622
COMpact 5000/R - Firmware V6.6A - Installation, Operation and Configuration V05 03/2016
Settings
VoIP
Configuring Remote Extensions
6. Check whether the VoIP subscriber was successfully registered on the PBX (see
Monitoring > Status int. VoIP subscribers
).
7. If necessary, enable DiffServ, to increase VoIP call quality (Quality of Service (QoS)).
8. If necessary, make the VoIP settings (Jitter buffer, Echo cancellation) for the VoIP
subscribers to improve the call quality.
Configuring Remote Extensions
In order to operate a VoIP telephone as a remote extension, it must either be connected to the
network via a VPN tunnel or the telephone and the PBX must establish the connection via a
publicly accessible STUN server on the Internet and a DynDNS service as described in the
following.
Important:
As a protection measure against the access by third parties, regularly check
the call data recording of your PBX and the LOGs of your NAT router for
inconsistencies.
For security reasons, the connection of remote extensions by means of a
VPN tunnel should be preferred.
Note that when using a remote extension, emergency calls can only be
traced backed to the location of the PBX (localisation). Localisation is
necessary if the caller is no longer able to give his name and address.
Therefore, for emergency calls from a remote extension, a mobile telephone
or a telephone connected to the local VoIP or public switched network is
required.
Note:
In order to avoid that emergency calls are made from a remote extension, a
call restrictor should be configured for the various emergency numbers and
assigned to the subscriber. When the subscriber tries to dial an emergency
number, he will hear the announcement “This telephone does not allow
emergency calls. Please use an alternative.“
Caution:
Each port forwarding constitutes a security risk.
•
You should use as few forwarding configurations as possible.
