- LANCOM connected to LAN and WAN (via DSL/ADSL), ISDN-TE interface(s) are connected to the ISDN P2P connection, ISDN-NT interface(s) are connected to an ISDN PBX.
- The Internet connection has been set up. All terminal devices can contact each other with the IP addresses used.
- A dialing plan with a unique internal telephone number for each piece of terminal equipment to be connected.