Different types of computer modem.

Guidelines about Computer Modem

Different types of computer modemkeeps everyone connected, through the Internet technology, wherever they are. Let’s see what a computer modem is.

Modem, as a shortened form of MOdulatorDEModulator, allows the computer to convert data in useful information.

When it receives an analog data through a connection, it has to convert it in digital data to be usable by the computer. Likewise it reverses the action when it has to send data.

It is not so important, here, to know how modems do work but it is essential to make the difference between the different types of computer modem.

Internal computer modems. Some computers have an internal modem which can be a built-in modem or a PC card modem.

For the PC card modem, a PCI slot or even sometimes an ISA slot is required, depending on the available interface your motherboard uses to receive the modem.

Internal comuter modems are used with Dial-Up Internet connection through a couple of RJ-11 connection. Also called copper telephone lines, the RJ-11 allows computer to receive and send data as explained above.

Internal comuter modems are usually 56K modems which mean that the modem is able to receive 56 Kbits/s (56 kilobits or 56000 bits per second) of data. This kind of data transmission is called downstream transmission, came from a provider and transmitted over telephone lines. Commonly it is the standard bandwidth with telephones lines.

However because Internet is a two-way system, data must also flow from the client to the (server) provider. For this purpose the computer can use 56K modems V90 to flow back 33.6 Kbits/s of upstream transmission rate. On the other hand the 56K modems V 92 is able to provide 48 Kbits/s of upstream transmission rate.

External modems. It is the second term we have to consider from different types of computer modem. An External modem can be used to the same purpose and in the same conditions as internal computer modem. However external modem is a small box that uses other kind of interfaces to be connected to the computer.

It could be a serial modem, named thus because it uses the serial port to connect to the computer. Usually installed on the back of the computer, the serial port is an easy-to-install option for the external modem. The same small box, on the other hand, can be an USB modem which normally uses USB port usually placed on the back or in front of the computer.

First of all external modem can be a Dial-Up modem but more expensive than the internal.

As well as another type of external modem you may consider two important types of modem: cable modem and DSL modem if you need high-speed internet services. All ISPs usually supply a specialized modem named digital modem in the broadband package.

It’s important to notice that cablemodem has to connect to an Ethernet card, placed on the computer PCI slot to provide a broadband internet connection to the user. This is true if you opt to use Ethernet connection. However you won't need it if your option goes to use an USB connection.

Cable modem. The cable modem uses a coaxial cable television lines to provide a greater bandwidth than the dial-up comuter modem. An extremely fast access to the Web is providing by the cable modem with downstream transmission up to 38 Mbits/s and an upstream transmission up to 1 Mbits/s.

Unfortunately this transmission rate fluctuates with the number of users because of the shared bandwidth on which the cable technology is based.

DSL modem. DSL (Digital Subscriber Line) modem is exclusively used for connections from a telephone switching office to the user. This technology, available and frequently usable, split up into two main categories:

ADSLor Asymetric Digital Subcriber Line is used in North America and supports from 1.5 Mbits/s up to 9 Mbits/s of downstream transmission rate and up to 3 Mbits/s of upstream transmission rate.

SDSL. SDSL or Symetric Digital Subcriber Line is used in Europe and has the same data rates for downstream and upstream transmission which is 128 Kbits/s.

One more thing

Some modern modem include very interesting features which allow your computer to do important tasks such as auto-answer your incoming calls, do voice mail, sending and receiving fax …and so forth.

Don't waste your time! Go enjoy these various possibilities offered by the different types of computer modem.