pascom Cloud Phone System Documentation and Release Notes

pascom Desktop App Installation

How to install the pascom desktop UC client on Windows, macOS and Linux.

Modify Your Firewall

Many companies do not have any Internet access restrictions and can therefore immediately start using the pascom desktop UCC client without needing to make any alterations to their Firewall.

However, should you choose to, you can specify which internet services your company network is permitted to access by opening the following ports and allowing the pascom desktop client access in order to ensure that your pascom phone system operates optimally:

Configure Firewall / Port Overview

Configuring your own proxy server in the pascom client

If you operate your own proxy server in your company, which controls the data traffic to the Internet, the pascom client must be configured accordingly.

How to set up your proxy server data in the pascom client is explained in this HowTo.

Windows Installation

The Windows installation process does not require any admin privileges and be performed directly in the home-directory of the currently logged in user:

Windows Silent Installation

A silent installation is an installation method for software where no user interaction is required and no graphical user interface is displayed. With a silent installation, all necessary installation parameters are set in advance and the installation runs in the background without the user having to confirm or select anything. You can customise the target of the installation package via the properties or start the installation package via the command line.

pascom-installer.exe /S

A shortcut for the pascom app is also automatically created on the desktop.

Setting the autostart behaviour

To simultaneously adjust the autostart behaviour of the pascom app during installation, you can use the following command line parameter.

Silent Uninstallation

Proceed in the same way as for the installation. You will find the uninstaller in the app directory of the pascom app.

uninst.exe /S

Windows QoS Settings (Optional)

In order to achieve the maximum voice quality, the pascom client marks all voice data accordingly with QoS flags.

With the exception of Windows, this happens automatically on all other platforms.

The following group policies “Policy-based QoS” are required under Windows to mark the packages accordingly.

The group policies are created under the following path:

Local Computer Policy > Computer Configuration 
> Windows Settings > Policy-based QoS
Policy 1 Policy 2 Policy 3
Policy Name pascomSIP pascomRTP pascomXMPP
 Application Name  pascom Client.exe   pascom Client.exe  pascom Client.exe
 Protocoll  TCP and UDP   UDP  TCP
 Source Port  *   *  *
 Destination Port    5060:5062   30000:35000  5222
 Source-IP    *    *  *
 Destination-IP  *   *  *
 DSCP Value  24   46   24
 Throttle Rate  -1   -1  -1

Terminalserver Installation

(Optional) On the Microsoft Terminal Server it is possible to install the pascom desktop client directly in the programmes directory instead of the corresponding user’s home directory.

The disadvantage of this type of installation is that you will need to manually perform all pascom desktop client updates, as the updates require admin rights. The advantage of terminal server installations is that you can save upto ca. 100MB storage space per user.

Before you start the installation, please uninstall 32-bit versions of the pascom client older than version 84.R2233, if available.

  • Download the Windows Desktop Client
  • Open the command prompt as an Administrator
  • Start the setup and specify the install directory


pascomClient-setup.exe /D=C:\Program Files\pascom Client

The automatic updates of the pascom client are only deactivated if the pascom client has no write permissions. This is the default behaviour if you use the example path. Otherwise, it may happen that auto-updates are activated and you have to deactivate them again via flags or environment variables.

Use RDP Split Mode on Terminal Server


Using the command line parameter --rdp or by setting the environment variable PC_RDP to 1 it is now possible to disable softphone and video support for the client on the Terminal Server. This allows the client on the Terminal Server to use the softphone of another client instance for telephony.

This allows e.g. to start one client instance within an RDP session and another one on the host computer. The instance running within the RDP session has the --rdp flag set, the outer one does not. Thus, a headset connected to the PC can be used for telephony.

What does this do?

  • Better audio quality, as the audio does not have to be transferred to the RDP session
  • Headset control (e.g. Accept via button on headset) works as a result.
  • Integrations in software running on a terminal server (e.g. Outlook, DATEV) still works.
  • Less CPU load on terminal servers, since audio and video are encoded and decoded via the client on the respective terminal device.
  • Call control is fully possible via each of the clients.

The feature works across platforms (Windows, macOS, Linux) and is not limited to RDP sessions.

Mac OS

  • Download macOS Desktop Client
  • Run the pascom Client.dmg file
  • Drag the pascom icon (red) on to the Applications folder
  • As soon as the copy process has been completed, you will be able to start the client

Installation on MAC with Apple M1 Silicon CPU

As soon as you want to install the pascom client on a MAC with Apple M1 Silicon chipset, the installer will ask you to install the Rosetta 2 program. This program ensures that you can use applications designed for a Mac with Intel processor.

