Telecommunications– MISY3312
Mid Term 1 Duration: 1 hr
Summer Semester
Student Name: __________________________ ID: ____________________
30 total points (15 % towards the final score)
Part 1: Total Points 10(1 Point each)
Q1. The ________________layer is responsible for translation, compression, and encryption of
data.
a. Presentation
b. Physical
c. Data Link
d. Application
Q2. The _____________ layer Converts bits into electronic signals for outgoing messages.
a. Transport
b. Network
c. Physical
d. Session
Q3. The difference between the maximum and minimum signal heights is
called________________
a. Frequency
b. Amplitude
c. Bandwidth
d. Phase
Q4. The difference between the highest and lowest frequencies of the constituent parts of an
analog signal is called__________________
a. Wavelength
b. Frequency
c. Amplitude
d. Bandwidth
1|Page
Q5. If a system that operates at 1000 baud has four signal levels then the system can transfer
___________________ bits per second
a. 1000
b. 2000
c. 3000
d. 4000
Q6.A digital signal represents ___________________
a. Continuous mathematical function
b. Bits
c. Bytes
d. All of the above
Q7. If the time required for one cycle of a signal is 2 seconds then the frequency will be
___________
a. 0.5 Hertz
b. 1 Hertz
c. 1.5 Hertz
d. 2 Hertz
Q8. By the____________ applications arose that allowed users to transfer images easily
a.1960
b.1970
c.1980
d.1990
Q9. The ___________ layer is responsible for dialog control and synchronization.
a. Presentation
b. Transport
c. Session
d. Application
Q10. _______ Waves are especially important in information sources because natural
phenomena produce it.
a. Sine
b. Cosine
c. Tangent
d. Both a & b
2|Page
Part2: Short answer Questions. Draw diagram where applicable. Total Points 12(3 Point
each)
a. Differentiate Synchronous and Asynchronous communication
Synchronous communications
◦ Receiver gets message instantaneously
Asynchronous communications
◦ Receiver gets message after some delay
b. Define the following characteristics of a signal.
Frequency:
The number of oscillations per unit time (usually seconds)
Amplitude:
The difference between the maximum and minimum signal heights
Wavelength:
The length of a cycle as a signal propagates across a medium, is
determined by the speed with which a signal propagates
c. Define Bit and Baud
Bit is the basic unit of information in computing and digital
communications.
Baud is how many times the signal can change per second.
d. Periodic and (Non) (A) periodic signal
Periodic Signal is a signal which repeats itself after a specific interval
of time.
Aperiodic Signal is which does not repeat itself after a specific
interval of time.
3|Page
e. Modulation and Multiplexing
Modulation refers to the way electromagnetic radiation is used to send
information.
Multiplexing refers to the way information from multiple sources is
combined for transmission across a shared medium.
f. TCP/IP suite and OSI model
TCP/IP is the computer networking model and set of communications
protocols used on the Internet and similar computer networks.
Open Systems Interconnection (OSI) is a set of internationally recognized,
non-proprietary standards for networking and for operating system involved
in networking functions.
g. Dedicated circuit and Packet switching
A dedicated circuit is defined as - a circuit that serves only that
appliance.
Packet-switched networks move data in separate, small blocks --
packets -- based on the destination address in each packet.
4|Page
Part3: Describe the following. Total Points 8
1- How Data Passes through the Layers in OSI. Explain with diagram
2- Describe the history and growth of computer networking
Early computer networks were designed when computers were large and expensive, and the main
motivation was resource sharing. Networks were devised to connect multiple users. Later
networks allowed multiple users to share peripheral devices.
By 1960s ARPA planned to interconnect all computers with a network and devise software that
would allow a researcher to use whichever computer was best suited to perform a given task.
ARPA did the following to achieve the visionary work: gathered some of the best minds
available, focused them on computer network research, and hired contractors to turn the designs
into a working system.
In less than 30 years the Internet has grown from an early research prototype connecting a
handful of sites to a global communication system the rate of growth has been phenomenal. The
internet has had exponential growth for over 25 years Internet has been doubling in size every 9-
14 months
5|Page
