Computer Networking Concepts Modem Types Types of Modems

Computer Networking Concepts: Modem Types

Types of Modems There are many types of modems, the most common are: Ø Optical Modems Uses optical fibre cable instead of wire. The modem converts the digital signal to pulses of light to be transmitted over optical lines. (more commonly called a media adapter or transceiver) Ø Short Haul Modems used to transmit over 20 miles or less. Modems we use at home or to connect computers together between different offices in the same building.

Types of Modems Ø Acoustic Modem A modem that coupled to the telephone handset with what looked like suction cups that contained a speaker and microphone. Used for connecting to hotel phones for travelling salespeople. Ø Smart Modem with a CPU (microprocessor) on board that uses the Hayes AT command set. This allows autoanswer & dial capability rather than manually dialing & answering.

Types of Modems Ø Digital Modems Converts the RS-232 digital signals to digital signals more suitable for transmission. (also called a media adapter or transceiver) Ø V. 32 Modem Milestone modem that used a 2400 Baud modem with 4 bit encoding. This results in a 9600 bps (bits per second) transfer rate. It brought the price of high speed modems below $5, 000.

Types of Modems Baud is the speed at which the Analog data is changing on the Voice Channel and bps is the speed that the decoded digital data is being transferred.

References Introduction to Data Communications Copyleft Sept. 1999 - Jan 2005 TCP/IP Tutorial and Technical Overview An IBM Redbooks publication Published 19 December 2006 Computer Networking: A Top-Down Approach (7 th Edition) James Kurose & Keith Ross