Ok here's the scoop.
 
Network cards are designed to allow computers to communicate. Your USB adapter is actually a network card too (though it is external). To see that open the control panel and then open Network (or Network Connections). Now a cable modem usually has a network port on it to allow a computer to connect to it. Your computer would need a network card for this.
 
Now if you want to connect two computers (to share Internet for example) you would need a network card in each one. You could then buy a hub (or network switch) and some network cable and you're off. (Note you could also use a crossover cable to connect the two computers, via their network cards, thus removing the need for a hub or switch).
 
Hope this helps.

so...in very simple words...a network adapter is like a decoder ???
if it is ,then it's like a modem only with larger bandwidth..isn't it ??
and then again...if it is like a modem why another modem is needed ???
 
why does a Cable modem needs to be connected to a network adapter while an ADSL modem (mine at least) does not ??
 
and what is a hub ?......physically ??
 
i know i'm asking a lot ....i'm new at this..

You could say a network adapter is like a modem. They certainly both serve the same purpose, and they both use some method to encode/decode data while it transfers over a network line (i.e. phone wire, coaxial cable, ethernet cable, etc.).
 
Sometimes you need a second device to connect to the Internet, and sometimes you don't. Most modern cable modems and DSL modems have two methods to connect: an ethernet port, and a USB port. The USB port allows you to connect the modem directly to your computer. The ethernet port requires your computer to have a separate ethernet adapter (the subject of this whole discussion). To share a DSL or Cable modem connection, it's usually easier to use the ethernet port instead of the USB port.
 
The terms hub, switch and router all fall into a similar category. In my opinion a hub is not worth talking about, because a switch provides you better functionality for the same price. A switch connects several computers together, which in essence forms a network. Without an Internet connection, you could use a switch to share files and printers between several computers in one location. With a DSL or Cable Internet connection you can share Internet by connecting the switch to the modem's ethernet port.
 
One catch is that to share an Internet connection using a switch, you have to purchase more than one IP address from your Internet provider, and that cost can add up. The most widely used alternative is to skip buying a standard switch, and instead buy a router. A router is a switch that has even more functionality. It allows you to share an external network connection (such as the Internet) by providing an IP address to each connected computer.
 
In summary, not all DSL and Cable modems require a network card, but some do. If you want to share the Internet connection, then your best bet is to buy one network card for each computer, and then connect them all to a router. Most of today's routers have very good instructions about how to share an Internet connection.

thanks ..!!!

A NIC is not a modem in any sense of the word. A modem's purpose is to change the data it receives in order to transmit it over another medium and to take the data it receives and reconstitute it to its original state.
 
A NIC speaks only one "language", be it Ethernet, Token Ring, etc.
 
Your cable and/or DSL modem serve to take the information off the cable or phoneline and convert it to, in most cases, an ethernet format.
 
As mentioned above, your USB adapter acts as a NIC in this case through the drivers you installed on the PC for it. The issue with the USB scenario is that you can only connect one PC in this manner due to limitations in USB. Using a SOHO router, you can connect multiple PC's via ethernet connections to share a single connection.
 
Hope I was at least somewhat clear on this.

i missed something...
 
what is a NIC ?

Hi again,
 
First NIC refers to Network Interface Card (short for Network Card).
 
First I want to clarify a few things. Network cards and Modems work similarly in that they allow computers to communicate. Franzj and zen69x are both quite correct. A modem is similar to a NIC though in that it allows to computers to communicate. A modem has to convert digital signals to and from Analog (as phone lines are mostly analog). That's where modem comes from (Mo Modulate dem Demodulate). A network card does speak Ethernet (or Token Ring etc) and is functionally quite different than a modem though both allow TCP/IP (a network protocol - or the language used by all computers on the Internet) to be used. With respect to speed: a modem is quite slow. Virtually any other connection type (ADSL, CABLE, Wireless, Satellite) is much faster than a modem.
Now.. the difference between a hub, switch, router A hub is basically a dumb device that allows computers to communicate. It uses network cable, the hub itself, and NICs in the computers. Why is it dumb? Let's say for example a hub has 8 ports (or 8 plugins for network cable). If one machine on Port 1 is trying to send some information to another machine on Port 5 all the information will be forwarded to every port. Basically the hub receives information, then forwards it out every port it has hoping that the receiving computer will get it. This is wasteful as it can quickly flood your network with garbage traffic. (Think about it if you had more computers. Each other computer would have to spend processing time analyzing the data just to determine that the data isn't for them).
A switch isn't dumb like a hub. It will look at the data and try to figure out which network port it should go out on and then send it out only on that one port.
A router is even smarter because it will analyze the data even further (by IP number for example - don't worry if you don't understand what this is) and make better decisions on which port it can go out. Routers can usually (unless they are very cheap ones) block ports as well. This can prevent many cyber attacks and even many virus's.
 
For the next part I'm going to assume you want to share an Internet connection between two computers. For this you definitely do not have to have a hub switch or router. If you buy two identical network cards (or two that have either the same speed - for example 100mbit ) you can put one in each computer and hook them together directly - ie one cable goes from one computer directly to another. The cable has to be a crossover cable. You can buy this in a computer store.
 
If you want to go the hub/switch/router route then buy one (cheap hub/switch is around $60 or less). Note with a two computer network there is no benefit to a switch over a hub. Buy either one (unless you may be adding more computers to your network later). You'll still need two network cards and two network cables. Network cables look like thick phone cables with giant plugs on them (Phone cable ends are usually called RJ11 and network cable ends are usually called RJ45).
With either method you can share an Internet connection. No router needed.
 
Let me know directly if you'd like more information. I'd be happy to walk you through it via telephone or email.
Live Long and Prosper!
 
jamesmeszaros@yahoo.com

jimbo ....you Live Long and Prosper!
 
i learnt a lot from your answer...thanks ..!! 8)
 
now ...why does a cable connection to the internet requires a nic and a modem ??
 
you said a nic is the high speed modem...or did i confuse something..

You need the cable modem to decode the signal from coax cable to something your computer can understand. The modem then has output(s) on it to plug into your computer via ethernet (network interface) or via USB. If you have a cable modem that only has a RJ45/ethernet connection you must use a NIC or network interface card. If your cable modem only has USB then you must have a USB cable to plug into your computer and the modem has the NIC internally.
 
A regular modem only works on phone lines for dial up internet and faxing. A NIC is used for networking and broadband internet connections. I never trusted USB for broadband.... don't know why.

now i get it...i think...
 
according to that logic...my ADSL modem which connects to my pc via USB has an internal nic ...
 
am i right ??

Not exactly, the USB system in your computer is acting as a network bridge. USB can (in a sense) act as a network, and a network bridge converts two different types of networks.