Launch the Lync Server Control panel.
Select Voice Routing
In the New menu, click Site dial plan.
Click OK.
Click OK.
In the Commit menu, click Commit all
In the New menu, click Site policy.
Click OK.
Under Associated PSTN Usages, click New.
Click New.
Next to the Associated gateways text box, click Add.
Click OK.
Click OK.
Click OK to save your PSTN Usage record
Click OK to save the voice policy.
In the Commit menu, select Commit all.
Click Commit.
In the New menu, select Site trunk.
Click OK.
Click OK to save your selections.
In the Commit manu, select Commit all
Click Commit to published the voice routing configuration.