Answer briefly:
(1) What are communication devices?
Ans. The devices which help us to communicate are known as communication devices. Eg : Mobile, Computer.
(2)Which are the sources of information?.
Ans. The sources of information are Printing press, Xerox Machine, Fax Machine, Post Office, radio and television.
(3)Explain the following:
(i) E- Mail : Electronic mail is used for sending, receiving and writing messages through internet.

(ii) Teleconferencing: Teleconferencing is uses telephone lines to connect two or more computers and modem, for holding  a meeting between people in remote areas or workplaces.