Which of the following best describes full duplex?

Table of Contents Show

Comparison Chart
Half Duplex
Full Duplex
Key Differences of the Three Transmission Modes
Further Reading
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There are three modes of transmission, namely: simplex, half-duplex, and full-duplex. The transmission mode defines the direction of signal flow between two connected devices.

The primary difference between the three modes of transmission is that in a simplex mode of transmission the communication is unidirectional, or one-way; whereas in the half-duplex mode of transmission the communication is two-directional, but the channel is interchangeably used by both of the connected devices. On the other hand, in the full-duplex mode of transmission, the communication is bi-directional or two-way, and the channel is used by both of the connected devices simultaneously.

Comparison Chart

Basis for Comparison	Simplex	Half Duplex	Full Duplex
Direction of Communication	Unidirectional	Two-directional, one at a time	Two-directional, simultaneously
Send / Receive	The sender can only send data	The sender can send and receive data, but one a time	The sender can send and receive data simultaneously
Performance	Worst performing mode of transmission	Better than Simplex	Best performing mode of transmission
Example	Keyboard and monitor	Walkie-talkie	Telephone

Simplex

In simplex transmission mode, the communication between sender and receiver occurs in only one direction. The sender can only send the data, and the receiver can only receive the data. The receiver cannot reply to the sender.

Simplex transmission can be thought of as a one-way road in which the traffic travels only in one direction—no vehicle coming from the opposite direction is allowed to drive through.

To take a keyboard/monitor relationship as an example, the keyboard can only send the input to the monitor, and the monitor can only receive the input and display it on the screen. The monitor cannot reply, or send any feedback, to the keyboard.

Half Duplex

The communication between sender and receiver occurs in both directions in half-duplex transmission, but only one at a time. The sender and receiver can both send and receive the information, but only one is allowed to send at any given time. Half-duplex is still considered a one-way road, in which a vehicle travelling in the opposite direction of the traffic has to wait till the road is empty before it can pass through.

For example, in walkie-talkies, the speakers at both ends can speak, but they have to speak one by one. They cannot speak simultaneously.

Full Duplex

In full-duplex transmission mode, the communication between sender and receiver can occur simultaneously. The sender and receiver can both transmit and receive at the same time. The full-duplex transmission mode is like a two-way road, in which traffic can flow in both directions at the same time.

For example, in a telephone conversation, two people communicate, and both are free to speak and listen at the same time.

Key Differences of the Three Transmission Modes

In simplex mode, the signal is sent in one direction. In half duplex mode, the signal is sent in both directions, but one at a time. In full duplex mode, the signal is sent in both directions at the same time.
In simplex mode, only one device can transmit the signal. In half duplex mode, both devices can transmit the signal, but one at a time. In full duplex mode, both devices can transmit the signal at the same time.
Full duplex performs better than half duplex, and half duplex in turn performs better than simplex.
Simplex: The keyboard sends the command to the monitor. The monitor cannot reply to the keyboard.
Half duplex: Using a walkie-talkie, both speakers can communicate, but they have to take turns.
Full duplex: Using a telephone, both speakers can communicate at the same time.
The full duplex transmission mode offers the best performance among the three, on account of the fact that it maximises the amount of bandwidth available.

Cards Return to Set Details

Term

Which of the following describes the arrangement of network cabling between devices?

a. logical topology

b. networking topology

c. physical topology

d. media access method

Definition

Term

Which of the following is an advantage of star topology?

a. allows faster technologies than bus

b. requires less cabling than bus

c. centralised monitoring of network traffic

d. no single point of failure

Definition

Term

Which topology is likely to be deployed in a WAn where theres a centra office and three branch offices and you want all traffic from the branch offices to go through the central office network?

a. Ring

b. PMP (point to multipoint)

c. Mesh

d. Point to point

Definition

Term

Which technology is likely to implenented as a point to point physical toppology?

