3. A router is a device that forwards data packets
between computer networks. This creates an overlay
internetwork, as a router is connected to two or more
data lines from different networks.
The most familiar type of routers are home and
small office routers that simply pass data, such as
web pages, email, IM, and videos between the home
computers and the Internet.
6. A hub is used in a wired network to connect
Ethernet cables from a number of devices
together. The hub allows each device to talk to the
others. Hubs aren't used in networks with only
wireless connections, since network devices such
as routers and adapters communicate directly
with one another.
9. A modem (modulator-demodulator) is a device
that modulates an analog carrier signal to encode
digital information and demodulates the signal to
decode the transmitted information.
A common type of modem is one that turns the
digital data of a computer into modulated electrical
signal for transmission over telephone lines and
demodulated by another modem at the receiver side
to recover the digital data.
