Atlona Help Center

KB01177 - How to use Hterm (free serial program)

SKU:  Any Atlona device with a serial (RS232) connection

Subject: How to use Hterm


  • Hterm is a free serial program which can be downloaded here.
  • This program allows you to communicate with Atlona devices using their RS232 ports.
  • Most newer Atlona devices have a captive screw serial port () and older units have a dedicated DB9 port ()
  • You can connect to these ports using a USB to serial cable such as this TRENDnet USB to Serial cable. You may also need a null modem adapter or a gender changer adapter.
  • For devices with captive screw RS232 port, you will need to create a DB9 to bare wire cable. An article for this process can be found here.
  • After obtaining the necessary equipment and making the DB9 cable, you can use Hterm to communicate with the device. The steps for this are below:
  1. Download Hterm
  2. Open Hterm
  3. Initiate your connection by clicking the connect button in the top left corner:

Please note, you will need to have a comm port already selected (HTerm will try to automatically find the comm port). If you don’t have any comm ports showing up, please check your USB to RS232 cable and try another USB port. You can also check port settings and port #’s in Device Manager:

  1. After clicking connect, check that you see the following message in the bottom right corner of the software:. This confirms a connection has been established.
  2. Next, you are ready to enter RS232 commands. Please note, Hterm only supports commands sent in either ASCII or HEX but does not support both at the same time. If you are attempting to send a combination of ASCII and HEX, please convert your ASCII command to HEX using a converter such as this one.
  3. Please enter commands into the “Input controls section” and confirm the following is selected:
  4. You can test the connection by sending the command “Type” which should respond back with the model number of the device you’re communicating with. The command will be entered here:
  5. The response, after sending the command will be:


This confirms the connection has been established and you can now send other commands. A full list of commands is found in the respective device's users manuals.





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