Axis Video Server User Manual page 26

Axis video server - Audio (AXIS 241QA/SA only)
26
Full-duplex mode means that you can transmit and receive audio (talk and listen) at the
same time, without having to use any of the controls. This is just like having a telephone
conversation. The only controls you may wish to use are the mute buttons to turn off the
sound, and the sliders, to adjust the input/output volume levels. This mode requires that
the client PC has a sound card with support for full-duplex audio. If your available
bandwidth is 0.2 Mbit/s or less, it is recommended that you use Half-duplex mode instead.
Half-duplex mode also transmits and receives audio in both directions, but only in one
direction at a time. This means that you must select when to receive or transmit audio with
the help of the push-to-talk button. To speak, press and hold the button (check that the
microphone is not muted). When finished speaking, release the button. You will now be
receiving audio from the other end of the connection.
Note that the push-to-talk button is configured from AMC, see AXIS Media Control (AMC),
on page 15. It is also possible to configure the push-to-talk button so that it toggles
between speaking and listening modes. Half-Duplex mode is best if you only have limited
bandwidth available.
When selecting Simplex - AXIS 241QA/SA speaker only mode, the speaker connected to
the AXIS 241QA/SA will play audio, but no audio will be transmitted from the AXIS
241QA/SA to other web clients. This could be used to e.g. provide spoken instructions to a
person seen in a camera. This mode requires you to use the push-to-talk button.
Simplex - AXIS 241QA/SA microphone only mode only transmits audio from the AXIS
241QA/SA to any web clients. It will not receive audio from any other web clients. This
can be used in remote monitoring, web attractions etc., to provide live audio, as well as
video, of a monitored situation.
When using half-duplex, the Send the sound from the active client to all other clients
option transmits the audio signal from the client that is talking to all the other clients.
Audio Input
Audio from an external microphone or a line source can be connected to the Line/Mic In
jack of the AXIS 241QA/SA. The audio source can be set to Microphone or Line. If you are
using a microphone, the input sensitivity can be set to High or Low. See Technical
specifications, on page 66 for the exact maximum levels.
The Enable microphone power option provides DC power for the external microphone. If
you use a small electret condenser microphone such as a clip-on mic or a PC microphone,
this option needs to be enabled.
To use a high impedance dynamic microphone, DC power should not be enabled. DC power
will not harm the microphone, but if you are uncertain, try switching it off and on. DC
power is enabled by default. To use a professional microphone requiring 48V phantom
power, you need an external power supply and must use a balanced-unbalanced converter
(audio transformer) in between.