What is a Modem?
A Modem is short for modulator-demodulator. It is an electronic device for converting computer digital signal into a specific frequency to travel over cable line or telephone line. At the end of destination, the receiving modem will demodulate the frequency back into digital data.
Modem is used for communicating from one computer to another in a network.
There are many types of modems as list below.
1) The modem was created since 1970s as 300 baud modem.
2) Back to 1998, the standard modem is dial-up modem which comes with transmission rate at 56 kilobits per second. This modem does not allow phone call when browsing internet.
3) Later, ASDL modem came to the market. This modem is faster at downloading (getting data) than uploading (sending data). It also let people use telephone while browsing, because it does not tie up the phone line like dial-up modem. This modem only works with ADSL service from ISP; it cannot work with a dial-up account.
4) However, some businesses need large bandwidth for downloading and uploading. For equal bandwidth in both directions, SDSL account and SDSL modem are required. SDSL use voice traffic for expand bandwidth, so calling is not possible while SDSL modem is connected.
5) Cable modem is another type of modem which uses cable TV wire instead of telephone line.
6) There is another type of modem; it is a satellite modem, or satmodem. This is a less common one. It is optional, and it often used in rural area where there is not DSL or cable service available there.
In conclusion, there are many types of modems; they are compatible to each of internet service.