Page 164 - PYTHON-12

8.8 DATA COMMUNICATION TERMINOLOGIES

1. Channel: A channel is a communication path through which the data is transmitted from the
sender device to the receiver device.
2. Baud: The number of changes in a signal per second is known as baud. It is the measuring
unit of the data transfer rate. Technically, baud refers to a number of discrete signal elements
transmitted per second. 1 baud represents only 1 signal change per second and is equivalent to
1 bit per second.
3. Bandwidth: The amount of data that can be passed along a communication channel in a given
period of time (1 second) is termed as bandwidth. The measuring unit is hertz (Hz), where 103
Hz = 1 Kilo Hertz (KHz), 103 KHz = 1 Mega Hertz (MHz).

4. Data and Signals: Information that is stored within computer systems and transferred over
a computer network can be divided into two categories—data and signals. Data are entities
that are stored in the form of 0’s and 1’s, which convey some special meaning to the computer
system. When this data is transmitted from one place to another, it is converted into signal.
Signals are the electric or electromagnetic encoding of data and are used to transmit data.
5. Communication/Transmission Media: It is a means of communication or access (lines
of communication) set up between two organizations to exchange data/information.
Communication media is the way of transmitting the signal from one place to another.
Communication media is also known as transmission media. It plays an important role in
sending and receiving of data to and from the sender and receiver.
6. Data Transfer Rate: It is the amount of data transferred in one direction over a link divided
by the time taken to transfer it in bits per second (bps). The various measuring units are Both
bits per second and bytes second have been abbreviated as (bps). or baud, kilobits per second
(kBps), megabits per second (mBps), gigabits per second (gBps), terabits per second (tBps.)

8.9 NETWORK DEVICES

1. Modem: A MODEM (Modulator DEModulator) is an electronic device that enables a
computer to transmit data over telephone lines. It is a device used to convert digital signals
into analog signals and vice versa. There are two types of modems, namely internal modem
and external modem.
2. RJ-45 Connector: RJ-45 is a standard type of connector for network cables. The RJ-45 (Registered
Jack) connectors are the plug-in devices used in networking and telecommunications
applications. They are used primarily for connecting LANs, particularly Ethernet.
Computer Science with Python–XII 8.10 3. Ethernet Card: It is a hardware device that helps in the connection of nodes within a
CTM: RJ-45 is a short term for Registered Jack-45. It is an eight-wire connector used to connect computers
on LANs, especially Ethernets.

network. Ethernet card is also known as a network card, network adapter or NIC (network
interface card). It is a card that allows computers to communicate over a computer network.
On Ethernet card, a physical address of each communicating computer is mentioned.
Physical address is known as MAC address.