Instruction manual
AXIS 2400+/2401+ Admin Manual The AXIS 2191 Audio Module
 33 
Simplex - Talk
Simplex - Talk mode means that only the web-client end of the connection can transmit audio 
(that is, to the AXIS 2191). This can be used to e.g. provide spoken instructions to a person seen 
in the image from the video server. This mode also requires the Push-to-Talk button.
Simplex - Listen
Simplex - Listen mode can only receive audio from the AXIS 2191 to the web-client. This can 
be used in remote monitoring, web attractions etc., to provide live audio, as well as video, of a 
monitored situation.
Troubleshooting the Audio Module
Note: If you still have a problem after reading this information, contact your reseller, or visit 
www.axis.com and check the support section for Axis camera and video products. 
Symptoms Possible causes Remedial actions
No audio controls below 
image.
The AXIS 2191 is not selected 
for use on COM2.
In the server’s administration tools, click on the icon for COM2 and 
set the purpose to AXIS 2191 Audio Module.
Wrong video server firmware. If the AXIS 2191 does not appear as a purpose for COM2 in the 
Administration Tools, the server does not have the correct firmware 
and must be upgraded. See Updating the Firmware, on page 41.
No sound from the AXIS 
2191 or from a PC trying to 
access a web page 
containing audio content.
Incorrect settings or faulty 
connections.
Check that: 
• sound card, speakers and microphone are connected
• the Mute button is not pressed
• the Int/Ext switch for the input is in the correct position
• the input and output levels are correct
• all cabling is connected and all power switches are ON
No audio signal from PC to 
the AXIS 2191 when passing 
a proxy server. 
The Post Content Length set 
in the proxy server is too low. 
Set the value of the Post Content Length in your proxy server to 1MB 
or more. You may need to contact your system administrator to do 
this.
No full-duplex function. Incorrect configuration. Check the setting in the server’s administration tools. 
Sound card does not support 
full-duplex.
For information on how to check if your sound card supports 
full-duplex, please visit www.axis.com and see the support section for 
Axis camera and video products.
Poor performance. Too many users/clients. Try limiting the number of clients allowed to connect.
Low bandwidth. Reduce the available bandwidth by changing to a lower setting in the 
Available Bandwidth selector. Setting a lower bandwidth will reduce 
any break-up in the sound, but will also increase the transmission 
delay. 
If running in Full-Duplex mode, try switching to Half-Duplex mode.
Whining or screeching sound 
from speakers (feedback).
Poor positioning of speakers 
and/or microphone.
Relocate the speakers or microphone so that they do not point 
towards each other, and/or lower the volume.
Poor sound on headphones. Incorrect connection. Headphones can only be used by connecting them to Speaker-Out on 
the terminal connector.
The Power indicator LED is 
not constantly lit. 
Faulty power supply. Verify that you are using an AXIS PS-D power supply.
The AXIS 2191 works locally, 
but not externally.
Firewall protection. Check the Internet firewall with your system administrator.
Default routers required. Check if you need to configure the default router settings.










