What is Error Detection?

When data is shared from one computer to another computer, the system does not protect whether the information received by the computer is actually to the data transmitted by another computer. An error is when the message received at the receiver end is not interchangeable with the message sent.

Types of Errors

Following are the types of errors −

Single-Bit Error

These errors occur when only a single bit in a data packet is changed from 1 to 0 or 0 to 1. These types of errors are most likely to happen in the parallel transmission of data.

Suppose a block of data is sent over the network

00011101                ----------------→                        00001101

Block Sent                                                     Block received

When this block is received, the fourth bit starting from MSB is changed from1 to 0. Thus single-bit error has occurred.

Burst Error

Burst error occurs when 2 or more bits in the data packet have changed from 1 to 0 or 0 to 1. These types of errors are most likely to occur in serial data transmission. For example, consider the following block of data when sent across the network.

00110011                ----------------→                        11000011

Block Sent                                                     Block received

Here in this block, starting from MSB, 4 bits have changed from 1 to 0 and 0 to 1. Thus the length of burst error is 4 since 4 bits have been changed.

Source of Errors in Data Communication

• The length between the sender and receiver is the primary factor of error. With the increase of distance, there is a decrease in the power signal the data gets attenuated. The larger the distance, the more noise, interference that alters the data, and we get an error.

• The change in original data may be due to a delay during transmission, due to which the data gets distorted, called delay distortion.

• Echo is the signal's distorted effect when the sender's signal comes back due to leakage or not properly ending of the wires then the sender hears his voice called echo.

• If we use unshielded wires or any problem in the wires gets the signal distorted, and there is a faint voice of any other party. This is called cross talk.

• Due to high amplitude, unwanted signals distorted the original signal. This is called impulse noise.

• If the carrier frequency of sender and receiver ends are not precisely saved, then the transmitted signal suffers a change in frequency called frequency shift.

• Due to low-frequency ripples in power supplies the signal gets distorted.

• No of different transmission components: More the components involved in the communication network, the more the chances of occurring in transmitting signals.

• Atmospheric changes: The reason for error can be atmosphere changes like snow, rain, fog.

• Due to varying physical conditions, the chances of occurring error is more than in normal conditions.