X0202 4 2006-01-20 1 0001000495 VISUAL NETWORKS INC VNWK 0001044321 MARXE AUSTIN W & GREENHOUSE DAVID M C/O SPECIAL SITUATIONS FUNDS 527 MADISON AVENUE, SUITE 2600 NEW YORK NY 10022 0 0 1 0 Common Stock 2006-01-20 4 J 0 3519202 1.8301 D 0 I By Limited Partnerships Warrants 4.2755 2006-01-20 4 J 0 157879 0 D 2002-03-25 2006-03-25 Common Stock 0 0 I By Limited Partnerships Convertible Bonds 1.45 2006-01-20 4 J 0 2000000 0 D 2002-03-25 2007-12-31 Common Stock 0 0 I By Limited Partnerships Convertible Bonds 1.45 2006-01-20 4 J 0 7661910 0 D 2005-08-09 2007-12-31 Common Stock 0 0 I By Limited Partnerships This is a joint filing by Austin W. Marxe (Marxe) & David M. Greenhouse (Greenhouse). They share voting & investment control over all securities owned by Special Situations Fund III QP, L.P. (QP), Special Situations Cayman Fund, L.P. (Cayman), Special Situations Private Equity Fund, LP (PE), