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RTS Request to send

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In computer networking and telecommunications, RTS (Request to Send) is a control signal used in data transmission protocols, particularly in serial communication interfaces. It is commonly employed in RTS/CTS (Request to Send/Clear to Send) handshaking, which is a flow control mechanism used to coordinate the transmission of data between two devices.

The RTS signal is typically sent by the transmitting device to the receiving device to request permission to send data. When the transmitting device wants to transmit data, it asserts the RTS line to a logic high (usually +3 to +15 volts) level. The RTS signal is then received by the receiving device, indicating that the transmitting device is ready to send data.

The RTS/CTS handshaking mechanism is used to prevent data overflow or collisions in situations where the receiving device might not be ready to receive data. Here's a step-by-step explanation of how the RTS/CTS handshaking works:

  1. The transmitting device checks the CTS (Clear to Send) line status before sending data. The CTS line is controlled by the receiving device.
  2. If the CTS line is asserted to a logic high level, it indicates that the receiving device is ready to receive data.
  3. If the CTS line is deasserted or held at a logic low level, it indicates that the receiving device is not ready to receive data.
  4. Before transmitting data, the transmitting device asserts the RTS line to a logic high level, sending a Request to Send signal.
  5. The receiving device receives the RTS signal and interprets it as a request for permission to send data.
  6. If the receiving device is ready to receive data, it responds by asserting the CTS line to a logic high level, indicating Clear to Send.
  7. Upon receiving the CTS signal, the transmitting device knows that it has permission to start transmitting data.
  8. The transmitting device can then start sending the data.
  9. Once the transmission is complete, the transmitting device deasserts the RTS line to a logic low level, indicating that it has finished sending data.
  10. The receiving device, upon detecting the RTS line deasserted, can prepare to receive the next set of data.

By using the RTS/CTS handshaking mechanism, the transmitting device can avoid sending data when the receiving device is not ready, preventing data loss, buffer overflow, or collisions. It helps to regulate the flow of data between devices and ensures efficient and reliable communication.