4. 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. When a data
packet comes in one of the lines, the
router reads the address information in
the packet to determine its ultimate
destination.
6. Modem is a device that modulates an analog carrier
signal to encode digital information and demodulates the
signal to decode the transmitted information. The goal is
to produce a signal that can be transmitted easily and
decoded to reproduce the original digital data. Modems
can be used with any means of transmitting analog
signals, from light emitting diodes to radio. 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.
8. Gateway is a link between two computer
programs or systems such as Internet Forums. A
gateway acts as a portal between two programs
allowing them to share information by
communicating between protocols on a computer
or between dissimilar computers.
