Aastra 400 Series System Manual page 353

Fig. 174 Conference circuit feature and three-party conference supplementary service
The figure below shows a three-party conference connected in the communication
server with one internal user and two exchange users:
Fig. 175 Three-party conference feature with 1 internal and 2 external users
The three-party conference feature is carried out locally in the communication
server. Two B channels are seized as a result.
If the system requirements are met, the three-party conference with one internal
and two external users can also be transferred to the exchange.
Fig. 176 Three-party conference as a service in the public network, with 1 internal and 2 external users
The supplementary service three-party conference is activated locally but moved
from the system to the public network. Only 1 B channel is seized as a result.
System functions and features as of R3.0
syd-0367/1.3 – R3.0 – 03.2013
Features
353