CompTia A+ Training - Looking at Networks

Knowing about networks is vital to a role as computer technician. In the A+ certification, module six you explore what networks are and how they work through a series of knowledge and practical based questions, enabling you to handle the practical and theoretical side of I.T.

For starters, module 6 of the A+ certification explores what exactly a network is. A network is a collection of computers or devices that are connected together in order to cross communicate with one another. It allows various users to exchange information between one another from one computer to another. They are various network types, including WANS (wide area network), LANS (local area network), HANS (home area network), PANS (personal area network) and the intranet (a set of networks using internet protocol) etc. There are various methods to connect as well, including wired and wireless methods, which can connect up as little as two devices up to hundreds.

You will also need to know the hardware required for a network. Some basic structural components do remain the same on any network, whilst other hardware components vary from network type to network type. Here's a few of the hardware components, you will need to get acquainted with as an I.T technician.

Network Interface Cards: Or NICs as they are also known. NICS, network adapters or network cards are a type of hardware that allows computers to communicate over a computer network. Without this connection medium, you would not be able to access the computer network through your computer.

Hubs: You've probably come across one of these at some point. The hub (Ethernet hub, active hub, network hub etc) is simply a device that connects multiple Twisted Pair (the copper wire for Ethernet) or fiber optic Ethernet devices together. Once data is received to one port, it is passed on to the other ports without regulation.

Repeaters: Let's say there's an obstruction in your networks way - well a Repeater is the device used to solve this problem. by receiving and strengthening a signal (analogue and digital) and then retransmitting it, the signal can reach further, as well as overcome any obstacles in its path.

Network Bridges: Similar to Repeaters and Hubs, but ever so slightly different as a Network Bridge not only connects at the physical level of the OSI model (Open Systems Interconnection model), but the second layer too. This first level, without the overlay of computer jargon, specifies the relationship between the transmission medium (i.e. copper wires, fiber optics) and device, whilst layer two is the data link layer which allows transference of data between network entities and corrects any mishaps in the first layer.

A Network Bridge is far more complex than a hub, as it makes connections between the port and network address, allowing traffic to reach that port only. A hub instead relays all the data to all the ports, often causing collisions and slowing down traffic. A Network Bridge, unlike the Hub which does not recognise the data source, where it is going and what the data means, instead manages the data before it decides to send it to another network segment.

RS-485 Converter - A flexible multi-point networks standards

For many people today term "network" is more than just connect their wireless access point and to ensure that the office can access the Internet, and perhaps files on other computers at home o. The conditions of RS232, RS422 or RS485 little to say today's consumers who are used to USB Plug and Play, and perhaps an Ethernet cable for connection to a reliable high-speed router. However, allowing the world to the mass market consumer electronics, and RS-485 is astandard network important for industrial applications and techniques, such as device control, data acquisition, remote device management and so on. So let's re RS-485, what is and what it can do.

First, unlike the standard RS232, RS485 is not possible, a protocol or data-out pin. Instead, it describes the electrical characteristics of drivers and receivers in digital systems.

Like the RS-422 ports, RS-485 systems use "balanced" signalspositive and negative voltages (in the range of -6 to +6 V) on twisted pair cables. This makes them much more immune to interference as "deranged" RS232 signals and also allows speeds of up to 10 Mbps over short distances is a maximum connection distance of 4,000 meters at low speed.

However, while RS-422 is limited to a single driver, with up to ten knots or receiver, RS-485 is a true multi-point with a maximum of 32 drivers and 32 receivers. This means thatthat up to 32 riders can communicate through the same pair of wires. What if 32 is not sufficient for a question? Then, a repeater allows you to add a further 32nd If this is not enough, additional repeater has up to the guideline system, which is usually 256 units.

As far as connections go, the RS-485 standard is not set, a certain kind of result you can use standard DB25 or DB9 serial ports, but also to RJ11 or RJ45, a terminal strip,or a variety of DIN connectors. Connect to any computer via standard RS232 port requires an interface card or RS485 or RS232 to RS485 converter. In commercial and industrial classes are of high quality. When an impulse, ground loops and transient pulses are a problem, look for a drive opto-isolated to protect your computer.

