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Principles of Modern Communication
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Principles of Modern Communications
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Receiving Device
Simplex Mode
Half-Duplex Mode
Full-Duplex Mode
The transmission mode is the process of transerring data and information between two devices. There are three types of transmission modes.
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SEND
Transmission Modes
RECEIVE
Simplex Transmission is unidirectional communication--meaning it’s one-way only. Out of the two connecting devices, only one is capable of transmission and the other one is only capable of receiving. Traditional monitors and keyboards use simplex transmission method. The monitor can only generate the output, and the keyboard can only introduce input into the system.
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HELLO
Transmitting Device
Half Duplex transmission is when every station can both receive and transmit data, but not at the same time. When one of the devices sends information, the other one can only receive it. Half-duplex mode comes into play when two way simultaneous communications is NOT required.Walkie talkies are an example of half-duplex communications.
only one direction
Where are you?
Full-Duplex communication can transmit and receive data simultaneously. There is a communication channel that can transmit and received in both directions. Phone networks establish communication between individuals using Full-Duplex. Individuals can listen as well as talk at the very same time.
only one direction at a time
two directions at the same time
Protocol: The set of rules governing the format, timing, and sequencing of data transmission.
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Sender: The device that starts the transmission of data
Receiver: The device that receives the data sent
Elements of Modern Communications
Message or data: The information transmitted from one device to another, including text, images,audio, video, or any other form of content
Good morning, Joe. Can you send me the account number to complete the purchase?
Data transmission is sending and receiving digital or analog data between devices. This can be achieved through different mediums, such as cables, optical fibers, or wireless signals. Data transmission is essential in the modern economy. It is essential to understand the basic principles of modern data communications in order to maintain and secure these communication systems.
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Medium: The physical path or channel through which data is transmitted such as a fiber cable or a wireless signal
Social Engineering
Scareware Ransomware
How to Mitigate Attacks
Dumpster Diving
Phishing
Introduction
Baiting
Spear Fishing/Whaling
Tailgating
Pretexting
Conclusion
Social Engineering Attacks On the Rise
Shoulder Surfing
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Network Topologies
B U S
There are six types of network topologies. The logical topology is the way network devices are connected on the network to one another. These topologies include bus, ring, star, mesh, tree or hierarchical and extended star.Networks can also have a logical topology that can be different from the physical topology.
The bus topology uses a single media to connect multiple devices. Each device has a physical mechanism to "bite into" or connect to the media. This was one of more popular topologies, but it has become obsolete.
Devices connect in a circular manner and form a closed loop. Each device is connected to exactly two other devices that creates the pathway for data transmission.
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R  I N G
S T A R
All devices or nodes are physically connected to a central node such as a router or a hub. In its simplest form, this central hub is the middleman and transmits all messages.
E X T E N D E D
End devices connect to a central intermediate device, which in turn connects to other central intermediate devices such as a switch.
When there is a single source for data, and the data has to be distrubuted among nodes, use the heirarchical, or tree, topology.
H E I R A R C H I C A L
M E S H
Devices are interconnected in a decentralized manner. Each device connects directly to multiple other devices instead of relying on a central hub or switch.
TDM uses a physical or electronic switch to connect two devices. TDMs enable multiple devices to communicate across one carrier media. Each sending device is allotted a specific amount of time to transmit or receive across the shared media. The receiving devices are also able to share a single media channel to receive transmitted information
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Signal Multiplexing
Refers to a method of transmitting data to all the devices on the same network. In other words, it is a one-to-all communication method. Excessive use of broadcasting can result in generating too much network traffic. Many popular network protocols or services use broadcasting. This includes DHCP, DNS, ICMP and many others.
Broadcast
Refers to a one-to-one communication method. This model sends data from one device to another using a specific IP address. In other words, a single sender transmits packets to a single receiver. Unicast is the most common form of data transmission used in computer networks. It is an efficient method to transfer data from other networks to a specific device.
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Modern communications use three different methods to send information on a network.  These methods are called unicast, multicast and broadcast. 
