What is a modem?
A modem is required to bring Internet services into your home or business. Generally, your service provider will supply you with a modem which you “rent” from them for the duration of your service. Otherwise, you can buy and use your own modem to connect to your service provider. This is the first point of connection for global connectivity.
Dial-up Modems
Dial-up modems are pretty much obsolete and quite slow, but can be used to connect to the Internet if you have no other alternative.
Cable Modems
Cable modems connect through the same cable as your cable TV – they can be left connected 24-7 and are generally provided by cable TV and Internet providers.
DSL Modems
DSL modems connect through a phone line but leave the phone to be free for other purposes (i.e. voice calls and faxes), while the DSL modem is in use. DSL modems connect to the Internet at speeds of 256 kbit/s to over 100 Mbit/s and can be left connected 24/7.
Wireless Modems
Modems which use a mobile telephone system (GPRS, UMTS, HSPA, EVDO, WiMax, etc.), are known as mobile broadband modems (sometimes also called wireless modems). Wireless modems can be embedded inside a laptop or appliance, or be external to it. External wireless modems are connect cards, USB modems for mobile broadband and cellular routers. A connect card is a PC Card or ExpressCard which slides into a PCMCIA/PC card/ExpressCard slot on a computer. USB wireless modems use a USB port on the laptop instead of a PC card or ExpressCard slot. A USB modem used for mobile broadband Internet is also sometimes referred to as a dongle
Satellite Modems
Satellite modems tie into your satellite dish and give you two-way communications in remote locations. Although they’re typically not as fast as cable modems and DSL links, they’re better than dial-up.
Fiber-optic Modems
Optical modems provide much higher data transmission rates than are possible with other types of modems because of the extremely high capacity of the optical fiber cable through which the data is transmitted.