Atlona Help Center

KB01108 - Enabling audio to play without a video signal (audio freerun) on HDVS-200



Is it possible to embed audio (via 3.5mm input) without video on the AT-HDVS-200-TX-WP and hear audio via the HDMI or analog audio ports on the AT-HDVS-200-RX?


To pass audio without video, simply enable "free run" via rs232 or the WebGui. Free run audio makes it so that you can send analog audio to the display without VGA or HDMI video present (standalone audio embedding).

To access web interface:

  • Connect a LAN cable to the AT-HDVS-200-TX-WP/200-TX or the AT-HDVS-200-RX (please connect the cable to only one unit at a time).
  • You can see the IP address of the set by accessing the on screen menu from the AT-HDVS-200-RX’s output on your display/projector.
  • Otherwise, perform a network scan and match the MAC address of the AT-HDVS-200-TX/-WP to the ones your network analyzer shows.
  • Web-GUI login = Username: root Password = Atlona (case sensitive)
  • Once logged in, access the Audio settings page and slide the Audio Freerun Status to ON

Please see this article if you do not have access to a DHCP router or want to create your own local network from a PC to the AT-HDVS-200 units

Screenshot of the web interface – Audio settings:


To send RS232 command to the unit enabling FreeRun:

  • Use your favorite RS232 program such as Hterm (Windows) or CoolTerm (Mac)
  • Connect a DB9 to captive screw to the AT-HDVS-200-TX/-WP’s RS232 ports.
  • Connect a USB to Serial cable to your PC and connect this cable to the DB9 to serial cable connected to the HDVS-200-TX/-WP
  • Open your serial program and connect using baud 115200, data length 8, parity 0, stop-bit 1


(Hterm being used to connect to 200-TX/-WP)

  • Set up the “FreeRun on” command to send in ASCII and select “CR” from the Send on enter which represents a carriage return

(Example of the FreeRun command)

  • Press enter on your keyboard to send the command (do not press ASend – this performs a different function)

(“FreeRun on” command was sent and feedback was received confirming settings were changed) 

  • You should see a feedback command get sent (sometimes it’s just a square character). This confirms the setting was properly applied.

Please note: When using audio freerun, a black image is sent out from the HDVS-200-RX. This means, that any device relying on a lack of video to say autoswitch (i.e. AT-UHD-CLSO-612 or AT-UHD-SW-5000ED) will cause it to interpret the black image of the HDVS-200-RX as an active video source. Therefore, you will need to manually switch input either via the front panel of the switch or RS232/telnet. Freerun audio can be enabled/disabled VIA RS232 so it’s possible to set up programming so that audio freerun is toggled when needed.  

Article ID: KB01108 



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