Example -Telephone System

EXAMPLE-Telephone System o    Input to the Telephone is a message 'm' in the form of sound waves o    The  sound  waves  are  converted  by  telephone  into  electric  signals  of  the  same frequency o    These signals are transmitted w/o any modification over the telephone line o    Hence g(t) and s(t) are identical o    S(t) will suffer some distortion so that r(t) will not be the same as s(t) o    R(t)   is   converted   back   to   sound   waves   with   no   attempt   of   correction   or improvement of signal quality o    Thus m' is not an exact replica of m An Actual Digital Data Communication System Key Data Communication Terminology    Session: communication dialog between network users or applications Different Types of this session for Info Exchange ™   Network: interconnected group of computers and communication devices We will look into it in a little bit ™   Node: a network-attached device Node can be any device in the network