Bit

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

A bit is the smallest unit of digital information and has one of two possible values, conventionally 0 or 1.

A bit, short for binary digit, is the smallest unit of information used by computers. It has one of two values: 0 or 1. Eight bits make one byte. section 3.2

Computers compute and communicate in binary. On a network, devices send long sequences of bits across a medium; copper wiring can represent 0 and 1 through different voltage levels. section 3.2

Router-to-switch transmission

When a router sends one byte to a switch, changes in the cable’s electrical voltage represent the byte’s sequence of eight 0s and 1s. section 3.2

Figure 3.1 A router sends 1 byte of data to a switch. Changes in the voltage of the electric signal indicate values of 0 or 1.

Use the diagram to connect a byte of data with voltage changes traveling from a router to a switch. section 3.2

Exam focus:

• Distinguish bits from bytes and recognize that network rates use bits per second. section 3.2 section 3.5

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

How deep it goes

Defines bits and bytes, then illustrates physical voltage signaling without deriving binary conversion methods.

Examples

Uses a router sending one byte to a switch through voltage changes on a cable.

What it assumes

Starts with everyday digital-data terminology and defines binary, bits, and bytes from first principles.

What you can do after

Understand how binary values form bytes and travel as signals between network devices.

How it connects

Connects binary to bytes, network speeds, Ethernet, copper wiring, and voltage signals.

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  Quantum Programming in DepthA bit is a binary digit that represents either zero or one.

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Related concepts

• bytespart of · Bytes are an ordered sequence of values, each conventionally eight bits, used to represent binary data.
• entropymeasures · Entropy is a quantitative measure of uncertainty or dispersion in a probability distribution and, more generally, of disorder in the possible states of a system.
• hardware registerpart of · A hardware register is a small, rapidly accessible storage location within a processor or processing device that holds data, addresses, or control information during execution.
• parity bitincludes · A parity bit is an added binary bit indicating whether the number of 1 bits in associated data is even or odd.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.