Due to the increased volume of telephone traffic, the transfer points of VoIP providers may reach their capacity limits. A solution is sought by the providers through load balancing. The load distribution is done with a DNS SRV query. The DNS SRV is used to enable the provider to notify the registrars prioritised by him. The DNS resolution must be carried out by the provider. For this purpose, the router must use the DNS servers of the provider.

Early generations of hybrid telephone systems:

• COMpact 3000 analog, ISDN und VoIP
• COMpact 5010/5020 VoIP
• COMpact 5000 (R)
• COMmander Basic.2 / Basic.2 19“
• COMmander Business / Business 19“
• COMmander 6000 (R) (RX)

These systems do not support the dynamic procedure and can therefore no longer be operated on the respective VoIP account after platform changeover. In these cases, the ICT system must be replaced by a compatible system.

Current ICT systems:

• COMpact 4000
• COMpact 5200 (R)
• COMpact 5500R
• COMtrexx alle Varianten

Note the following points in the configuration:

• Configure the corresponding provider under Public networks, VoIP, Provider. The default value 5060 must be set as the registrar port and for the outbound proxy. The current templates are already preset for this.
• Under Administration, IP configuration, the IP of the router or gateway must be entered in the 1st DNS server field.

The COMfortel SoftPhone can only be used if the internal registrar is set to LAN1.

The required settings are described in the respective help for the telecommunications systems.

• Help COMtrexx
• Help COMmander 6000/R/RX
• Help COMpact 4000
• Help COMpact 5000/R
• Help COMpact 5200/5200R/5500R

Requirements

• Each user must have a valid PBX Call Assist 5 license with active software maintenance.
• The UCServer must be on the latest release (version 8.8.3 or higher).
• The UCServer's operating system is MS Windows Server 2016 or higher. The .NET Framework 4.8 is installed.
• The UCServer must be accessible from the internet:

via UCConnect / Mobility Services (a paid additional service from Estos)

- or -

configured according to the Estos best practice article https://support.estos.de/en/procall-enterprise/best-practice-ucserver-fuer-procall-mobile-apps-einrichten

Compatible web browsers

Chromium-based browsers, for example:

• Google Chrome™
• Microsoft^® Edge
• Mozilla Firefox^®
• Apple Safari

The following are not supported:

• Microsoft^® Internet Explorer
• Google Chrome or Mozilla Firefox on mobile devices such as iOS
• Old versions of Microsoft^® Edge (without Chromium)

PBX Call Assist Web does not support use on mobile devices such as smartphones or tablets running Android or iOS.
The respective PBX Call Assist Mobile App (for Android or iOS) should be used.

Note: The PBX Call Assist Client for Windows should be closed before using PBX Call Assist Web, if necessary.

Port Forwarding

The PBX Call Assist Web WebRTC application runs as a website (https://auerswald.procall.de) within a web browser and is delivered via the https protocol. This requires the https port (443, outbound) to be forwarded.
In summary, the most common port forwarding requirements for WebRTC are:

• Ports 80 and 443 for signaling
• Port 3478 (UDP and possibly TCP) for STUN
• Port 5349 (TCP) for STUN over TLS
• Ports for TURN relays, if required