a. wifi infrastructure mode

b. FDDI

c. Ethernet

d. Wireless bridge

Definition

Term

Which of the following describes a hub-based ethernet network?

a. physical bus

b. logical bus

c. physical switching

d. logical star

Definition

Term

You're configuring a WLAN in a long narrow ballroom. Only place for the AP is at the far end of the room - which type of antenna should you use?

a. Unidirectional

b. bidirectional

c. omni directional

d. semidirectional

Definition

Term

Which best describes a typical wireless LAN?

a. logical ring topology

b. logical switching topology

c. logical bus topology

d. logical star topology

Definition

Term

Which f the following is a characteristic of a switched logical topology?

a. uses a physical bus topology

b. creates dynamic connections

c. sometimes called a shared media topology

d. uses a physical star topology

Definition

Term

Which of the following is a characteristic of unshielded twisted pair cabling (choose all that apply)?

a. consists of four wires

b. commonly used in physical bus topologies

c. has a distance limitation of 100m

d. susceptible to electrical interference

Definition

Term

Which of the following is a characteristic of fiber optic cabling?

a. can be used in electrically noisy environments

b. Requires only a single strand of fiber for network connections

c. Carries data over longer distances than UTP

d. Lower bandwidth capability

Definition

Term

Which topology most likely used coaxial cabling?

a. physical star

b. logical ring

c. physical bus

d. logical switching

Definition

Term

Which of the following is true of a MAC address?

a. a MAC address of all bunary 1s in the source address indicates a broadcast frame

b. Sometimes called the logical address

c. destination address of 12 hexadecimal Fs is broadcast

d. Composed of 12 bits

Definition

Term

Which type of wifi signal interference is most likely caused by leaves on trees?

a. Diffraction

b. Reflection

c. Refraction

d. Scattering

Definition

Term

Which of the following is a field of the most common ethernet frame type (choose all that apply)?

a. ARP trailer

b. FCS

c. Destination MAC address

d. data

e. MAC type

Definition

Term

Which access method uses a 'listen before sending' strategy?

a. token passing

b. CSMA/CD

c. token bus

d. polling

Definition

Term

Which of the following is true of full duplex ethernet (choose all that apply)?

a. stations can transmit and receive but not at the same time

b. collision detection is turned off

c. its possible only with switches

d. allows a physical bus to operate much faster

Definition

Term

Which of the following is defined by the extent to which signals in an ethernet bus topology network are propagated?

a. physical domain

b. collision domain

c. broadcast domain

d. logical domain

Definition

Term

Which of the following is considered a property of ethernet?

a. scalable

b. best effort delivery system

c. guaranteed delivery system

d. obsolete technology

Definition

Term

Which of the following is true of IEE 802.3an?

a. requires two airs of wires

b. uses cat 5 or higher cabling

c. currently best for desktop computers

d. operates only in full duplex mode

Definition

Term

Which of the following is a feature of 100BaseFX (choose all that apply)?

a. Often used as backbone cabling

b. best when only short cable runs are needed

c. fastest of the ethernet standards

d. uses two strands of fiber

Definition

Term

Which wifi standard can provide highest bandwidth?

a. 802.11ac

b. 802.11b

c. 802.11n

d. 802.11g

Definition

Term

Which of the following is true about infrastructure mode in wireless networks?

a. best used for temp networks

b. uses a central device

c. resembles a physical bus and logical ring

d. most like a logical bus and physical star

Definition

Term

How many channels can be used on an 802.11b network in N. America?

a. 7

b. 9

c. 11

d. 13

Definition

Term

Which access method does wifi use?

a. CSMA/CD

b. TOken bus

c. Demand priority

d. CSMA/CA - carrier sense multiple access / collision avoidance

Definition

Term

Which wifi standard uses beamforming to allow an AP to send data to mulitple devices simultaneously?

a. 802.11ac

b. 802.11n

c. 802.11a

d. 802.11g

Definition

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