Introduction to Telcommunication Cable

Here you will learn about submarine communication cable, amplifiers, repeaters, fiber optics ,telecommunicaion network and fiber optic cable companies. Submarine communication cables are the fiber optical cables and are used for the cross Atlantic communications. Submarine cables are consisting of fiber optics and electrical conductive tube that is used to transfer the electrical signals between the repeaters. Repeaters are the network communication and telecommunication devices that are used to amplify the signals.  

Repeaters operate at the physical layer of the OSI layers model and work with the physical signals. Submarine fiber optical cables are less susceptible to failure and are very high transmission cables. Submarine fiber optical cables are usually laid 1m under the sea. A great research and planning is required to install the submarine fiber optic cables. Fiber optic cable is a light weight cable, 13 cm in diameter and consists of a bunch of glass fibers that are cable of transmitting the light. So the data is transferred at the speed of light through the fiber optic cables. Normally the submarine cables are not installed on the area where the fishing and ship activities are more.

Because ship anchor and shipping vessels can be the problem for the submarine cables. Submarine telecommunication cable is a cable that is used for the telecommunication between the countries across the world. With the passage of time, the submarine cables have advancements and new technologies and communication devices are being used in the telecommunication. Submarine telecommunication cables with the high amplifier can transmit data and signals at more than 5 GB per seconds. Submarine cables were first used for the telegraphic transmission between the countries, then for telephone and then for data communication.

Today, fiber optic submarine cable is the backbone of the whole internet. In case of any damage to the submarine cables the whole communication system can be greatly affected. The international cable protection committee was established in 1958 in London to protect the submarine cables.

This committee is funded by the member fiber optic cable operators and the main responsibilities of this committee to protect the submarine communication cable. Earlier telecommunication submarine cables were not using repeaters so there were great bandwidth problems. In 1980 fiber optical was developed it uses the optical amplifiers to transmit the signals at a very high speed. Submarine power cables are running for supplying the electrical power. Fishing, anchoring and shark fish bites can cause the damage to the cables and the damaged portion of the cable is brought to the surface for repairing purposes. The installation and the repairing cost of the submarine cables is very high. These cables are laid in the seabed by the cable lying ships. These ships are owned and operated by the wireless and big telecommunication companies around the world. The optical fibers in the fiber optic are used as a sensor to measure heat, pressure and temperature.

Fibers are made up of transparent plastic and glass to pass the light at a very high speed. Earthquakes are also the cause of the damage for the communication cables and a major Tsunami earthquake in December 2004, in the Indian Ocean caused big damages to the underlying telecommunication cables. Telecommunication cables have a large network across the world. Some of the major submarine cable companies of the world are Apollo, Pan American Crossing, Pacific Rim East, Japan-US, Columbus II, Columbus III, RJK, Eastern Caribbean fiber system and many other companies.

Introduction to Laser Printer

Laser printer is a common type of the printing system that uses laser beam to produce the high quality text and images on the photosensitive drum. The images are then transferred to the paper by xerographic printing system. Laser printers are sometime called page printers because the entire pages are transmitted to the drum before the toner applied on it. One of the commonest characteristics of laser printers is their printing resolutions.

Usually they offer resolution between 300 dots per inches (DPI) to 12 dots per inches. They are also capable of producing variety of fonts by means of two ways font cartridges and font soft. They are also considered very fast printers and their printing capacity is 4 to 20 texts pages per minute.

How it Works

With the few remarkable differences the laser printers work in the same way as the photocopier machines. Laser printer works on the static electricity.

Inside the printer there is revolving drum or component that is known as photoreceptors. The photoreceptors are considered as a key component in them. Other basic components that make up a laser printer includes discharge lamp, toner hoper, laser scanning unit, fuser, developer roller, photoreceptor and drum assembly. The charge corona wire gives the positive charge to the drum inside the printer. The printer omits a laser beam across the surface as the drum revolves.

The text and graphics is printed as a pattern on electrical charges. After this the drum gets positively charged with a black powder known as toner and it gets attracted towards the negatively charged area of the drum. Some printers use a stream of light emitting diodes (LEDs) instead of a single laser light.

Printer Buying Tips

Before buying a printer you may think about your printing requirements. Whether you want to print basic black and white text, color text, graphics or you need high quality printing. If you need high speed, precision, excellent printing quality and accuracy then you may go for the laser printers. The toner cartridges are expensive as compared to the inkjet printers but they last for a long time as compared to the inkjet cartridges. Before buying you should examine the extra features such as USB ports and Ethernet port etc. Also check if the printer is compatible with your computer or not. Based on the type of work, know the memory requirement and check if the particular laser printer, which you are going to buy, fulfils your memory requirements or not. Also try to choose a printer with enough paper capacity so you should not bother to put the papers again and again. Also make sure that the manufacturers of the printer are providing enough technical support and driver’s availability on their website.

