Friday, January 8, 2016

Connecting to the Internet

MODEM

Modem stands for MODulator/DEModulator. Telephone lines were designed to transmit the human voice, not electronic data from computers, modems were invented to convert digital computersignals into a from that allows them to travel over phone lines.

Two Kinds of Modem
  • Internal Modem
  • External Modem

INTERNAL MODEM
Internal Modem

 is modem that plugged directly into the CPU. Physically internal modem in the form of a card that is plugged into one of the expansion slots on the mainboard, usually on the ISA or PCI slot. The use of this type of modem has several advantages, among others, are more efficient in terms of price point and more economical than an external modem. Since it has been installed on the CPU, then this type of modem does not require an adapter as well as an external modem to the system seem more concise without a lot of wires milling which could give the impression of less neat. Nevertheless, internal modem has a drawback as the absence of indicators that can be found on the external modem. Consequently rather difficult to monitor the status of the modem (though it can be done through software). In addition, internal modem does not use its own voltage source to be fed from the power supply to the CPU. The heat from the components in the circuit will also add an internal modem in the box CPU temperature.

internal-modem


External Modem
 is modem that installed outside of the CPU. External modem connected to the CPU via the COM port or USB. This type of modem typically uses separate voltage source in the form of an adapter. The advantage of using this type of modem is a pretty good portability so that to be easily removable for use on another computer. Besides, by using an external modem, there should be no expansion slots are sacrificed so that it can be used for other purposes, particularly if used mainboard provides few expansion slots. External modems are also equipped with an indicator light that allows us to monitor the status of the modem. Disadvantage, more expensive than the internal modem. External modems also require a separate place to put it though small.
external-modem

BROADBAND


While all Broadband services make dial-up seem glacial by comparison, not all deliver the same speed. Most Broadband services are asymmetric, a fancy term that means, that the download speed is faster than the upload speed.




CABLE

Another option is high-speed Internet Access via cable TV. with speeds ranging from 512 kbps to 20 mbps, cable modems download data in seconds that make fifty times longer with a dial-up connections.








DSL


DSL, short for Digital Subscribers Line, employs an unused portion of your telephone line, so there's need to install another one into your home or office. Those living closest to the local exchange enjoy the fastest speeds.





SATELLITE


with Satellite Internet Access, you connect via the same satellite dish you use to receive TV programs. These systems can be one-way or two-way; Satellite is an option, although an expensive one. Just as bad weather may affect satellite TV reception, the same is true for Internet Service.







WIRELESS NETWORK


This relatively new service delivers speddy Internet Access via radio waves. WIFI is typically used in private wireless networks in homes and offices or in public places like airports or cafes.