Differentiate Parallel & Serial Communication.
Basis Parallel Communication Serial Communication
Definition Sends multiple bits at Sends one bit at a time.
once.
Speed Faster. Slower.
Connections Requires multiple wires. Requires fewer wires.
Cost More expensive. Cheaper.
Distance Best for short distances. Works well over long
distances.
Usage Used in printers and RAM. Used in USB and Ethernet.
Interference More interference. Less interference.
What is Multiplexing?
Multiplexing:
• Multiplexing is a technique used in communication systems to send multiple signals or
data streams over a single physical transmission medium, such as a wire, fiber-optic
cable, or radio wave.
• It increases the efficiency of the communication channel by allowing simultaneous
transmission of data from different sources.
Key Features of Multiplexing
1. Efficient Use of Resources
2. Cost-Effective
3. Supports Scalability
4. Minimizes Interference.
Types of Multiplexing
1. Time Division Multiplexing (TDM)
o Allocates distinct time slots to each data stream.
o Time is divided into non-overlapping intervals.
o Example: Digital telephony.
2. Frequency Division Multiplexing (FDM)
o Allocates separate frequency bands to each data stream.
▪ All data streams are transmitted simultaneously.
o Example: FM/AM radio broadcasting.
Equipment Used in Multiplexing
1. Multiplexer (MUX): Combines multiple data streams into a single composite signal at the
transmitter's end.
2. Demultiplexer (DEMUX): Splits the composite signal back into individual data streams at
the receiver's end.
Explain Synchronous Communication
Synchronous Communication
• Definition: Synchronous communication transfers data in a continuous stream as blocks
or frames with synchronization between the sender and receiver.
• Key Points:
o Data flows in a full-duplex mode.
o Requires a clock signal to maintain synchronization.
o No gaps between data.
o Efficient and reliable for large amounts of data.
o Used for real-time communication.
• Examples: Chat rooms, video conferencing, telephonic conversations.
What is Asynchronous Communication? Give examples.
Asynchronous Communication
• Definition: Asynchronous communication sends data one byte (character) at a time with
start, stop, and parity bits for interpretation.
• Key Points:
o Data flows in a half-duplex mode.
o No clock required; synchronization happens using start and stop bits.
o Gaps between data are allowed.
o Simple, economical, and suitable for smaller data transfers.
• Examples: Emails, letters, forums, televisions, radios
Differentiate Guided Media, and Unguided Media
Basis Guided Media Unguided Media
Signal travels through a physical
Medium Signal is broadcasted through air or water.
path.
Wired communication (bounded Wireless communication (unbounded
Type
media). media).
Directio
Provides direction to the signal. Does not provide direction.
n
Twisted pair, coaxial, fiber optic
Example Radio waves, microwaves, infrared.
cables.
Interfere
Less prone to interference. More prone to interference.
nce
Cost More expensive to install. Relatively cheaper.
Used for LAN, telecommunication Used for Wi-Fi, satellite, and mobile
Usage
networks. communication.
Explain Time Division Multiplexing (TDM).
Explain Time Division Multiplexing (TDM)
Definition: In TDM, the transmission time of a single channel is divided into distinct non-
overlapping time slots assigned to different data streams.
Key Points:
• Data streams are divided into equal-sized units and interleaved in time slots.
• Each source gets a time slot to send its data.
• Used in scenarios with predictable and uniform data transmission.
Examples:
• Digital telephony.
• Satellite communication.
Explain Frequency Division Multiplexing (FDM).
Explain Frequency Division Multiplexing (FDM)
Definition: In FDM, multiple data streams are transmitted simultaneously on the same channel
by assigning different frequency bands to each data stream.
Key Points:
• Each data stream operates in its assigned frequency range.
• Suitable for analog communication.
• Ensures simultaneous transmission without interference.
Examples:
• FM/AM radio broadcasting.
• Cable television.
Write short note on Optical fiber media.
Optical Fiber Media
Definition:
Optical fiber is a thin, flexible, and transparent strand made of glass (silica) or plastic, slightly
thicker than a human hair, designed to transmit data as light signals.
Key Features:
• Material: Made of glass or plastic.
• Data Transmission: Uses light to transmit data, allowing for higher speeds and larger
bandwidths.
• Size: Diameter is slightly thicker than a human hair.
Advantages:
• Long-Distance Communication: Enables transmission over much longer distances
compared to copper cables.
• High Bandwidth: Supports significantly higher data rates.
• Immunity to Interference: Not affected by electromagnetic interference or radio
frequency interference.
• Lightweight and Compact: Easier to handle and install.
Applications:
• Telecommunications: High-speed internet and telephone networks.
• Medical: Endoscopy and imaging devices.
• Industrial: Sensors and equipment monitoring systems.
• Broadcasting: Cable TV and video services.
