A network is the foundation of network equipment, communication cable (media >, communication protocol and software. In the development of the network process, invented all kinds of network equipment, the equipment through the communication medium, constitute the connecting our network. In the network equipment, the most common is the following:

modem

Modem, Modem Modulator/Demodulator, namely the abbreviations.

In the early days of computer network, a modem is the most commonly used network access devices, it is the role of the computer links to telephone network.

The composition of the modem includes baseband processing, demodulation, amplification and filtering, balanced a few parts, etc.

Popularly say, modem the function of the one is put the computer in digital information can be transmitted to add in the telephone network of analog signals and instead of the process.

The modulation is the process of loading process, digital HP CQ45 battery signal demodulation is received from the mode of the signal to extract the digital signal process.

Note that the use of modem to pairing, also is your computer to through the-with a modem and another computer communication, if he must also take the computer have a modem.

Choose a modem is one of important index of the transmission rate per second, which is the transfer of digits, the unit is bit/s, abbreviations for BPS.

At present the main use of several communication rate is 14.4 KBPS, 28.8 KBPS, 33.6 KBPS and 56 KBPS modem.

Modem equipment in the form is the outer type, built-in, PC KaShi, frame type and circuit built-in 5 kinds.

The outer type is a small box, through serial communication, and the host connection mouth. The modem the greatest characteristic is very intuitive. The Modem communication and instructions have state indicator connection status.

Built-in general for desktops, is a insert CARDS. Built-in installed in case of expansion slot on the inside, saving the installation space and cable, also do not need additional power support. The connection is quite simple, the telephone Line joints of inserting the card “Line” in mouth, card another interface “please”, and telephone connected, at ordinary times unused device, the solution to a telephone with a little affected. Built-in shortcomings is need to be in on the project interrupt and COM port setting, installation more red tape.

PC KaShi, mainly used in notebook computers. Here the PC card is the abbreviation of mouth. Pick up PCMCIA PC KaShi Modem volume is small and exquisite, easy to carry, which is very suitable for travel.

Rack-mountable main used to provide the communication network access to company or a center machine room. A group of Modem is to focus on a box or covering, share a power, to provide users with Internet access.

Circuit built-in main notebook computer. Laptop computers in general have internal HP presario a900 battery adjustment of the circuit and modem I interface, the interface is RJ11 interface, also is the telephone interface.

In the foreseeable future, as the Internet broadband access and wireless access way, growing popularity of the modem will be eliminated.