Data Transmission Methods
Unicast
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Multicast
Multicasting refers to a transmission mode that allows one stations to send video streams or data to multiple devices. Multicast traffic is transmitted to a multicast group of devices. All the multicast devices must share the same multicast address. Multicast transmissions transmit data one time to multiple devices. This type of transmission is needed to send a live or recorded video to many devices at the same time. Mulicasting is also used to send a workstaion image to multiple devices when re-imaging workstations which can save time and bandwidth.
Both baseband and broadband describe how data is transmitted across network media. Baseband technology refers to the transmission of all information across the media using one frequency range. Broadband uses multiple frequency channels.
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Voice
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Data
Base
Consider baseband as a railway track--only one train can travel on the track at a time. If multiple devices need the media to communicate, the information must be sequencially connected and transmitted down the media channel. Therefore, this system can transmit only one signal or one channel in one direction at any time. An ethernet network utilizes baseband.
Broad
Baseband Versus Broadband
Broadband is like a highway with multiple lanes. Cars can use the right lane if travelling slower, while the faster traffic uses the left lane. Cars only travel in one direction. Broadband is a transmission technoogy in which many signals with different frequencies send data across a single channel at the same time. The signal travels in only one direction per channel. A cable subscription service utilizes broadband.
Baseband
Broadband
Ethernet Frame Format
Sender
SFD 1 Byte
Length 2 Bytes
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Synchronous Communications
Receiver
Synchronous transmission is a method of data transfer where data is sent in a continuous stream called a frame or packet. This method requires that both the sender and receiver commuication channels are synchronized. The sending station sends a preamble to synchronize the clockrates. Synchronous transmission is highly efficient for transmitting large volumes of data over high-speed networks, as it minimizes the overhead required for data framing and error checking. It is commonly used in scenarios where speed and efficiency are critical, such as in server-to-server communication or high-speed data acquisition systems.
Destination  Address 6 Bytes
CRC 4 Bytes
Preamble 7 Bytes
Data 46-1500 Bytes
Source Address 6 Bytes
Time-Division Multiplexers (TDMs)
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Frequency-Division Multiplexers (FDMs)
A multiplexer allows multiple devices to communicate across a single media channel. Multiplexers process multiple inputs and create a single output that can be transmitted. A multiplexer on the other end separates each individual host communication signal and delivers it to the device.
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FDM enables multiple devices to share a single transmission media. However, FDM constantly transmits information across the share media using different frequency ranges. The receiving device tunes in the specific frequency that is being used to carry information and blocks out all other frequencies. Cable TV services use this method to carry hundreds of different channels.
Synchronous Communication
Asynchronous Communication
In the realm of digital communications, the methods by which data is transmitted from one point to another are crucial for the efficiency and reliability of information exchange. Two fundamental approaches to data transmission are synchronous and asynchronous transmission, each with its unique characteristics, advantages, and applications. Understanding the differences between these two methods is essential for anyone involved in the design, implementation, or use of communication systems.
Synchronous/Asynchronous Communications
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Stop bit
0
Asynchronous transmission does not rely on a shared clock signal between the sender and receiver. Instead, data is sent in individual packets or characters, each framed with start and stop bits to signal the beginning and end of the transmission. This method allows for data to be transmitted at irregular intervals, making it ideal for scenarios where data is generated sporadically or at varying speeds. Asynchronous transmission is widely used in serial communication, such as in computer keyboards, mice, and many types of point-to-point communication links.
11110001
11111011
Gaps between data units
10011011
Start bit
Analog Signals
Analog signals are continuous signals that vary over time. They can take on any value within a given range and are used to represent sound, light, temperature, or pressure. When speaking into a microphone, the sound waves (analog signals) are continuous, reflecting the subtle changes in air pressure caused by your voice.
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Analog and digital signals are two fundamental types of signals used in electronic systems to represent information. The primary difference between them lies in how they represent data and their susceptibility to noise and degradation. The Digital Modulation Emate has additional information.
Digital Signals
Digital signals represent data in discrete steps or levels. They encode information as a series of ones and zeros (binary code), each bit representing a state (on or off, high or low). This binary representation makes digital signals less susceptible to noise and degradation compared to analog signals.
Analog Versus Digital
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