May 3rd, 2012 | Tags:

What is a gateway,what is a modem,what is a server,what is a switch..?

What is a server?
A server is a special computer that has specific roles which it completes over and over again. They are most useful in a situation where you have a network of many computers which access the same files repeatedly. Servers are used for various functions but the most common ones ire to store those files that are used more often by many computers in the network and also in regulating internet traffic among the computers using this specific network. Servers make it possible for many computers in the same network to access the same hardware device like a scanner and a printer.

What is a server

What is a server

What is a gateway?
Gateways are devices which play a very important role in multi-network communications. They are devices that will help you route different networks that may be using separate protocols. A gateway device is used when one is setting IP or TCP settings which facilitate routing from one network to the other. They serve a very important role when you are connecting to the internet.

When setting up the gateway device, one is required to have a router or other hardware devices. A computer that has virtual gateway software installed can also be used to set up the gateway device. A gateway is configured to operate at any level of OSI model.OSI model is a model through which information moves around the network. While in use, a gateway device will maintain the same network ID just like all the other devices using the same network.

What is a modem?
A modem is a device that allows your computer to connect to another computer through your phone. Modems are very common devices which are used to connect to the internet. They are cheap in most parts of the world and very popular among those people who cannot afford to set up other forms of internet connections. There are people who consider modems to be inefficient as one modem cannot be used by more than one computer. That means that if there is more than one person in the house who needs to use a modem to connect to the internet, then you will need to have more than one modem.

There are different types of modems in the market. Those that are able to connect to the internet very fast will be more expensive than the slow connecting ones. In order to be able to use a modem, you will need to use a phone line which is supported by local telephone networks. The modem is connected to the computer via the USB port.

What is a switch?
A switch is a device which is used to direct the flow of information between different computers to the Wide Area Network or to the local Area Network. Servers will transfer information from Data Link Layer on the Open Systems Interconnection and then passes commands to Physical layer. A switch is built with multiple ports at the back through which different computers can connect via Ethernet cables. By using a switch, different computers can receive and send data without the risk of these data packets interfering or colliding with each other.

February 14th, 2011 | Tags: , ,

The Internet, today’s lifeline of communication, consists of hundreds of components, which when combined help us enjoy the technology. The Modem (modulator-demodulator) is a device that makes transmission of signals via telephone lines possible.

What is a Modem

Today, different types of modems are on the market: internal, external serial, or with external USB. The internal Modem is installed within the PC, while the external one just plugs into a cable: USB cable (USB Modem) or to the serial port (RS-232 serial Modem). External Modems are more expensive than internal Modems. The latter, preferred by many, come at a lesser cost, besides any data loss due to buffer overruns is minimal. Another advantage of the internal Modem is that it does not use up desk space.

Usually, the external serial modems are easier to install. They present less configuration problems, provided the serial port is configured properly. The external USB Modems, more likely to be win Modems, are usually more difficult to deal with as compared with the external serial Modems. The external Modems have LED lights, which indicate its operation and thus help in troubleshooting. Given the fact that the serial port and the Modem can be physically separated also helps the engineer to troubleshoot. Being a movable device, the external Modems are easy to shift to another computer.

Most external serial Modems have a switch to turn off the power supply when not required. Hence, they consume less electricity even when turned off. A possible disadvantage of an external Modem is that you will be forced to use an existing serial port, which may not support a speed of over 115,200 bps.

Many external Modems come as ‘Plug and Play’ (PnP) devices. If they are hardware Modems, they should all work as non-PnP modems. The PnP Modem has a special built-in PnP identification that can be read by a PnP operating system. Such an operating system would then know that you have a Modem on a certain port. If it is a controller-less Modem, it could try to locate a driver for it, or it could even identify the application programs as to what port the What is a Modem is connected (dev/ttyS2 or COM3). But this feature is not available in Linux, and hence you may need to configure the application program manually by giving it the ttyS number (dev/ttyS2).

Setting the IO address and IRQ for a serial port was earlier done by jumpers on the card. These are little black rectangular ‘”cubes’ of about 5x4x2 mm, which push in over pins on the card. PnP Modems do not use jumpers for setting them, but instead are configured by sending configuration commands to them over the bus inside the computer. Such configuration commands can be sent by a PnP BIOS.