Why Data Received via Serial Port Appears as Garbage Text

In the complex environment of Industrial Internet of Things (IIoT), serial communication serves as a fundamental method for data transmission, and its stability and accuracy are crucial for the overall system operation. However, in practical applications, we sometimes encounter situations where the data received via serial port appears as garbage text. The following are some professional explanations for this phenomenon:

I. Mismatched Communication Parameters

In serial communication, parameters such as baud rate, data bits, stop bits, and parity bits are crucial for ensuring the correct transmission of data. If the settings for these parameters differ between the sender and receiver, it can lead to misalignment or errors in the data during transmission, resulting in garbage text at the receiving end.

1. Mismatched baud rate: Baud rate represents the data transmission speed in serial communication. If the baud rates set by the sender and receiver are inconsistent, it can cause temporal misalignment in the data during transmission, leading to garbled text.
2. Incorrect settings for data bits and stop bits: Data bits represent the number of data bits transmitted each time, while stop bits indicate the end of data transmission. If the settings for data bits or stop bits differ between the sender and receiver, it can lead to truncation or confusion of data during transmission, resulting in garbage text.

II. Hardware Issues

Apart from mismatched communication parameters, hardware issues can also cause the data received via serial port to appear as garbage text.

1. Line connection problems: Serial communication relies on stable line connections. If there are issues such as broken lines, short circuits, or poor contact, it can lead to data loss or damage during transmission, resulting in garbage text.
2. Level conversion issues: Different serial devices may use different level standards (such as TTL, RS-232, RS-485, etc.). If devices with different level standards are directly connected without level conversion, it can cause errors in data transmission, leading to garbage text.

III. Software Issues

In addition to hardware and communication parameters, software issues can also result in garbage text being received via serial port.

1. Serial port driver problems: The serial port driver is crucial software for controlling serial communication. Defects or misconfigurations in the driver can lead to issues such as garbled text in the received data.
2. Inconsistent transmission protocols: When using serial ports for data transmission, the sender and receiver must follow the same transmission protocol. Inconsistencies or misunderstandings in the protocol can lead to errors in data transmission, resulting in garbage text.

IV. Interference and Noise

In industrial environments, electromagnetic interference and noise are common. These can enter the data transmission system through serial lines, causing errors or damage to the data during transmission, resulting in garbage text.

V. Solutions

To address the possible causes of garbage text received via serial port, we can take the following measures:

1. Check for consistent communication parameters: Ensure that the baud rate, data bits, stop bits, and parity bits set by the sender and receiver are identical.
2. Check hardware connections and level conversion: Ensure that serial line connections are stable and reliable, and use the correct level conversion devices or chips for connections.
3. Update or repair serial port drivers: Ensure that the serial port drivers are up-to-date and configured correctly.
4. Check for consistent transmission protocols: Ensure that the sender and receiver follow the same transmission protocol and understand its specifications correctly.
5. Adopt anti-interference measures: In industrial environments, adopt anti-interference measures (such as shielded cables, filters, etc.) to reduce the impact of electromagnetic interference and noise on data transmission.