How to connect to a serial console in PuTTY

A serial console provides direct, out-of-band access to a device for initial configuration, troubleshooting, and recovery when network access is unavailable. Connecting with PuTTY on Windows 11 makes it possible to interact with the device’s console port using a familiar GUI.

Serial consoles use a local serial interface exposed by Windows as a COM port (built-in UART, USB-to-serial adapter, or a vendor console cable). PuTTY opens that port and exchanges raw text with the device using the selected communication parameters such as Speed (baud), Data bits, Parity, Stop bits, and Flow control.

Console settings must match the device, or output appears garbled or stays blank. Serial access is also not encrypted, so physical access to the cable and port equals privileged access; keep consoles secured and disconnect when finished.

Related: How to increase the scrollback buffer in PuTTY
Related: How to save session settings in PuTTY

Steps to connect to a serial console in PuTTY:

  1. Connect a USB-to-serial adapter to the PC when no physical serial port is available.
  2. Connect the console cable to the device’s console or serial port.
  3. Open Device Manager in Windows 11.
  4. Expand Ports (COM & LPT) in Device Manager.
  5. Note the COM port number for the serial adapter.
  6. Launch PuTTY.
  7. Select Serial under Connection type.
  8. Enter the COM port (for example, COM3) in Serial line.
  9. Enter the device’s Speed (baud) value (for example, 9600) in Speed.

    Common console speeds are 9600 and 115200.

  10. Open Connection → Serial in the left category tree.
  11. Set Data bits to 8.
  12. Set Stop bits to 1.
  13. Set Parity to None.
  14. Set Flow control to None unless the device documentation specifies otherwise.

    A mismatched Flow control setting can block typing or prevent any output.

  15. Enter a name in Saved Sessions under Session.
  16. Click Save to store the serial settings.

    Saving the profile keeps serial settings ready for the next connection.

  17. Click Open to start the serial session.

    Serial sessions are unencrypted; treat console access like a root password on a cable.

  18. Confirm console access by checking for a login prompt or boot messages.

    Garbled characters usually mean the wrong Speed (baud), while a blank screen often indicates the wrong COM port or Flow control setting.

  19. Press Enter to refresh the console when the screen is idle.

    Use Special Command → Break only when interrupting the bootloader is required.