COMtrexx® VM

Hardware independent soft PBX solution with up to 250 users and up to 250 parallel calls per system

Virtualisation: flexible integration into your existing IT environment

Modern and transparent system

Flexible and scalable through the floating user licence model

Licensable up to 250 users

Configuration and monitoring via COMtrexx Control Center

Your advantages in detail

With scalability increased to 250 users with up to 250 simultaneous calls, the COMtrexx Soft PBX solution enables access to new, purely software-centric marketplaces and expansion stages.
The optimised connection of the SIP terminals of the D series is the technical basis for the provision of important functions from the successful COMpact series.


Install COMtrexx now and benefit from:

  • up to a maximum of 250 users per system (and 5 devices per user)
  • up to 250 parallel calls
  • zero-touch provisioning of the latest generation, the commissioning of devices is carried out in an extremely time-saving, fully automated plug-and-play mode
  • optimised for operation with COMfortel D-series terminals
  • integrated conference solution with up to 10 parallel conference rooms and 20 internal participants each
  • roaming user function for setting up mobile workstations
  • convenience functions such as central caller lists as well as CTI and BLF possible with the COMfortel D series
  • seamless integration of Google contacts
  • integrated VPN server for secure connections to corporate networks
  • remote monitoring and backup via COMtrexx Control Center and Auerswald Remote Access

Mobile working is easily and securely supported by optional soft clients for computers, tablets and smartphones. The cost-effective COMfortel SoftPhone for voice and chat is available at the entry level. Those who need more extensive functions and more intensive integration into business processes will find the optimal UCC solution with PBX Call Assist.

Compatible products

Features & technical data

Everything you need to know about our products comes now. Scroll down for more information.

Comfort Features

  • Up to 250 users licensable
  • Up to 250 parallel calls possible1
  • Setting up groups
    • 128 call groups
    • up to 40 members per group
    • Fixed channels can be reserved for group calls
  • Automatic control centre (maximum 10 configurable)
  • Barred/approved numbers, 10 each for coming and going, total maximum 200
  • Call of any second destination in parallel to the registered primary device
  • Call data management with 18,000 data records
  • Call pick-up (e.g. from the integrated voicemail or from mobile app COMfortel SoftPhone)
  • Broker and mediate
  • Pickup
  • Protection against attacks by setting blocking lists (blocked IP addresses) and activating blocking times
  • Text before signalling (can be switched for groups and for the automatic switchboard)
  • Music on hold with switchable announcement text
  • Autoprovisioning for standard SIP phones2
  • Roaming user function
    • Enables individual users to log on and off at different telephones
    • Personal caller lists can be transferred to different workplaces
  • Centrally stored caller lists
    • User-specific caller lists are stored centrally in the system
    • Stored lists are available when a user logs on via the telephone
    • Access only possible via the user
  • Logging in and logging out a user via a telephone by PIN dial-in
  • Registration of max. 750 terminals possible

SIP convenience features for standard SIP phones

  • SIP-BLF, Busy Lamp Field acc. to RFC 4235
  • SIP-MWI (Message Waiting Indication), monitoring of the central voicemail and fax boxes acc. to RFC 3842
  • Pickup pre-check3

Communication platforms

  • Up to 10 conference rooms with 20 internal participants each (audio)
  • Up to 100 channels can be assigned simultaneously across all conference rooms

Central address books

  • 2,000 contacts
  • Separate address books for departments and multi-company operation
  • Import of VCF and CSV files
  • Address book provisioning via LDAP
  • Usage of Google Contacts

VoIP telephony

  • Call deflection
  • Call forwarding on busy (CFB), no reply (CFNR), unconditional (CFU) at carrier trunk, configuration dependent
  • Transfer of customer-specific calling number information with outgoing calls (CLIP no screening)
  • SIP compliant with RFC 3261
  • VoIP point-to-multipoint and point-to-point connection (SIP trunking)
  • MSNs in SIP-Trunk simultaneously
  • Integration of external extensions (information on the location of the telephone is taken into account in an emergency call) and mobile clients
  • VoIP-Codecs: G.711, G.722
  • High voice quality through optimised echo cancellation and wideband audio with G.722
  • Encryption of signalling/signalling (SIPS) and voice data (SRTP) for internal calls
  • Compatible to standard SIP telephones
  • Support of soft clients and COMfortel Softphone

