Q. 4. What are advantages and disadvantages of parallel transmission?
Ans. Advantages: Advantage of parallel transmission is speed. Because there are dedicated wire
paths which are used to send the bits simultaneously.
Disadvantages Disadvantage of parall
Q.30. How we can convert digital data into digital signal?
Ans. Line coding is the process of converting binary data, a sequence of bits, to a digital
signal. As an example data, text numbers, graphical images, audio and video that are stored in
Q. 10. What are the various applications for simplex and duplex?
1. AM and FM broadcasting
2. TV broadcasting
3. Cable IV
4. Facsimile (Fax)
2. Two-way radio
5. Local Area Network.
Q. 11. What are the ad
Q. 29. Difference between analog and digital data transmission? And which is the best way
As a technology analog is the process of taking an audio or video signal (the human voice) and
translating it into electronic pulses. Digital on the
Q. 9. What is data rate?
The maximum number of bits of information which can be transmitted per seconds is data
transmission link. Typically expressed as mega bits per second (mbps). This shows the speed at
which data can be transmitted between devices. T
Where, Bandwidth is the bandwidth of the channel, SNR is the signal-to-noise ratio, and
capacity is the capacity of the channel in bits per second. The signal to noise ratio is the
statistical ratio of the power of the signal to the power of the noise. Th
Q. 20. Write disadvantages of analog signals?
The most popular disadvantages of the analog system is random variation. As the signal is
copied and recopied, or transmitted over long distance, these random variations become
dominant. Electrically, these lo
(ii) To connect co-axial cable to devices, we need coaxial connectors. The most common type of
connector used today is the Bayone-NeiIl-Concelman, or BNC, connectors.
Fiber-optics cable connectors
Fiber-optic cables use there are different types of connec
Q. 26. How fast is DSL? What are the various fields DSL use with some advantages and
disadvantages of DSL?
Ans. DSL services transfer data at speed ranging from 128 Kbps (IDSL) to a potential 9.0 Mbps
(HDSL) downstream. Up-stream speeds range from 128 Kbp
Q. 21. What is DSL and explain various types for that?
Ans. Digital Subscriber Line (DSL) service is one of the most exciting technologies to come to
market in the area of information access. The concept is as elegant as it is simple-DSL achieves
Q. 31. Can we convert an analog data into digital signal? How?
Ans. Sampling is the process by which the analog signal is sampled, we can store the binary data
in the computer or use line coding to further change the signal to a digital one so it can be
Q. 21. What are various communication channel modes?
There are basic three data transmission modes. These are
Simplex-In this communication mode, the data flows in only one direction i.e. sender always
remain a sender an
Chapter 3: Encoding and Modulating
Q. 1. What is dc component?
Ans. When the voltage level in a digital signal is constant for a while the spectrum creates very
low frequencies, called dc components that present problems for a system that cannot pass low
Q. 25. Explain with pin diagrams of EIA-449 interface.
Ans. EIA 449 interface Standard in case of EIA 232 the data rate is restricted to 20kbps and the
cable length to 50 feet. The EIA and ITU-T have introduced the EIA 449 standard for users who
Local Area Network (LAN).A local area network (LAN) is usually privately owned and links the
devices in a single office, building, or campus (see Fig.). Depending on the needs of an
organization and the type of technology used, a LAN can be as simple as t
Q. 5. What are the characteristics of sine wave?
Peak amplitude of a signal represents the absolute value of its highest intensity, proportional to
the energy it carries.
Period and frequency refer to the amount of time, in seconds, a signal used to compl
Q. 23. What are DCE and DTE for Ethernet?
Ans. Most data communication protocols specify communications between two types of
equipment. Typically, one is called DTE (Data Terminal Equipment) and the other is called DCE
(Data Circuit-Terminating Equipment)
Q. 32. What is the way to convert digital data into analog signal?
Ans. Converting binary data or a low pa analog signal to a band-pass analog signal is
traditionally called modulation.
Modulation of binary data or digital-to-analog modulation is the proc
Q. 26. Difference between error control and flow control.
Error control: In data communications, errors are inevitable. Using better equipments and more
reliable transmission media may reduce the severity or the frequency of occurrence, but it can
Q. 17. Define the difference between synchronous and asynchronous transmission.
A start bit and a stop bit are added to each data segment for asynchronous communications. For
synchronous communication, but the start bit and stop bit are eliminated. So a f
Q. 14. How is the baud rate related to the FSK?
Ans. The bandwidth requirement in FSK can be calculated by.
The .bandwidth required for FSK transmission is equal to the baud rate of the signal plus the
frequency shift (difference between the two carrier f
Chapter 5 : Multiplexing and Switching
Q. 1. Define multiplexing.
Ans.Multiplexing is the set of techniques that allows the simultaneous transmission of multiple
signals across a single data link.
Q. 2. State the importance of multiplexing.
Ans.To make ef
Q.26. What are the measurements available in the data communication?
The four measurements used in data communication are throughput, propagation speed,
propagation time and wavelength.
Throughput: The throughput is the measurement of how fast data can pa
Q. 16. What are the advantages of X-21?
Ans.1. The advantages of X.21 standard over RS-530 standard is that X.21 signals are encoded
in the serial digital form.
2. This allows the provision of special new services in computer communication.
Q. 17. What is
Chapter 2: Transmission Media
Q. 1. What is Transmission Media?
Means by which a communication signal is carried from one system to another (for example,
twisted-pair wire, co axial cable, fiber-optics cable) and wireless links (for example, satellite,
Chapter 1: Introduction
Q. 1. Explain the data transmission concept?
Data transmission is the moving of data in the form of electromagnetic signals across a
transmission medium. As an example, when you are collecting numerical statistics
Q.33. What is the method to change the analog data into analog signal ?
Ans. Modulation of an analog signal or analog-to-analog conversion is the representation of
analog information by an analog signal.
Analog-to-analog modulation can be accomplished in
Q. 14. What is Periodic and Aperiodic Signals?
A periodic signal completes a pattern with in a measurable time frame, called a period and
repeats the pattern over subsequent identical periods. The completion of one full pattern is
called a cycle. An aperi
Q. 28. What is RS-530 standard explain pins for this standard?
Ans. Interface Standards: RS-530 (often written as RS530) is a specification for differential
communication interface that uses a DB-25 connector and differential equivalent of the \-24
Q. 23. What is serial and parallel transmission?
2. Parallel Transmission:
Serial Transmission: In this transmission the data is transmitted serially over the line. As signal
wire pair can carry the signal so generally preferred for long distanc