Topic Last Modified: 2012-08-13
You can use direct SIP connections to connect Lync Server to either of the following:
An IP-PBX (for details, see Direct SIP Deployment Options).
A PSTN gateway (for details, see PSTN Gateway Deployment Options).
To implement a direct SIP connection, you follow essentially the same deployment steps as you would to implement a SIP trunk. In both cases, you implement the connection by using the external interface of a Mediation Server. The only difference is that you connect SIP trunks to an external entity, such as an ITSP gateway, and you connect direct SIP connections to an internal entity within your local network, such as an IP-PBX or a public switched telephone network (PSTN) gateway.