Advantages

The most important advantage of the laser printers is their speed. They are fast enough to transfer the information to the printer device quickly. It allows you to print all the pages at a time rather than to print only a section of the page. Another advantage is that the use of the toner is much cheaper as compared to the use of the toners in the inkjet printers. It’s very handy to fill the toner cartridges. They can work for long time without any need of changing the toner cartridges and paper refilling. The most important factor, which I personally like is that the most modern laser printers comes with 3 in 1 or 4 in 1 features i.e. you can have printer, scanner, photocopier and fax machines all built-in in the printer. The same cartridge and papers are used for the multiple purposes like photocopy, printing and fax. This provides you ease of work and saves your precious time during work.

Conclusion

In short, the laser printers provide excellent text quality, graphics quality, free of noise printing and multiple features at one place. In addition the other major qualities are high speed, printing process, high memory, standard available fonts and the printing language.  

INTERNET FILTERING

Internet filtering is software that controls the online activities of the kids and helps parents to protect their children from the internet dangers and prohibited things for children such as pornography, alternative lifestyle, hate, gambling, violence sites and others. Internet filtering software is designed to block the access of those websites that you do not want to show to your children. These software work by filtering the certain keywords and enables you to control the internet use of your kids. This software prevents your children from being exposed to the inappropriate and prohibited use of the internet. Internet filtering software has best combination with the internet monitoring software. With both the software you can control all the activities of your children while they are online.

 

These software works in the background and you can review the files generated by these software to see what activities your kids have performed on the internet. Among the other benefits of the filtering software are to control the internet access of the employees of a company, chat filtering, popup blocking, report reporting, daily time limits customizable ports blocking. Today there is a large number of internet filtering software available and following is the overview of some of the best software.

Net Nanny

Net nanny is a best internet filtering software that provides wonderful filtering and protection system. It works with a large number of web browsers and operating systems. Some of the features of Net Nanny are filtering the URL, chat blocking, IM blocking, popup blocking, newsgroup blocking, remote management, peer to peer blocking and image recognition etc. It provides detailed log reports, history reports and graphical reporting.

Norton Internet Security

Norton provides the complete security package for your family. With the advanced customizable parental control features also comes with the privacy control features that prevent your confidential data from being theft on the internet. Norton Internet security when packaged with the Norton antivirus and Norton Firewall, it provides an excellent level of security, parental control features, safety from the hackers and internet threats.

Cybersitter

Cybersitter blocks the unwanted, objectionable and pornography sites on your computer. You can specify your own list of the websites, fix the time for internet usage and maintains daily log files. Cybersitter is a best suitable for the pre-teens, businesses, public and educational institutes. Cybersitter has received 5 times PC Magazines’ editor’s choice award.

CyberPatrol

Cyberpatrol is internet safety software that blocks access to the harmful sites and provides protection against the spyware, peer to peer files sharing program, phishing and internet threats. Cyberpatrol is best choice for the schools, libraries, businesses and children.

CyberSieve v2.3

CyberSieve v2.3 is an internet monitoring and filtering software and it monitors and controls the kids’ use of the internet.

Infrared Network Technology

Infrared Data Communication is a simple example of short range wireless network. The most important characteristics of IrDA Communication consist of range, angle and modulation. The Standard range of two devices in an infrared line of sight network is 1 m with low-power to low power is 0.2 m and Standard to low power: 0.3 m.

The minimum angle for cone should be Angle +-15°. Infrared Speeds vary from Speed 2.4 kbit/s to 16 Mbit/s. Two modulation levels are available in this communication consisting of Base band and no carrier.

Infrared Communication is very agile and is interrupted by various factors including angle, distance, noise and heat. Light waves also form an interruption pattern in Infrared Communication. Infrared Communication works on a few layers which constitute the complete Infrared Communication Protocol for Data Transfer and Communication between IrDA devices.

These Layers include IrPHY (Infrared Physical Layer), IrLAP (Infrared Link Access Protocol), IrLMP (Infrared Link Management Protocol), Tiny TP (Tiny Transport Protocol), IrCOMM (Infrared Communications Protocol), IrOBEX (Infrared Object Exchange), IrLAN (Infrared Local Area Network), IrS (IrSimple) and IrSS (IrSimpleShot). All these layers combine to form the Infrared Communication possible in this network.

The biggest drawback in infrared communication is its range and angle problems which makes its impossible for modern day mobility needs to be fulfilled by this protocol.

