for my notebook, when I connect it to the internet ,I just take it to the Library and plug a cable into their socket and the other end goes into my Network Jack on the notebook , and presto I get internet on my notebook. So what is the Modem jack for on my notebook when it already has a modem built inside ? are the actual connections the same on both Jacks ? would I still get the internet on my notebook if I plugged it into the modem jack instead of the Network Jack ?

If your plugged the network connector into your network, what does that mean. Is it plugged into a Router. If so, your Router establishes the Internet connection for your notebook. The modem jack is, if you're in a hotel and need access to the Internet. So you can use a phone line to dial in to the Internet, when using the modem jack.

If you look closely....the two jacks appear to be the same but in fact ...one is much larger than the other. The smaller one is for the phone modem that is built in to the laptop. The larger one is for the NIC (networking card) that is installed but still requires a modem to be used. Note that when you are at somewhere else and are allowed to plug in then they have a modem and (possibly) a router all ready installed. Definition of a Liberal: He has never had to fight for his Freedom He is only good at enjoying it! "People demand freedom of speech to make up for the freedom of thought which they avoid."

You have two ports. One is an onboard NIC (Network Interface Card) and the other is an onboard modem. Your network port is for an ethernet cable; which is what you're using to connect when you're at the Library. This uses an RJ45 connector. "are the actual connections the same on both Jacks ?" No. "would I still get the internet on my notebook if I plugged it into the modem jack instead of the Network Jack " No. "So what is the Modem jack for on my notebook when it already has a modem built inside ?" They are not the same. The modem/phone port is if you were using a dial-up Internet Service Provider that requires a phone line. This uses an RJ11 connector, which is what you will see if you unplug a telephone and look at the connector on the end of the cable. Each port is identified as to the type of connection. The modem has a phone receiver to identify it. The NIC has a network diagram to identify it. Life's more painless for the brainless.

Network jack = RJ-45 Phone jack = RJ=11 The phone jack is smaller (2 pair or 4 wires) whereas the network is 4 pair (8 wires). You can plug an RJ-11 end into an RJ-45 socket, but unless the RJ-45 socket is wired correctly it won't work. It's worth noting that, this is only for a telephone connection - not a network connection. Where I work, we occasionally use RJ-45's for our telephone connectors and have to wire it especially for that or it won't work. The reverse can't work for obvious size reasons (ie: an RJ-45 end will not fit into an RJ-11 socket).

The smaller jack on your laptop is connected to a dial-up modem inside your laptop. You connect a telephone line to that if you want to connect to the internet via a relatively slow dial-up connection. The dial-up modem inside the computer is what connects you to the internet, providing you have or are using an ISP's (Internet Service Provider's) account service that has been paid for. The larger jack of the same shape is for a networking adapter inside your laptop. When you are at the library, you connect a network cable from that to a LAN (local area network) in the library, that connects you to a high speed modem, or a dedicated high speed line, that in turn connects you to the internet. In that case the high speed modem, or the high speed line connection, is external to your computer, and the ISP's service has been paid for/provided by the library's account. If you have a paid for service for a high speed internet connection at home, you connect a network cable from your computer to either a high speed modem that was provided by the ISP, or to a separate router which connects to a high speed modem that was provided by the ISP, or to a router/high speed modem combo that was provided by an ISP, and the coax cable or telephone cable that connects to the high speed modem or router/modem combo is what provides the connection to the internet.