Voicemail and fax

  • Message and fax forwarding via e-mail
  • Remote access of the voicemail boxes incl. voice guidance
  • Call acceptance and individual announcements depending on calling number, time and call type
  • Substitute function
  • Up to 250 fax mailboxes, each with 500 messages per box
  • Up to 250 voicemail boxes, each with 500 messages per box
  • Maximum 32 channels can be used for voicemail and fax

UCC functions

  • Call journal
  • Instant messaging for a better sharing of information
  • Platform independent (Windows, macOS, iOS, Android)
  • Presence management with automatic status detection
  • Alignment with MS Teams
  • Call setup and ending via the PC, incl. Outlook plug-in
  • Softphone-functions for Windows, Android und iOS
  • Up to 250 users can be licensed

COMfortel SoftPhone

  • Softclient for the base functionality SIP telefony and messaging
  • Secure and simple PBX connection from anywhere via Auerswald cloud service
  • Softphone for Windows, iOS and Android

Software interfaces

  • Access address books via LDAP
  • Support of basic CTI function via action URLs4

Installation and maintenance

  • Support of the COMtrexx Control Centre for secure remote control & backup management

Unlockable options

  • User licence: Activates all functions of the Soft PBX and is required for linking users to a device. One licence must be activated for each active/registered user on the system5
  • PBX Call Assist

Product variants

  • Available as .ova file for the vitualisation environment Oracle VM VirtualBox
  • Available as .ova file for the virtualisation environment VMware ESXi
  • Available as .vhdx file for the virtualisation environment Microsoft Hyper-V


  • For operation in a medium expansion stage of the COMtrexx VM, we recommend a virtual machine with the following performance data:
    • CPU: Intel Xeon E-2134
    • RAM: 16 GB DDR4 2666
    • SSD: 100 GB (system uses up to 20 GB)
  • Tryout mode can be activated
    • Can be activated for testing without initialisation and activation of licences
    • 3 free floating user licences included (can only be used in tryout mode). 
    • Time limited
  • The COMtrexx solutions can only be used in combination with floating user licences. You can obtain these and other licences from our authorised sales partners. Please note that additional services such as software maintenance and function extensions may cause additional costs.
1 Independent of the number of registered users in the system.
2 Supported for telephone models D-600/D-400/D-210/D-200/D-110/D-100 and WS-500S/M IP-DECT systems. Also partially supported are telephone models from other manufacturers such as Yealink and Snom
3 Is only supported for the telephone models D-400/D-600 and D-210/D-200 in operation with an extension.
4 Is supported for the telephone models D-600/D-400/D-210/D-200/D-110/D-100 from Auerswald
5 The licence can be used by several users ("floating"), provided that the total number of active users corresponds to the total number of licences in the system.
6 In tryout mode, provisioning for third-party terminals is not possible.

Trunk lines 1



VoIP channels (SIP acc. RFC 3261), point-to-multipoint/point-to-point connection (SIP trunking)

250 250

VoIP codecs

G.711, G.722 and G.729

User connection 1



VoIP subscribers

0 - 250 250

VoIP channels (SIP acc. RFC 3261)

0 - 250 250

VoIP codecs internal

G.711, G.722 and G.729

Voicemail and fax system



Voicemail channels

32 32

Fax channels

32 32

Voicemail boxes / fax boxes

250 250

Technical data



Supported operating systems

Windows 7/8/10, macOS, Linux

  • 1 Possibly depending on the configuration of the telephone system
  • 2 All VoIP channels are freely configurable between internal, external and dynamic

Delivery Scope


COMfortel® D-110

Entry level terminal with professional feature set that quickly proves its worth in demanding everyday use

COMfortel® WS-500M

One device, all scenarios: the WS-500M DECT multi-cell system ensures seamless mobile communication

COMfortel® WS-500S

The single-cell IP DECT system that can handle so much more when needed

COMfortel® M-730

The tough one: designed for challenging working environments

COMfortel® M-720

The elegant one: compact, well-designed, and powerful

COMfortel® M-710

The versatile one: full featured at an unbeatable price. The ideal entry.


COMfortel® D-600

High-level design – COMfortel D-600, the premium SIP device

COMfortel® D-400

Office or home office – the COMfortel D-400 SIP phone is the professional choice

COMfortel® D-210

Professional SIP-Phone  –  amazing range of premium functions despite almost entry-level price


PBX Call Assist 5

Unified communications solution with CTI, cross-media presence management and individual/group chat

COMfortel® SoftPhone

Softphone and messaging solution with mobile and secure connection to COMtrexx and COMpact ICT systems

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