A modem is a short name for modulator-demodulator. It is a program or device that modulates (encode) the digital information to analog form, and also demodulates (decode) the signal to produce the original transmitted information. In simple words, it is a device that enables computer to transmit data over the telephone lines. Speed of modem is generally measured in Mbps (Megabits per second) and Kbps (Kilobits per second).
An internet connection with good speed is required to use VoIP (Voice over IP) services, since VoIP calls are routed through internet connection. The use of modem is a must in internet, mostly DSL modems or cable modems are used in the internet.
A broadband modem or cable modem is a type of digital modem, which is used with high-speed cable internet service. It is used to transmit data over the internet with high-speed. It is often referred as “high-speed” access to the internet. It transmits the multiple pieces of data simultaneously to increase the effective rate of transmission.
DSL is an abbreviation for Digital Subscriber Line, which provides digital data transmission over the telephone lines. This technology allows telephone and the internet to work over the same phone line without disconnecting the internet or telephone connections. DSL Internet service works only over a limited distance, and it is also not available in those areas where the local telephone infrastructure does not support this technology.
Differences between DSL modem and Cable modem are -
1. Speed – Cable modem provides faster speed than DSL modem. Cable modems approximately support bandwidth of 30Mbps, whereas DSL modems hardly support 10 Mbps. Speed provided by DSL modem is constant, while speed of cable modem varies according to the number of users using that connection.
2. Popularity – Cable modem is most popular in U.S. than DSL Modem.
3. Security – Cable and DSL modem provides different security models.
4. Cost – DSL modem tends to be cheaper than a cable modem.