USB vs UART vs RS232 – Difference and Comparison

What is USB?

A USB (Universal Serial Bus) connects a computer or device to peripheral devices such as printers, digital cameras, and external hard drives. USB connections are widely used for data transfer and charging devices and are the most common computer connection.

USB connections are easy to set up and use and provide a fast and reliable data transfer rate.

USB connections are available in two different sizes: USB Type A and USB Type B. USB Type A is the larger of the two and is used for connecting to peripheral devices. In contrast, USB Type B is used for connecting to the computer itself. USB connections come at different speeds, with USB 2.0 being the most common. 

USB connections are an easy and reliable way to connect devices to a computer and are widely used for data transfer, charging devices, and more.

What is UART?

Universal Asynchronous Receiver/Transmitter (UART) is a serial communication protocol used for data transfer between two devices. It is a full-duplex, asynchronous communication protocol that allows data to be transmitted and received simultaneously.

UARTs are widely used in embedded systems, microprocessors, and other digital systems to connect devices and send and receive data over a single wire, as a serial port.

UARTs establish communication between two devices, such as a computer and a modem or a CPU and a peripheral. UARTs are used to connect a computer to a network.

UARTs help transfer data over short distances, such as between two boards in an embedded system, and are also used in wireless technologies. UARTs are used in many applications, such as automotive telematics, home automation, and industrial automation.

What is RS232?

RS232 is a standard for serial communication used to send and receive data between two devices. It is a serial communication protocol for data transfer between two devices, such as a computer and a modem. RS232 is a reasonably old standard, but it is still widely used in many applications.

RS232 uses a standard 9-pin connector which is connected to the serial port of a computer. The RS232 protocol defines how data is sent as bit-serialized data.

RS232 is a reliable and robust protocol that is easy to use and configure. It is used for both short and long-distance data transfer. It is also very reliable and robust, making it suitable for industrial applications.

Overall, RS232 is an essential protocol for data transfer between two devices. It is reliable, robust, and easy to use, making it suitable for many applications.

Difference Between USB, UART, and RS232

  1. USB is primarily used for computer-to-peripheral communication, while UART and RS232 are used for serial communication between two devices. 
  2. USB is a serial bus, while UART and RS232 are asynchronous serial communication protocols.
  3. UART is mainly used for low-speed communication, while USB and RS232 are mainly used for high-speed communication.
  4. UART is used in embedded systems, while USB and RS232 are used in PCs and laptops.
  5. RS232 is a serial communication interface, while UART and USB are parallel.
  6. RS232 requires a null modem cable for communication, while UART and USB require a USB cable.

Comparison Between USB, UART, and RS232

Parameters of comparisonUSBUARTRS232
Data transfer rateUp to 480 MbpsUp to 4.8 MbpsUp to 20 Kbps
Number of pins489
Power sourceSelf-powered or bus poweredSelf-poweredSelf-powered
Wire connectionIt uses a 4-wire connectionIt uses a 3-wire connectionIt uses a 9-wire connection
Usageused for external peripheral devicesused for serial data transmissionused for serial data transmission and modem control.


  1. USB System Architecture – Don Anderson – Google Books