors used for registered jack installations are primarily themodular connectorand the 50-pinminiature ribbonconnector types. For example, RJ11 uses a six-position two-conductor connector (6P2C), RJ14 uses a six-position four-conductor (6P4C) modular plug and jack, while RJ21 uses a 25-pair (50-pin) miniature ribbon connector.Registered jacket typesCommon types

6P4C crimp-on style connector commonly used for RJ11 and RJ14.The most commonly recognized registered jack is the RJ11. This is a modular connector wired for one analog telephone line, using the center two contacts of six available positions, and is found in most homes and offices in most countries for single-line telephones. RJ14 is similar to RJ11 but is wired for two lines and RJ25 has three lines. RJ61 is a similar registered jack for four lines. Telephone line cords with modular plugs are intended most often for RJ11 and RJ14.The RJ45(S) jack is rarely used, but the designation RJ45 commonly refers to any8P8C modular connector.List of official registered jacksCodeConnectorUsage

RJ2MB50-pinmicro ribbon212 telephone lines with make-busy arrangement

RJ11(C/W)6P2CFor one telephone line (6P4C if power on second pair)

RJ12(C/W)6P6CFor one telephone line ahead of thekey system

RJ13(C/W)6P4CFor one telephone line behind thekey system

RJ14(C/W)6P4CFor two telephone lines (6P6C if power on third pair)

RJ15C3-pin weatherproofFor one telephone line

RJ18(C/W)6P6CFor one telephone line with make-busy arrangement

RJ21X50-pinmicro ribbonFor up to 25 lines

RJ25(C/W)6P6CFor three telephone lines

SKINPUT TECHNOLOGYSkinputis aninput technologythat uses bio-acoustic sensing to localize finger taps on the skin. When augmented with apico-projector, the device can provide a direct manipulation,graphical user interfaceon the body. The technology was developed by Chris Harrison,Desney Tan, and Dan Morris, atMicrosoft Research's Computational User Experiences Group. Skinput represents one way to decouple input from electronic devices with the aim of allowing devices to become smaller without simultaneously shrinking the surface area on which input can be performed. While other systems, likeSixthSensehave attempted this with computer vision, Skinput employs acoustics, which take advantage of the human body's natural sound conductive properties (e.g.,bone conduction).This allows the body to be annexed as an input surface without the need for theskinto be invasively instrumented with sensors, tracking markers, or other items.Microsofthas not commented on the future of the projects, other than it is under active development. It has been reported this may not appear in commercial devices for at least 2 years.OPERATIONTen channels of acoustic data generated by three finger taps on the forearm, followed by three taps on the wrist. The exponential average of the channels is shown in red. Segmented input windows are highlighted in green. Note how different sensing elements are actuated by the two locations.Skinput has been publicly demonstrated as an armband, which sits on thebiceps. This prototype contains ten small cantilevered Piezo elements configured to be highly resonant, sensitive to frequencies between 25 and 78Hz.This configuration acts like a mechanicalFast Fourier transformand provides extreme out-of-band noise suppression, allowing the system to function even while the user is in motion. From the upper arm, the sensors can localize finger taps provided to any part of the arm, all the way down to the finger tips, with accuracies in excess of 90% (as high as 96% for five input locations).Classification is driven by asupport vector machineusing a series of time-independent acoustic features that act like a fingerprint. Likespeech recognitionsystems, the Skinput recognition engine must be trained on the "sound" of each input location before use. After training, locations can be bound to interactive functions, such as pause/play song, increase/decrease music volume,speed dial, and menu navigation.With the addition of a pico-projector to the armband, Skinput allows users to interact with a graphical user interface displayed directly on the skin. This enables several interaction modalities, including button-based hierarchical navigation, list-based sliding navigation (similar to an iPod/SmartPhone/MID), text/number entry (e.g., telephone number keypad), and gaming (e.g.,Tetris,Frogger).

