Characteristics of a Data Communications System

The use of data communications systems are becoming increasingly prevalent these days because of the rapidly changing way in which we do work, communicate or entertain ourselves. We use computers for most purposes these days, but are never satisfied with the available technology. One of the fastest changing fields we have today is communications, and most of the developments in information technology are therefore directly concerned with this field.

There are many ways in which data can be exchanged between two computers. The wide variety of transmission mediums available ensure that data can be exchanged with ever increasing ease. These mediums include satellites and microwaves in addition to the regular wire cable systems.

Every data communications system requires a few characteristics in order for it to be successful. The first of these characteristics is that the data should have a well defined origin and destination so that it reaches the place it is intended for. Therefore, the transmission should only be from a source device to a destination device without any interference from any other devices.

The system will be successful only if the data is delivered in an accurate manner. In fact, this is of the utmost importance. The system will need to retransmit the data if any error occurs during the process of initial transmission. Needless to say, the best systems are those that have the least errors.

The time taken to transmit data is also very relevant. The system needs to offer real-time transmission of data. This is of special importance in real time systems because the data is redundant if it delivered after a delay. These points need to be kept in mind while evaluating the effectiveness of systems for data communications. The end result is the transmission of data in a timely and reliable manner while being very cost effective.

Basics of Data Communication

By the help of direct, two-level electrical signals over simple copper conductors, the digital data can be transmitted. These types of transmission are needed as the distance over which data moves within a computer may vary from a few thousandths of an inch. In this case within a single IC chip, to as much as several feet along the backplane of the main circuit board, the help of copper conductors are utilized. The circuit designers are not concerned about the shape of the conductor or the analog characteristics of signal transmission except for the fastest computers.

The data should be sent beyond the local circuitry that constitutes a computer. The distances involved may be enormous in many applications. As the distance between the source of a message and its destination increases, efficient transmission of data becomes increasingly difficult. This is mainly due to the electrical distortion of signals occurs while traveling through long conductors and from noise added to the signal as it propagates through a transmission medium, which is generally called as the Channel in a communication network. The biggest challenge occurs when the data is transferred to devices outside the computer’s circuitry. In such applications, the distortion and noise influenced through the channel can become so severe that information may be lost.

The transmission of digital messages to devices external to the message source, Data Communications is mainly concerns. The maximum permissible transmission rate of a message is directly proportional to the signal power and is inversely proportional to channel noise. The aim of any communications system is to provide the highest possible transmission rate at the lowest possible power and with the least possible noise. In other words, the task of a communication is to increase the data (signal) strength and to minimize the noise content. This can be represented by the Signal to Noise ratio (SNR). The aim of any communication network should be to maximize the SNR strength. Here Maximizing the SNR will leads to the minimization of the noise content.

Serial Communications:

Most digital messages are greatly longer than just a few bits. Since it is neither practical nor financial to exchange all bits of a long data at the same time, the data is broken into smaller parts and passed on sequentially. Bit-serial transmitting provides a one bit data at some point through a route in transmitter-receiver link. Each bit symbolizes a part of the data. The individual pieces are then put back together at the destination to restore the data. In general, one route will pass only one bit at some point. Bit-serial transmitting is usually called serial transmitting and is the most chosen transmission method in many computer peripheral devices.

The byte-serial transmitting provides eight pieces at some point through eight similar channels. Although the raw exchange rate is eight periods faster than in bit-serial transmitting, eight channels are needed, and the cost may be as much as eight periods higher to deliver the data. When ranges are short, it may however be both feasible and financial to use similar programs in return for high information rates. The popular Getronics printer interface is a case where byte-serial transmitting is used. As another example, it is common practice to use a 16-bit-wide information bus to exchange information between a micro-processor and memory chips; this provides the equivalent of 16 similar programs. On the other hand, when interacting with a time period discussing system over a computer, only one route is available, and bit-serial transmitting is required.

Different Types Of Data Communication Media

The process in which data is transferred from one computer to another is known as communication media. Data communication involves transmission of digital of information to different electronic devices through wireless or cabled connections. The two commonly used computer communication media used are bounded and unbounded media.

