As we know that the computers can’t understand our language. Computers understand the language of 0’s and 1’s i.e. digital form. The modem will modulate the signal into a sine wave. So, this modulated digital signal can easily run over the telephone lines. Then the signal will reach the IP hub. After this the demodulation of the signal will take place into digital form. Then you will be connected to the internet. All these processes are performed by modem at extremely high speeds. The speed of the modem depends upon the number of the available access lines and the technology of the modem.
Today’s the modems are of very high speeds. But some people are still using the slow speed modems having speed nearly 56kbps.
The features of modem are discussed below:
1. The speed of the modem is measured in bps means bits per second. Data transfer speed can be increased by using the technique of data compression.
2. If we are using a modem having auto answering facility. Then our modem will be able to attend calls even in our absence.
3. Modems work basically in two modes. One is voice mode and other is data mode. In voice mode modem acts like a simple telephone. But in data mode modem acts as a Simple modem. These types of modems have a switch which is helpful in changing the mode i.e. from voice mode to data mode and from data mode to voice mode. For voice communication, loudspeaker and a microphone is implemented in the modem.
4. Some modems have the ability to compress data. These modems compress data before sending to improve the data transfer rates. But there must be a similar technology modem to decompress the data at the receiver end.
5. There are basically three types of modems. All the three types are discussed in detail below:
a) External Modems
b) Internal Modems
c) PCMCIA Modem
External Modems: A serial cable connection is needed to connect an external modem to a PC. These modems use their own power supplies. These modems have their independent controls.
Internal Modems: Internal modems are basically integrated on a chip. These are put up into the PCI slots of the computer. There is no need of any external power supply for internal modems. These modems use the power supply of the PC. Their installation in PC is quite very simple.