Modem

Modem (Modulator and Demodulator) is typically used to send digital data over a phone line. The sending modem converts digital data into analog data, which can be transmitted over telephone lines, and the receiving modem converts the analog data back into digital form. This is used to connect to Internet.
Modems are available in different capacities.
-300 bps - 1960s through 1983 or so
-1200 bps - Gained popularity in 1984 and 1985
-2400 bps
-9600 bps - First appeared in late 1990 and early 1991
-19.2 kilobits per second (Kbps)
-28.8 Kbps
-33.6 Kbps
-56 Kbps - Became the standard in 1998
-ADSL, with theoretical maximum of up to 8 megabits per second (Mbps) Gained popularity in 1999