Serial connection parameters

Connection and serial parameters

Serial communication only works when both sides agree on the same link settings.

• Port: the COM port assigned by the operating system. Re-plugging a device can change it.
• Baud rate: must match the target device. Common values include 9600, 115200, 460800 and 921600.
• Data bits: usually 8.
• Stop bits: usually 1.
• Parity: usually None, but industrial devices may use Even or Odd.
• Flow control: keep it disabled unless the device documentation explicitly requires RTS/CTS or XON/XOFF.
• Append Line Ending: when you use Send, Ctrl+Enter or loop send, the selected CR, LF, CRLF or LFCR bytes are appended to the complete outgoing message.
• Enter Sends: when the receive terminal has focus, pressing Enter immediately sends the selected CR, LF, CRLF or LFCR bytes. It does not change messages sent from the lower send editor.

Custom baud rates are available, but stable high-speed communication still depends on the serial chip, driver, cable quality and target firmware.

Seeing what you send

Two settings decide whether your own traffic appears in the receive view. They are easy to confuse, because both put sent data on screen — but they cover different paths.

Display Send echoes complete messages sent from the send editor: the Send button, Ctrl+Enter and loop send. It also decides whether that outgoing data reaches the log file, so with Display Send off, sent messages are neither shown nor logged.

Local Echo echoes individual keystrokes typed into the receive terminal, one character at a time, at the cursor. It affects the display only and never writes to the log.

Which one you need:

• The device answers your commands but never repeats them: turn on Display Send, so the exchange reads as a conversation instead of half of one.
• The device does not echo what you type, which is common for embedded targets: turn on Local Echo, or you are typing blind.
• The device echoes by itself, such as a login shell: leave Local Echo off, or every character appears twice.

Both start hidden in the Quick Settings panel. Enable them on the Quick Settings page of the settings dialog, or set them directly on its Send page.