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Ethernet card, also known as network interface card (NIC), is a hardware component used by computers to connect to Ethernet LAN and communicate with other devices on the LAN. The earliest Ethernet cards were external to the system and needed to be installed manually. In modern computer systems, it is an internal hardware component means it comes with motherboard now a days.
NETWORKING CABLE
The twisted-pair cable is also known as Ethernet cable OR Networking cable. Almost all modern LAN computer networks use this cable.

This cable consists of color-coded pairs of insulated copper wires. Every two wires are twisted around each other to form pair. Usually, there are four pairs. Each pair has one solid color and one stripped color wire. Solid colors are blue, brown, green, and orange. In stripped color, the solid color is mixed with the white color. All wires are arranged in special order and RJ-45 connector is crimped at both side of cable.
HUB
 A hub is a device that is used to connect computers in a network In a hub, when one computer sends data on the network, the hub simply forwards the packets to all the other computers connected to it . Each computer is responsible for determining which packets are destined for it and which are to be ignored.
SWITCH
A switch is a device that is also used to connect computers in a network .However, a switch is a more intelligent device than a hub. Unlike a hub, the switch sends the incoming data to the desired destination only. It records the addresses of all the computers connected to it. So, when a packet is received, the switch reads the information about the destination address to determine if the destination device is connected to it or not. If the destination device is connected, the switch forwards the packet only to that destination device. In this way, the other computers do not have to read and deal with data that is not meant for them.
ROUTER
It used in mostly wireless networking. It connects two or more networks or subnetworks. It allows multiple devices to use the same Internet connection and manages data traffic .

MODEM

Modem is a device that enables a computer to send or receive data over telephone . The data stored on the computer is digital whereas a telephone line or cable wire can transmit only analog data. The main function of the modem is to convert digital signal into analog and vice versa. Modem is a combination of two devices − modulator and demodulator. The modulator converts digital data into analog data when the data is being sent by the computer. The demodulator converts analog data signals into digital data when it is being received by the computer.

Wi-Fi CARD / WIRELESS NETWORK CARD
Wi-Fi card is a card used to connect any device to the local network wirelessly. Most of the laptops come with inbuilt wireless network card.

A network in which all the computers have equal right and are suitable for only small geographical area such as small rooms, building, school, etc. is known as peer to peer network. Some of the disadvantages of peer to peer network are as follows: It has low level security than the client-server network.
In Client Server Network computers are connected to a central device (server) and communication is done through it. The server is the main computer which provides services to the workstation.