The operating frequencies are also very low which makes it more prone to certain distortion sources.

IrPHY is equivalent to Physical layer of OSI model and handles the Medium transformation rates and connectivity characteristics of IrDA Network which IrLAP is like the Data Link Layer in OSI model.

The main responsibilities of IrLAP include Access control, Discovery of potential communication partners, Establishing of a reliable bidirectional connection and Negotiation of the Primary/Secondary device roles. The Third Layer IrLMP can be further subdivided into First is LM-MUX (Link Management Multiplexer) which lies on top of the IrLAP layer.

It provides multiple logical channels and allows change of Primary/Secondary devices. Te second is the LM-IAS (Link Management Information Access Service), which provides a list, where service providers can register their services so other devices can access these services via querying the LM-IAS.

Tiny TP provide Transmission and Flow control features in IrDA Network. IrCOMM acts like a serial or parallel poert on top of transmission layer for application integration. IrSimple provides two functionalities including enhancing transfer rates 4 – 10 times by improving IrDA Protocol It also provides backward compatibility with other IrDA Protocols.

IrSS is used by Infrared Camera to transfer pictures to Printers. It has the functionality of TV remote control with transfer rates of up to 16 Mbps.

How to Secure Wireless Network ?

By configuring the security features such as 64 bit WEP, 128 bit WEP, MAC address filtering, SSID, WPA2 and TKIP, you can secure your wireless network from the hackers, intruders and uninvited guests. Implementing a wireless network in your home or office requires a planning. Wireless network provides mobility and free of wires environment.

Different protocols are security features are used for building and securing different types of wireless networks. While setting up the wireless network we have to setup an access point, which has antenna at one end and wire at the other end. The antenna on the Access point talks to the wireless LAN cards and sends traffic from computer to the access point.

Setting up your access point

If you want to setup a wireless network for your business then you will need to setup a full featured access point such as Cisco Aironet 350 series and if you want to setup wireless network for your home then a low end access point such as Apple AirPort or Linksys WAP 11 are best.

WEP is a process of encryption that saves your privacy and network from the unauthorized access. WEP is used to authenticate the users on the network and the security components are setup on both PCMCIA and the access point. WEP can be configured in 40-bit and 128 bit modes and obviously 128 bit mode provides more security. Even TKIP is relatively new and many access points and wireless cards do not support it but TKIP provides more advanced security features that WEP does not cover. TKIP provides more powerful encryption algorithm and constantly changing the encryption keys and hence make it more difficulty for the wireless hackers to attack the wireless network.

Filtering the MAC addresses is quite hard job if your network is very big so before purchasing the LAN cards, make a plan to buy LAN cards with sequential MAC address because they will be easier to administer. There is another option on some PCMCIA wireless LAN cards to change the MAC addresses. In this way you can specify the MAC addresses of your own range. If you have low end access point then your security will be limited to WEP and MAC address. With the higher end access point such as Cisco Aironet 350 you will be able to turn on the Temporal Key Integrity Protocol

First step in securing the wireless network is to disable the broadcasting features. Control the broadcast area so that signals may not leak because sensitive snooping devices can pick the wireless signals from the Access points.

Things to remember

1. Change the default administrator password of all the hardware and software. Lock each access point and change the password that is not easily guessed.

2. Use 128 bit WEP instead of 64 bit WEP. If you use 128 WEP encryption keys, try to change the encryption keys at least once in a month. Also enable firewall on the computers and routers.

3. Use SSID. Change the default service set identifiers and don’t use anything obvious like company name otherwise it will be easy for the hackers to find the system SSID of the network devices and access them. Also disable broadcast SSID because intruders can use the programs such as http://www.kismetwireless.net to sniff out SSID.

4. Limit access rights of the users. Set your access points to set the rights by the wireless cards with authorized MAC address. Try to position the routers and the access points safely.

5. Ban unauthorized access points. Don’t try to connect with the unprotected wireless networks because in this way your privacy can be leaked and your network can be insecure. Also restrict the unnecessary traffic so that only authorized person can be able to access the network.

6. Authenticate users by different authentication procedures and for this purpose install a firewall that supports VPNS connectivity and require users to log on. Also try to limit the network management work.

7. WPA2 is a newest security technology and if the networking components such as access points, PCMCIA cards and wireless routers support it, you must prefer to use it.

8. Use RADIUS server because it provides another layer of security feactures and the administration of the network.

9. Fix the number of the user addresses in the DHCP server so that no unauthorized person can access the network. Alternatively try to assign static IP addresses from a fixed range.

10. Try to have wireless dedicated hardware security in place. Airdefence.net is a server appliance that is used to connect to the sensors near the AP and protect the network.