Fourth Extension Agreement

Exhibit 10.41

Fourth Extension Agreement

     This Fourth Extension Agreement is dated December 14, 2004 between Tollgrade Communications, Inc., having an address at 493 Nixon Road, Cheswick, PA 15024 (“Tollgrade”) and Dictaphone Corporation, acting through its Electronic Manufacturing Services Division, with an address at 3900 W. Sarno Rd., Melbourne, FL 32934 (“Dictaphone”).

      WHEREAS , Tollgrade (as successor in interest to Acterna Corporation) and Dictaphone are parties to a Supply Agreement dated July 25, 2002, which sets forth the terms pursuant to which Dictaphone manufactures and supplies to Tollgrade, and Tollgrade purchases from Dictaphone, certain products (the “Supply Agreement”);

      WHEREAS , the Supply Agreement was initially scheduled to expire on July 24, 2004, and has been successively extended through December 31, 2004;

      WHEREAS , Tollgrade and Dictaphone desire to replace the Supply Agreement with a new supply agreement, but have not y