A. Bound Media

Data transfer through physical connections is referred to as bounded media in that signals are sent to other external devices from one computer in a network. Computers can be interconnected to share files and devices in a network by means of cabling which facilitates faster communication of information. Bounded media is a faster data communication that provides high speed transfer of signals over long distances and is the most reliable media for message sending.

Bounded media is categorized into three types of data communication which enables connection of different types of network. These cables include:

1. Coaxial cable

This is most common bounded media that is many electronics to transfer data and it is designed with two parallel copper conductors. It has a solid central copper conductor that transmits signal and is coated with a protective cover to reduce electromagnetic interference. Coaxial cable is found in different gauges at affordable prices and is easier to work with. They are easy to install and can support up to 10Mps capacity with medium attenuation. Despite its popularity, the only serious drawback it has is that the entire network is always affected with a single cable failure.

2. Twisted pair cable

Twisted pair cables are found in two types and these include unshielded and shielded twisted pair cables. It is commonly used because it is lighter and inexpensive. They are made up of twisted solid copper wires which help to reduce vulnerability to EMI and cross talk effects. This type of cables is cheaper and can support up to 100mps speed capacity.

3. Fiber optic

Unlike other types of cables, fiber optic uses electrical signals for communication and is made up of reflective cladding that prevents loss of light in the glass core. Although it very expensive and hard to install, optic cables can support at least 2gbps and are not vulnerable to EMI interference. It has got also very fast data transmission and very low attenuation compared to other data cables.

B. Unbounded media

This type of data communication media involves networking of multiple computers through a wireless connection. Creating a wireless connection is much easier since no physical connection is required and can connect multiple computers in a room. Unbounded media uses space or air as the transmission medium for electronic waves. Some of the unbounded media are the satellites, radio, Bluetooth and Wi-Fi among others. Installation of wireless network is much easier and faster compared to the bounded media which require an expert to do the configuration. Through wireless settings, you can also transfer huge files of data to any networked computer since the unbounded media supports very high bandwidths just like the cabled network.

Generally, in order to transmit data over networked computers, you will have to use either bounded or unbounded types of media. Depending on the type of network you want to create, convenient type of media is required to enable consisted and proper data communication.

The Basics Of Mobile Data Communications

Most people today are familiar with data plans on cell phone systems. It allows them to access their email and the internet from their cell phones. However, most people are not familiar with mobile data communications. This is something that, while similar to the aforementioned cellular plans, is actually used to transmit user to user information.

Commonly used by emergency personnel, mobile data communications allow police, fire, and EMTs to transmit and receive critical information in the form of data. Some might wonder why this method is preferred to traditional radio communications, and the question is well asked and answered.

In the military, radio personnel are trained in communications techniques to keep confusion to a minimum. Because certain letters have a similar sounds when spoken and can be easily confused with another, a system was needed to help reduce this problem to a minimum. Letters like T and P have a similar sound, so instead of simply saying T or P, they would say a word that began with the appropriate letter. T was now Tango and P was now Papa.

This ability to keep confusion to a minimum was further reinforced by standardized training and consistent use of these words representing letters. However, while this greatly reduced misunderstanding, it did not eliminate communication errors. Today, it is necessary to be able to communicate much more specific and lengthy information in certain emergency situations; therefore, a new system was needed.

The easiest solution would be to transmit the raw data from one point to another. This would allow the end user or recipient the ability to receive accurate information without the possibility of transmission error. The other benefit of this type of mobile data communication is that it helped keep information more secure than it would be if transmitted over open airwaves where anyone could be listening.

The secure aspects of this kind of site to site com appealed to the military, the police, and other public servants engaged in emergency response. In the case of medical information and the requisite security concerns, raw data transmission seems the best option available.

Until recent years, this type of transmission required high specialized equipment and was very cost prohibitive. The other draw back was the speed of the transmission. In the early days, it might take just as long to transfer the data to the end user who needed it, as it would be to relay it via voice transmission. Today, with the technological advancements that have been made, mobile data transmission has never been more secure and quick.

There are specific companies that specialize in mobile data transmission. While one would think that cellular companies would be leading the pack, the security requirements and technology while similar are very different. This means that specialized equipment is still a necessity although not quite as cost prohibitive as years past.

The sheer numbers of emergency responders has increased as the population has increased. This means that proprietary systems are necessary to keep information from becoming confused with multiple transmissions.

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