What Are Communication Protocols? Types, Working, and Applications

Introduction

Communication protocols play a vital role in the digital world by defining rules that allow devices and systems to exchange data reliably. Organizations such as the World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF) develop these protocols to ensure global interoperability, security, and efficiency. For example, when HTTP is converted to HTTPS, communication protocols become essential because Secure Socket Layer (SSL) certificates are required to protect data transmission. As technology evolves rapidly, modern networks rely on a wide range of communication protocols. In the Internet of Things (IoT), communication protocols enable diverse devices to connect and exchange data across global networks using the latest evolving standards.

What Are Communication Protocols?

Communication protocols define the format, timing, sequence, and error control of digital messages exchanged between devices. Their primary purpose is to enable reliable data transfer between computer systems and electronic devices. These protocols manage signaling, authentication, error detection, and error correction. They define both syntax and semantics and support analog as well as digital communication.

Basic Definitions

Protocol: A set of rules and regulations.

Communication: Exchange of information between two systems using a medium.

Communication Protocol: A set of rules that allows electronic devices to connect and exchange data with each other.

Why Are Communication Protocols Important?

Communication protocols enable devices to transmit analog signals, digital signals, files, and processed data efficiently. They ensure that data is delivered accurately from source to destination. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are two of the most important networking protocols.

Types of Communication Protocols

Communication protocols are broadly classified into two types:

• Inter System Protocol
• Intra System Protocol

Inter System Protocol

Inter-system protocols are used for communication between two different devices, such as a computer and a microcontroller. This communication is performed using inter-bus systems.

Inter System Protocols

• UART Protocol
• USART Protocol
• USB Protocol

UART Protocol

UART (Universal Asynchronous Receiver and Transmitter) is a serial communication protocol that uses two data lines: RX and TX. Data is transmitted bit by bit without clock pulses. UART is a half-duplex protocol, meaning data transmission and reception cannot occur simultaneously. It typically uses one start bit, eight data bits, and one stop bit.

USART Protocol

USART (Universal Synchronous and Asynchronous Receiver and Transmitter) supports both synchronous and asynchronous communication. It is a full-duplex protocol using RX and TX lines along with clock pulses.

USB Protocol

USB (Universal Serial Bus) is a serial two-wire communication protocol using D+ and D− lines. It is widely used to connect peripherals to computers and controllers. USB supports multiple speed modes ranging from low speed to high speed and allows devices to transfer data without continuous host requests.

Intra System Protocol

Intra-system protocols enable communication between devices located on the same circuit board. They reduce circuit complexity, power consumption, and cost while improving data security.

Intra System Protocols

• I2C Protocol
• SPI Protocol
• CAN Protocol

I2C Protocol

I2C (Inter-Integrated Circuit) uses two wires: SDA (data line) and SCL (clock line). It follows a master-slave communication model where each slave device has a unique address. Data is transmitted in 8-bit frames with acknowledgment bits. Philips Semiconductors originally developed the I2C protocol.

SPI Protocol

SPI (Serial Peripheral Interface) is a high-speed full-duplex protocol developed by Motorola. It uses four wires: MOSI, MISO, SCLK, and SS. The master selects one slave device at a time and initiates communication. The word size is flexible and not limited to 8 bits.

CAN Protocol

CAN (Controller Area Network) is a robust serial communication protocol developed by Robert Bosch in 1985. It uses two wires: CAN High and CAN Low. CAN is widely used in automotive and industrial control systems.

Communication Protocols in IoT

IoT communication protocols ensure secure and efficient data exchange between connected devices. These protocols may operate on IP-based or non-IP-based networks. Non-IP protocols such as Bluetooth consume less power, while IP-based protocols offer long-range communication.

Top IoT Communication Protocols

• WiFi
• Bluetooth
• Zigbee
• LoRaWAN
• SigFox
• MQTT
• NFC
• Z-Wave
• OPC-UA
• Cellular

Data Communication Protocols

Data communication protocols enable devices and networks to understand and interpret data correctly. They define formatting, transmission rules, and error checking.

PLC Communication Protocols

PLC communication protocols are used in industrial automation systems. They depend on baud rate, network size, and number of nodes.

Common PLC Protocols

• Modbus
• Profibus
• EtherCAT
• DeviceNet
• ControlNet
• ProfiNet
• CANopen
• RS-232, RS-422, RS-485

Communication Protocols in Cloud Computing

Cloud platforms commonly use HTTP and MQTT protocols. MQTT is widely used in machine-to-machine communication, while HTTP operates as a connectionless protocol. Cloud communication protocols support login management, data storage, networking, encryption, and authentication.

Common Cloud Communication Protocols

• MQTT
• HTTP
• Secure Shell (SSH)
• IGMP
• Gossip Protocol
• Media Transfer Protocol (MTP)

Conclusion

Communication protocols form the backbone of modern digital communication. They enable secure, reliable, and efficient data exchange across devices, networks, cloud platforms, and IoT systems.