TYPE DATA TRANSMISSION

Data transmission can be divided into two kinds, serial transmission and parallel transmission. Serial transmission is the transmission of data where in one time unit only one bit is transmitted, thus the data consists of many bits, sent in her order, one by one. Each computer is equipped with a serial channel or serial-port (RS-232C), the channel that can receive / send data serially. Parallel transmission is the transmission of data where in one unit a few bits (usually 8-bit) can be routed simultaneously. On computers are also available from the channel-parallel or parallel port as a channel which is connected to the printer when it prints the data.In fact, long-distance communication via serial cable a lot done, as telephone lines, due to parallel transmission cables required 8-fold in serial transmission cable needs.Configuring Communication PathConfiguring the communication path is a way to connect peripheral devices that will communicate, can be divided into: configuration point-to-point (point-to-point) and multi-point configurations (multipoint).Point-to-point (point-to-point) specifically connects the two devices want to communicate. This configuration is found in many parallel transmission, such as communication between two computers in parallel to do the copying of data files, although the serial transmission is also possible if the distance between two remote devices.
 IMAGES: Connection Point-to-PointMulti-point (multipoint) suggests a relationship that allows a pathway used by many tools to communicate. An example is the configuration on the network bertopologi bus, where one data channel (backbone) connected to multiple computers.
 IMAGES: Multipoint ConnectionTransmission ModeTransmission mode is a way of sending data from one device to another device, that is in sync (synchronous transmission) and non-synchronous (asynchronous transmission).Synchronous transmission is the transmission of data where both parties, sender and receiver, are at the synchronous time, usually begins with a SYN signal to synchronize between the two devices are communicating, then follow the signal STX (start-of-text) that states the beginning of data transmission , then a number of (block) of data sent, and closed with the ETX (end-of-text), last no signal BCC (block-check character) that is used to check for errors in data reception.Transmission is a non-synchronous data transmission in which both parties, the sender and receiver do not need to be in time sync. Transmission mode is applied to the data communication device in which the speed of sending and receiving devices is much different. As an example of data transmission from the keyboard to be non-synchronous memory for keyboard speed is determined by the speed of the user in pressing the (human factors), memory speed is determined by the transfer-rate of memory, however the man in typing speed is still slower than the processor speed in transferring the data. If done in a synchronized manner the memory / processor is a lot to lose time in vain, waiting for a keypress. Non-synchronous transmission usually be done character-by-character, where each character at the beginning of the start-of-bits (SOB) and closed with a parity-bit (to check for errors) and end-of-bits (EOB).Direction of TransmissionTransmission direction of the two devices that communicate can be divided into three kinds, namely: Simplex, Half-duplex, and full-duplex.Simplex communication states between the two devices can only be done in one direction only, from the source / sender to the recipient / recipients. As an example of communication between the transmitter TV with TV sets, communication between the amplifier with the speakers, the communication between the barcode device with a computer.Half-duplex communication between two devices states that can be done both ways but not simultaneously (not together) but alternately, when one device is sending the other only receives, and vice versa. As an example of communication using the Handy-Talkie-Talkie or Walki done in half-duplex.Full-duplex communication between two devices states that can be done both ways and can be simultaneous (concurrent). As an example of communication via the telephone is a full-duplex communication.Communication between two computers could use one of the three-way transmission, depending on the communication protocol it uses.MultiplexingMultiplexing associated with the effectiveness of use of communication media, which one would be more effective if the media can be used by more than one data transmission. For example, a medium that has a large capacity (eg fiber-optic to 384 Kbps) certainly is not efficient when used by only one low-speed transmission (eg connect two computers with 64 Kbps). Devices necessary to perform multiplexing is a multiplexer (MUX) and demultiplexer (demux).
 IMAGES: MultiplexingThere are basically three kinds of multiplexing, namely: Time Division Multiplexing (TDM), Frequency Division Multiplexing and Code Division Multiplexing (CDM).TDM (Time Division Multiplexing) is a multiplexing technique by giving time allocated to each transmitting in turn. TDM technique commonly used when the total transmission capacity exceeds the capacity of the medium, the so-called baseband medium (narrow lane). Because the medium capacity is limited so any device that communicates gets-time slot to send data.
 IMAGES: Time Division Multiplexing, Channel Gets Every Time AllocationFDM (Frequency Division Multiplexing) is a multiplexing technique in which each device was given a different modulation frequency so that it can simultaneously transmit over a single medium. FDM techniques are widely used in data communication with a large-capacity medium, commonly referred to as broadband (broadband) medium. Through this technique a variety of TV broadcasts can be transmitted in one cable (cable TV), or video, audio, and data can be routed together in one cable.
 IMAGES: Frequency Division Multiplexing, each channel using different frequenciesCDM is a multiplexing technique in which each channel or devices that communicate using different data code so that it can simultaneously (as in FDM) at one time, and also can use different time slots (as in TDM). CDM technique allows voice communication channel bandwidth can be shared by many cellular phones.
  Untiran cable.Cables of this type is the most widely used cable as used for telephone networks. This cable is made of copper where multiple pairs of wires in-untir and rolled into one. To enhance the quality of the cable, each pair of wires going frequently to each other in so-called cable untir untir's.

 Coaxial CableIn this type, the main cables made of copper will be surrounded by a finely woven copper wire and other insulating them there. From the point of price, this cable is more expensive when compared with cable untiran, but given the quality is also better.Fiber Optic Cable (Fiber Optics).Currently there are efforts to use light as a medium of communication. Existing data will be taken by the light, and to channel the light that carries the data, required the presence of a specific type of cable, and cable is called a fiber optic cable or fiber. Fiber optic cables consist of a glass fiber is very thin and can be used to distribute data in number and very high speed.Radio waves, AMShaped analog signals, can also be transmitted through air, such as: radio waves. AM-Radio, which stands for Amplitude Modulation, can capture the signals at the same frequency, and amplitude and the strength it has, it can be moved towards the intended information.Transmitter-FM Radio / Television StationFM transmitter and radio-television station can also be used to channel analog waves. In this case, television station or radio transmitter-FM (Frequency Modulation) will inhabit the waves between 54 ng to 806 megahertz (Millions of cycles per second)Short Wave Radio Communications.In this case, shortwave radios are widely used by certain circles, for example ORARI or police, can also be used to carry analog signals to the place of destination. Short-wave radio communications have a higher frequency when compared with the frequency of which is owned by pemacar-AM radio.Cellular TelephoneCeluler telephone or cellular phone, car phone or working at 825 to 890 megahertz frequency, can also be used as a data communications transmission medium.Micro wave.Data communication via the electro magnetic waves (air) is the most widely used by microwaves or microwave. This method can reach great distances, so many industries that use it for personal or move / distribute voice, video or data communicationsSatellite.The use of satellites designed to reduce shipping costs on very long distances. When used microwaves, it would require a lot of earth station transmitters to be built. Besides, it also must keep in mind the existence of ocean that separates the mainland from one another. By using satellites, then the existing problems can be overcome. Satellites are generally working at a frequency between two to 40 gigahertz (billion of hertz)