Discuss modems, ISDN, and DSL. What types of data transfer speeds are each of these capable of? How are they typically configured?

What will be an ideal response?

Modem (modulator-demodulator) devices use PPP to send TCP/IP information across normal telephone lines. They were the most common method for home users to gain Internet access in the 1990s. Modem connections are considered slow today compared with most other technologies; most modems can only transmit data at 56KB/s. Because modems transmit information on a serial port, the system typically makes a symbolic link called /dev/modem that points to the correct serial port device, such as /dev/ttyS0 for COM1.?Integrated Services Digital Network (ISDN) is a set of standards designed for transmitting voice, video, and data over normal copper telephone lines. It allows data to be transferred at 128KB/s. ISDN uses an ISDN modem device to connect to a different type of media than regular phone lines. Although ISDN is popular in Europe, it does not have a large presence in North America.?One of the most popular connection technologies in North America is DSL. DSL has many variants, such as Asynchronous DSL (ADSL), which is the most common DSL used in homes across North America, and High bit-rate DSL (HDSL), which is common in business environments; for simplification, all variants of DSL are referred to as xDSL. You use an Ethernet NIC to connect to a DSL modem using TCP/IP and PPP; the DSL modem then transmits information across normal telephone lines at speeds that can exceed 100MB/s.?Because modem, ISDN, and DSL connections require additional configuration information that is specific to the ISP, they are not normally configured during the Linux installation and must be configured manually.