Linux Installation

  • Download the Linux Desktop Client
  • Unpack pascom_Client.tar.bz2 in the home directoy
  • Create Ubuntu Application Icon with
  • Start the client via the Application Icon


tar jxvf ./Downloads/pascom_Client-7.17.10.R.tar.bz2

If you’re using an X-Window Session on Ubuntu 20.04 or 22.04, you need to additionally install the following libraries:

sudo apt install libxcb-cursor-dev

Windows Installer Command Line Parameters

Parameter Explanations
/S Enables an installation in to run in the background, without displaying any dialog windows.
/D=PATH Enables the defining of the installation folder, i.e path. This parameter must always be the last parameter in the command line and only supports absolute file paths

Desktop Client Environment Variables and Command Line Options

The pascom Desktop Client supports a range of command line options and reacts to a nummber of environment variables on all operating systems.

Using the --help parameter for more information on which options and envirnoment variables are supported by your version of the pascom desktop client.


  --userDir <userDir>                    Set user directory. Via Environment:
                                         Set PC_USERDIR to desired value
  -h, --help                             Displays help on commandline options.
  --help-all                             Displays help including Qt specific
  --exec                                 Execute a command instead of starting
                                         a client instance. Example: --exec
                                         dial,*104 (Calls your own Voicemailbox)
  --noUpdate                             Disable automatic update. Via
                                         Environment: Set PC_NO_UPDATE to any
  --forceTouchMode                       Show UI like touchscreen is enabled
  --debugMode                            Debug Mode. Via Environment: Set
                                         PC_DEBUGMODE to any value.
  --pcRendererMode <pcRendererMode>      Change the used rendering backend.
                                         Possible values are: auto, opengl,
                                         openglSoftware, software. On Windows
                                         there are additional modes: D3D11,
                                         D3D11Software. On Windows and Ubuntu
                                         there are additional modes: vulkan,
                                         vulkanSoftware. On MacOS there are
                                         additional modes: metal. Via
                                         Environment: Set PC_RENDERER_MODE to
                                         desired value.
  --rdp                                  Disable all video and/or audio
                                         functionality on this client instance.
                                         Via Environment: Set PC_RDP to any
  --proxyServer <proxyServer>            Use the given server as proxy. Via
                                         Environment: Set PC_PROXYSERVER
  --proxyPort <proxyPort>                Use the given port for connecting to
                                         the proxy. Via Environment: Set
                                         PC_PROXYPORT, default: 3128
  --proxyUser <proxyUser>                Use the given user to authenticate
                                         against the proxy. Via Environment: Set
  --proxyPassword <proxyPassword>        Use the given password to authenticate
                                         against the proxy. Via Environment: Set
  --user <user>                          Override login username for first
                                         login. Via Environment: Set PC_USER to
                                         desired value. This value will be
                                         ignored after the first successful
  --password <password>                  Override login password. Insecure,
                                         please use PC_PASS environment variable
  --server <server>                      Override login server for first login.
                                         Via Environment: Set PC_SERVER to
                                         desired value. This value will be
                                         ignored after the first successful
  --disableHeadsetSupport                Set to true to disable automatic
                                         headset detection and controls. Via
                                         Environment: Set
                                         PC_HEADSET_SUPPORT_DISABLED to any
  --logSennheiserMessages                Log all communication from and to
                                         Sennheiser HeadSetupApplication. Via
                                         Environment: Set
                                         PC_LOG_SENNHEISER_MESSAGES to any
  --logPolyMessages                      Log all communication from and to Poly
                                         / Plantronics Hub Application. Via
                                         Environment: Set PC_LOG_POLY_MESSAGES
                                         to any value.
  --iceServers                           STUN/TURN Servers to use, comma
                                         separated. Via Environment: Set
                                         PC_ICE_SERVERS to desired value.
  --disableVideo                         Completely disable video support. Via
                                         Environment: Set PC_DISABLE_VIDEO to
                                         any value
  --enableWinks                          Enable usage of legacy winks API.
                                         Required for some webcams but may lead
                                         to crashes. Via Environment: Set
                                         PC_ENABLE_WINKS to any value
  --disableQueueState                    Disable queue state UI on this client.
                                         Via Environment: Set
                                         PC_DISABLE_QUEUE_STATE to any value
  --minimized                            Do not open the main window on
                                         startup. Via Environment: Set
                                         PC_MINIMIZED to any value
  --useCustomNotificationsAsDefault      Do not use native notifications by
                                         default. Via Environment: Set
                                         to any value.
  --limitJournalDays <limitJournalDays>  Limit the amount of locally
                                         synchronized journal entries to the
                                         specified number of days. Via
                                         Environment: Set PC_LIMIT_JOURNAL_DAYS
                                         to the desired value.