<p>Click on the <img class="icon" src="http://www.tri-line.com/common/img/documentation/tim_professional/add_button.png" /> button beneath the list of trunks (right-hand window), to display the
following window.  Enter the trunk number and a name for the new trunk in the respective text boxes and press
the OK button.  If you don't enter a name, TIM will provide
one in the form 'Extn x' where x is the number of the trunk.</p>

<img class="screenshot naked" src="http://www.tri-line.com/common/img/documentation/tim_professional/adding_trunk.png" alt="Adding a new Trunk" />