START and STOP bits are sent in ______ mode of transmission.

The correct answer is Asynchronous.

Key Points

• Asynchronous Transmission,
• It is also known as character-based transmission and conveys data in the form of individual bytes or characters.
• This mode of transmission operates as a half-duplex communication method, meaning that data can flow in one direction at a time.
• It employs the inclusion of start and stop bits along with the data to facilitate proper framing. 
  • START Bit: The transmission begins with the transmission of a START bit, which is always a logic 0 (low voltage level).
    • This START bit alerts the receiving device that data is about to be transmitted, and it helps the receiver synchronize its internal clock with the sender's clock.
  • Data Bits: Following the START bit, the actual data bits (typically 8 bits, but they can vary) are sent one by one.
    • These represent the actual information being transmitted, such as a character or a piece of data.
  • STOP Bit(s): After the data bits, one or more STOP bits are sent.
    • The STOP bit(s) indicate the end of the data character.
    • In most cases, one or two STOP bits are used, depending on the system configuration.
    • These STOP bits are always logic 1 (high voltage level).

Additional Information

• Synchronous Transmission,
  • It is characterized by the transfer of data in the form of blocks or frames, and operates in full-duplex mode, enabling simultaneous two-way communication between sender and receiver.
  • This mode mandates precise synchronization between the communicating devices.
  • Synchronous transmission maintains a continuous flow of data without any gaps.
  • It is recognized for its efficiency and reliability, making it the preferred choice for transferring substantial volumes of data.