Extended sound settings
From Univention Wiki
This article explains how the sound output on Thin Clients with UCD is configured.
The installation is described in the UCS Thin Client Services manual. Detailed instructions on how to configure the Pulseaudio server with TCS is described in the [[Support Database | Support and Knowledge Base (SDB)].
Currently TCS doesn't support audio input (e.g. microphones). They cannot be used.
Changing the volume
There are different ways to change the volume for sessions.
To reconfigure the default initial volume, change the UCR variable to a value between 0 and 100:
By default, the value is set to 40 % of the Thin Client's maximum output.
Using the commandline tool alsamixer, the volume can be changed as well. The changes are for the running session only and will be overwritten when the user logs in again.
Since UCS 3.0, the KDE tool KMix is available to change the volume. The program can be started from the K-menu and places an icon in the systray. In addition to quick accessing the general volume setting, KMix also offers the possibility to change the volume for running programs individually.
The settings are not saved and will be overwritten when the user logs in again.
Sound during RDP and Citrix sessions
When, next to the UCD terminal server, a Microsoft Windows terminalserver and Citrix terminalserver are used, the sound output doesn't work with a running Pulseaudio server.
Deactivating Pulseaudio using a UCR policy
To deactivate the Pulseaudio server using a UCR policy, the UCR variable
must be set to None. After rebooting the Thin Client, sound output works in RDP and Citrix sessions. However, there will be no sound output in UCD sessions.
Activating sound output on a Windows Terminalserver
Sound output must be activated on a Microsoft Windows 2008 [R2] Terminalserver. This is done by navigating to Administrative services -> Configure terminal services and selecting RDP-TCP connections. In the section Deactive ... on the tab Client settings, the entry Audio must not be ticked.
Playing audio files
Using the commandline tool aplay
A sound file can be played on the commandline by using the command aplay. When using the flag -v, additional information regarding playback and the ALSA environment are displayed. For testing purposes, the sound files located in
can be used.
UCD 3.0 ships applications for audio and video playback. They can be found in the K-Menu --> Applications --> Multimedia. Since these applications lack verbose output of information they're not suitable for diagnosing problems, but provide a user-friendly interface for playback.
Playback while booting
It is possible to play sound files while the Thin Client is booting. For this to work, the Pulseaudio server must be activated and the sound file, that is to be played, must be specified with a UCR variable. It is sufficient to create the UCR variable
and set aplay with the soundfile that is to be played:
Hint: Please note that the soundfile is located in
on the terminal server.
amixer startup variable
It is possible, depending on the used sound driver, to (de-)activate channels while booting the system as well as changing the volume and other settings. The settings are changed by using startup variables.
After the Thin Client is booted, a list of all IDs can be obtained with the following command:
To get information on type and restrictions, the following command can be used:
The IDs can be used to change their settings with the following command:
amixer cset numid=2 1
cset informs amixer that a variable is to be changed by using the ID. In the example above, numid=2 is the ID and 1 is the given value for the ID.
- UCS Thin Client Services (TCS) manual: http://www.univention.de/fileadmin/download/documentation_english/ucs-tcs-handbuch_en.pdf