What is Communication
The Foundation of Networking
Communication is the process of transferring information from one point to another.
In human communication, we share information through speech, writing or gestures, all using sound waves, text or body language as our medium.
In technological communication, devices exchange information through electrical (wires), optical (fiber) or radio (wireless) signals, translating digital data into physical energy that can travel across distances.
Basic Communication Model
Every communication system has these elements.
| Component | Role |
|---|---|
| Sender (Transmitter) | Creates and sends the message. |
| Receiver | Accepts and interprets it. |
| Message | The actual information to be sent. |
| Medium (Channel) | The path through which the message travels (wire, air, fiber). |
| Encoder/Decoder | Converts message into signals and back. |
| Noise | Anything that distorts the signal. |
| Feedback | Response from receiver (optional, in two-way systems). |
Signals
| Type | Description | How it works | Example | Used in |
|---|---|---|---|---|
| Analog signal | Continuous wave (varies smoothly) | Continuous wave carries info (amplitude, frequency, phase) | Sound, radio | Old telephones, radio, TV |
| Digital signal | Discrete 0s and 1s (on/off) | Discrete bits; noise-resistant; easily encrypted and stored | Computer data | Computers, Internet, VoIP |
Analog signals vary continuously (like a sine wave), while digital signals have discrete states (on/off, high/low).
The move from analog → digital made modern networking possible because digital data can be compressed, corrected, and routed easily.
Encoding & Modulation
To send information over a medium, it must be converted into a signal:
- Encoding transforms data into a signal format suitable for the medium (e.g., voltage levels, light pulses).
- Modulation changes properties of a carrier wave to represent data (AM/FM for analog, QAM for digital).
When your phone sends data over Wi-Fi or 5G, it modulates radio waves to carry information.
Communication Mediums
| Medium | Used in | Characteristic |
|---|---|---|
| Copper cables (electrical) | Ethernet, telephone | Cheap, short range |
| Optical fiber (light) | Long-distance Internet backbone | Very high speed, low loss |
| Wireless (radio, microwave) | Wi-Fi, 4G/5G, satellite | Mobility, but interference-prone |
Types of Communication
| Type | Description | Example |
|---|---|---|
| Simplex | One way only | Monitor displaying output |
| Half-duplex | Two way, but one at a time | Walkie-talkie |
| Full-duplex | Two way simultaneously | Phone call, Internet data |
Synchronization
How do sender and receiver stay "in rhythm"?
Synchronous communication: continuous stream with a shared clock (Ethernet, video calls).
Asynchronous communication: independent timing, with start/stop markers (serial ports, email).
Key Performance Terms
| Term | Meaning |
|---|---|
| Bandwidth | Maximum amount of data that can be transmitted per second (e.g., 100 Mbps). |
| Latency | Time delay for data to reach destination. |
| Throughput | Actual data rate achieved. |
| Noise | Unwanted interference that distorts signals. |
| Error rate | Percentage of bits that get corrupted. |
Every medium and technology balances these trade-offs.
What's Next?
This article covered the fundamentals of communication that apply to all systems—human, technological, analog, and digital.
To understand how computers specifically exchange digital information, read about Data Communication, which focuses on bits, bytes, protocols, and computer networking.
Communication is the universal concept.
Data communication is its application to computers.