Modem

The expanded form of Modem would read as Modulator Demodulator. Modem is a device which regulates analog carrier signal to process digital information. The modem encodes digital information and decodes transmitted information. RS-232 is a standard interface that connects computers to external modems. Any external modem that is compatible to this interface can be attached to the computer. These modems could come on an expansion board which is known as internal modem. Modems contain different protocols which help in transferring data. Modems are distinguished among themselves by values like data transfer rates, capacity to transfer voice or data, auto-answer capacity, data compression, flash memory and fax capability.

Types of Modems

The different types of modem are USB modem, wireless modem, fax modem, PCI modem, external modem, internal modem, software modem, on board modem, answer only modem, host based modem and direct connect modem. Modem is the most economic form of connecting the computer to the internet without much wiring either. Modem also connects the computer to many other devices.

ADSL and SDSL Modems

Asymmetrical Digital Subscriber Line or ADSL modem downloads faster than its uploading capacity. ADSL modem is advantageous than dial up modem. ADSL modem is compatible for telephone conversation because it has a dedicated copper wire for the purpose. Some commercial activities which require the same speed for uploading files and downloading data can use the symmetrical DSL or SDSL. However SDSL does not encourage voice conversations. Certain business houses have dedicated phone line with their SDSL connection.

Another scarcely used modem is the satellite modem. The digital data is converted to radio waves and are absorbed by the satellite dish. Satellite modem is a good choice for rural areas which could not have the infrastructure for other modems. The router connects the modem and a computer thereby allowing many other computers to use the broadband facility.

Wireless routers connect the computer and broadband without the need for wires which avoids clutter in work or home. The time unit of the modem is measured in bits per second while the symbol rate is measured in bauds. Baud is the number of times the signal changes in the modem per second. Modem is found very useful for internet service providers, home networking and deep space telecommunications. Voice Modem which helps in telephony applications has gained popularity in the recent times. Thus modem has become an indispensible part of computer and telecommunications.

Questions:

• What is the function of the modem?
• What are the different types of modem?