Note that the network configuration or 485-2-wire or 4 wire. drivers are 2-wire system and receivers connected on a singlea pair (plus a special signal ground). The nodes can communicate, but communication is only half-duplex. In a 4-wire (plus ground), a driver for all channels of the node is connected to a pair of receivers and transmitters of the nodes are connected to the receiver on a second driver torque. This allows full duplex communication, but also the central nodes can not communicate directly. Each system has its benefits and uses.

Since485 or, as they are called correctly, EIA-485 signals are not limited to a certain standard, can be used in a wide range of control and automation. Add the minimum wiring and high resistance to electromagnetic interference and you have a standard that could be important in coming years.

Networks

Networking of computers is not only the connection of individual computers, but also digital devices for data transfer. These devices, but with the difference in technologies used by different networks. But network equipment can be used as interface cards (NICs), bridges, hubs, switches and routers. Next to them, an Ethernet card are required. The common methods of connection you are using Category 5 cables, fiber optic cables. Sometimes radio (IEEE 802.12)is also used to connect these structures.

NIC

A network card, network adapter or network interface card (NIC) is a hardware that will communicate with computers on a network of computer help. Physical access to a support network is equipped with this device. Often a low-level addressing system is also supplied with the device through the use of MAC addresses. Relay

A repeater is only because of its ability to clean the noisesignal reception. This electronic device regenerates and the noise-free signal transfer with a higher power, relieve the obstruction. Sun signal spread over long distances without loss of quality. Repeaters are required for cables longer than 100 meters in most of the twisted-pair Ethernet configurations.

Hub

The network hub with multiple ports, package arrived in a port, then copied to all ports hubTransmission without any modification. The destination address in the frame is not changed in a broadcast address.

Bridges

Network Bridge connect multiple network segments. These plants never sent to different ports on the receipt of shipment. However, do not copy bridges traffic on all ports, but to identify the MAC addresses reachable through specific ports.

Switch

switch block filter data between ports according to theMAC addresses in packets. In contrast, connected to a hub, only the frames are transmitted to the communication ports rather than all the ports involved. A switch to interrupt the collision domain, but is itself a broadcast domain. Switch decide the forwarding of frames with respect to their MAC addresses. Each switch has many ports in general. It helps to promote a star topology for the devices on the network and cascade additional switch. Some switches are capable ofRouting.

Router

Routers are network devices that route packets between networks. Packet transmission depends on the information in the protocol headers and forwarding tables a. These two determine the best next router for each packet.

Wireless networks - has rapidly become the standard configuration

Wireless networks have become incredibly popular - so much so that virtually all new laptops have wireless cards, as part of a set of standard features. Indeed, customers with the seller strange, blank look, as if the wireless networks is one of the features included as standard. People love the convenience of being able to boot your laptop and surf wherever they are.

Wireless networkshas become so popular and convenient that many people choose now, this convenience in their homes, too. If you happen to your home to one of thousands of people in networks, installation, select wireless, then it is for a couple of things you must work to understand networks, such as wireless.

One of the most interesting and the best properties of wireless networks is that they are wireless. This makes installation easyand allows you the freedom to move into the home can work with your laptop. redundant networks, wireless networks are the wires associated with traditional Ethernet.

The installation of wireless networks at home is fairly painless. Moreover, compared to traditional cable or an Ethernet network, it is relatively inexpensive. Many times, you can create a wireless network at home for less than one hundred dollars. The only drawbackwireless networks is that they are a bit 'slower than Ethernet. However, the average consumer will not notice the difference either.

Most wireless networking technology for home to work on this technology called 802.11g. This means that the data is sent over the network at 2.4 GHz transmitted at a rate of 54 megabits. For non-technical people, it means that the data fast enough. new technology is currently in production forwireless networking (802.11n), but is still in beta, or test phase.

Wireless networks operate, either through the modulation of radio waves or infrared light pulses. This includes a router that is connected to your Internet connection and transmits data via radio or light waves. The computer receives the wireless adapter is an external or internal, the receiver behaves as above.

When you install a wireless thoughtHome network, you need a high-speed Internet connection, wireless router and adapter for each computer you want to access the network. Most wireless routers have only a basic range of about 100 meters, so if you live in a bigger house, you may need to buy a range extender or repeater for the network. And that's pretty much it.

Wireless networks are easy to install and affordable. If you have not already decided to bite the bulletand install in your home, you're not. Installation takes only a few simple instructions and reading. Do so and enjoy a wireless network that the whole family.