EMBEDDED SYSTEMAnembedded systemis acomputersystemwith a dedicated function within a larger mechanical or electrical system, often withreal-time computingconstraints. It isembedded as part of a complete device often including hardware and mechanical parts. Embedded systems control many devices in common use today.Properties typical of embedded computers when compared with general-purpose ones are e.g. low power consumption, small size, rugged operating ranges and low per-unit cost. This comes at the price of limited processing resources, which make them significantly more difficult to program and to interface with.Modern embedded systems are often based onmicrocontrollers(i.e. CPUs with integrated memory or peripheral interfaces)but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also still common, especially in more complex systems. In either case, the processor(s) used may be types ranging from rather general purpose to very specialised in certain class of computations, or even custom designed for the application at hand. A common standard class of dedicated processors is thedigital signal processor(DSP).Comparison between microprocessor and microcontrollers:Microprocessor is an IC which has only the CPU inside them i.e. only the processing powers such as Intels Pentium 1,2,3,4, core 2 duo, i3, i5 etc. These microprocessors dont have RAM, ROM, and other peripheral on the chip. A system designer has to add them externally to make them functional. Application of microprocessor includes Desktop PCs, Laptops, notepads etc.But this is not the case with Microcontrollers. Microcontroller has a CPU, in addition with a fixed amount of RAM, ROM and other peripherals all embedded on a single chip. At times it is also termed as a mini computer or a computer on a single chip. Today different manufacturers produce microcontrollers with a wide range of features available in different versions. Some manufacturers are ATMEL, Microchip, TI, Freescale, Philips, Motorola etc.

Microcontrollers are designed to perform specific tasks. Specific means applications where the relationship of input and output is defined. Depending on the input, some processing needs to be done and output is delivered. For example, keyboards, mouse, washing machine, digicam, pendrive, remote, microwave, cars, bikes, telephone, mobiles, watches, etc. Since the applications are very specific, they need small resources like RAM, ROM, I/O ports etc and hence can be embedded on a single chip. This in turn reduces the size and the cost.Microprocessor find applications where tasks are unspecific like developing software, games, websites, photo editing, creating documents etc. In such cases the relationship between input and output is not defined. They need high amount of resources like RAM, ROM, I/O ports etc.The clock speed of the Microprocessor is quite high as compared to the microcontroller. Whereas the microcontrollers operate from a few MHz to 30 to 50 MHz, todays microprocessor operate above 1GHz as they perform complex tasks.Fields and Domains of Embedded Systems: Microprocessor Microcontroller Power Electronics Electrical System Digital Electronics Antenna and wave propagation-Wireless communication Transmission lines and waveguides-Wired communication Wireless sensorTypes of Microcontrollers:The major types of microcontrollers are: ATMEL PIC ARMATMELAtmel Corporationis an American-based designer and manufacturer ofsemiconductors, founded in 1984. The company focuses on embedded systems built aroundmicrocontrollers.It is a 4K ROM .ATMEL offers serial and parallel EEPROM, as well as one-time programmable (OTP) EPROM. In addition, it offers secure memory with its CryptoMemory product line of EEPROMS in capacities from 1 to 256kbits. And it uses only digital values.PICPIC- Pheripheral Interface Controller. PIC microcontrollers is a family of modified Harvard architechture microcontrollers made by Microchip Technology, derived from the PIC1650. It uses 8K ROM.. Its capacity is 256 bits. It uses both analog and digital values.ARMArm is a family of instruction set architectures for computer processors.. It is a 32 bit controller.Pin description of ATMEL(AT89C51):VCCPositive (+ve) Dc Supply voltage. Which is normally between 3V to 5V Dc.

GND0v Ground. This pin is connected to -ve dc supply voltage.

