User guide

IP Network Connections 159
PBX Networking
Networking two Forum 523/524 systems using Q.SIG-IP requires
2 licences – one licence per system. The number of possible voice
connections is not restricted by the licence.
Go to the Telephony: Trunks: Trunk group page in the Con-
figurator to set up a Q.SIG-IP connection. Create a new bundle
and select the Access type “System Access”. Select “Q.SIG-IP”
under Protocol. Configure the IP address of the other system, the
port numbers to be used, the number of possible voice connec-
tions. Select a VoIP profile for the codec selection. Please refer to
the relevant help topics in the Online Help for the Forum 523/524
as well.
Note: Q.SIG-IP cannot be operated using a connection with NAT.
For a Q.SIG-IP connection, a branch connection or another VPN
connection is required.
Connection via SIP tie line
The Forum 523/524 communications system supports connections
using a SIP tie line for TC system networking. A SIP tie line is a
SIP line which requires no login which can establish multiple call
connections simultaneously. No SIP provider is required for estab-
lishing the connection via SIP tie line.
The number of simultaneous calls possible depends on the net-
work or internet connection capacity and the compression proce-
dure being used. The channels of a media gateway card are used
for a SIP tie line (see MGW Interface Card starting on page 116).
The data of a SIP tie line connection is subjected to codec com-
pression (see under Fundamentals starting on page 107 in the
chapter Voice over IP (VoIP)). Call data is transmitted directly
from terminal to terminal via the RTP protocol with SIP tie line as
well. In certain cases, for example when an incoming external call
is switched via multiple TC systems, there may be one or multiple
RTP proxies involved.
One of the special features of a SIP tie line connection is using
transparent codec interconnecting, for example to make use of HQ
audio or video telephony with appropriate terminals (see Trans-
parent codec interconnection starting on page 113). In addition,
you can find out what features are supported by the other station