world's first commercial telephone exchange
... that New Haven, Connecticut, was home to the world's first commercial telephone exchange?
... that <a href="./New_Haven,_Connecticut" id="mwATY" rel="mw:WikiLink" title="New Haven, Connecticut">New Haven, Connecticut</a>, was home to the <b id="mwATc"><a href="./First_Telephone_Exchange" id="mwATg" rel="mw:WikiLink" title="First Telephone Exchange">world's first commercial telephone exchange</a></b>?