PORTSPorts are generally used by computers to communicate to the outside world. Microcontrollers use port to read input from another device or to send output to another device. AT89C51 has four ports for communication. Port 0, Port 1, Port 2, Port 3. These ports are 8-bits bi-directional i/o ports. They can be used for both inout and output ports. As an output port, they can sink eight TTL inputs. Ports can be used as an input when they are made to read data from another device(which can be a component or a sensor). Or as an output when they are used to send a signal to another device.RSTReset input. This pin is used to reset the microcontroller. If a high remains on this pin for more than two machine cycle while the oscillator is running, the microcontroller is reseted.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address durong access to external memory. This pin also the program pulse input (PROG) during Flash programming. This pin used to program the microcontroller.PSENProgram Store Enable is the strobe to external program memory. When the AT89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.PinofAT89C51Pin diagram of AT89C51 microcontroller

XTAL1Input to the inverting oscillator amplifier and input to theinternal clock operating circuit. This pin is connected to the external crystal oscillator together withXTAL2.XTAL2Output from the inverting oscillator amplifier.EA/VPPExternal Access Enable. EA must be strapped to GND inorder to enable the devicetofetch code from external programmemory locations starting at 0000H up to FFFFH.EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage(VPP) during Flash programming, for parts that require 12-volt VPP.SERIAL COMMUNICATIONSerial communication is used for all long-haul communication and mostcomputer networks, where the cost ofcableandsynchronizationdifficulties make parallel communication impractical. Serial computer buses are becoming more common even at shorter distances, as improvedsignal integrityand transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, orSerDes) and to outstrip its disadvantages (clock skew, interconnect density).The term "serial" most often refers to the RS232 port on the back of the originalIBM PC, often called "the"serial port, and "the"serial cabledesigned to plug into it, and the many devices designed to be compatible with it.Types of connectors: 9 pin connectors 25 pin connectorsIncomputing, aserial portis aserial communicationphysical interface through which information transfers in or out onebitat a time (in contrast to aparallel port). Throughout most of the history ofpersonal computers, data was transferred through serial ports to devices such as modems,terminalsand various peripherals.

Pair offemaleMini DIN-8connectors used forRS-422serial ports on aMacintosh LCcomputerWhile such interfaces asEthernet,FireWire, andUSBall send data as a serialstream, the term "serial port" usually identifies hardware more or less compliant to theRS-232standard, intended to interface with amodemor with a similar communication device.Modern computers without serial ports may require serial-to-USB converters to allow compatibility with RS 232 serial devices. Serial ports are still used in applications such as industrial automation systems, scientific instruments,point of salesystems and some industrial and consumer products.Servercomputers may use a serial port as a control console for diagnostics. Network equipment (such as routers and switches) often use serial console for configuration. Serial ports are still used in these areas as they are simple, cheap and their console functions are highly standardized and widespread. A serial port requires very little supporting software from the host system.The individual signals on a serial port are unidirectional and when connecting two devices the outputs of one device must be connected to the inputs of the other. Devices are divided into two categories "data terminal equipment" (DTE) and "data circuit-terminating equipment" (DCE). A line that is an output on a DTE device is an input on a DCE device and vice-versa so a DCE device can be connected to a DTE device with a straight wired cable. Conventionally, computers and terminals are DTE while modems and peripherals are DCE.If it is necessary to connect two DTE devices (or two DCE devices but that is more unusual) a cross-overnull modem, in the form of either an adapter or a cable, must be used.Applications of serial ports: Dial-upmodems Bar code scannersand otherpoint of saledevices LEDandLCDtext displays,Printers,Computer terminal,teletype,Olderdigital cameras Satellite phones, low-speed satellite modems and other satellite based transceiverREFERENCES1. http://en.wikipedia.org/wiki/2G2. http://en.wikipedia.org/wiki/RJ453. http://en.wikipedia.org/wiki/Skinput4. http://en.wikipedia.org/wiki/Skinput5. http://en.wikipedia.org/wiki/Embedded_system6. www.dauniv.ac.in/downloads/EmbysyRevEd7. www.engineersgarage.com8. www.wikipidea.en/wifi/history9. www.osimodel.org10. http://www.bing.com/search?q=data+security+assessment&form=IE10TR&src=IE10TR&pc=HPNTDFJS

3