How to use PuTTY for a serial connection

Written by adrian grahams Google
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How to use PuTTY for a serial connection
PuTTY lets your computer talk to a connected device via a serial connection. (Getty Thinkstock)

Connecting a computer to another device with a serial cable offers slower connection speeds than modern USB or wireless connections, but it's still sometimes necessary if you need to program or configure settings on an older device. The free PuTTY terminal emulator utility lets you connect your computer to other devices via several communication protocols, including serial connections. Commands typed into the PuTTY window are transmitted directly to the connected device via the computer's serial port and data received from the device through the serial port displays in the PuTTY program window.

Skill level:

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Things you need

  • Serial cable

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  1. 1

    Connect your computer to the other device with a serial cable, also sometimes known as a RS-232 cable, and then power on the connected device. Launch PuTTY on your computer to open the program's default session configuration screen.

  2. 2

    Click to select and enable the "Serial" button in the "Connection type" pane. Type the correct serial port name in the "Serial line" field. On most Windows computers this is "COM1" but, if your computer has more than one serial port, check the port numbering on the rear panel of the PC. You may need to enter "COM2" or "COM3" instead.

  3. 3

    Enter the connection speed, known as the baud rate for serial connections, in the applicable field. The connection speed depends on the capabilities of the connected device so, if in doubt, check the user manual or leave the default "9600" setting in place. Advanced users may also want to enter the number of data bits and stop bits for the serial connection in the relevant fields, but in most cases leave the default values assigned by PuTTY. You can also select your preferred serial parity checking scheme and flow control scheme or retain the defaults.

  4. 4

    Click the "Open" button to start the serial connection session. PuTTY opens a command prompt-style window that you can use to send and receive data between the computer and the connected device.

Tips and warnings

  • PuTTY handles several other network connection protocols, including Raw, Telnet, SSH and Rlogin. Select your preferred session type from the configuration window that appears when you launch the program.

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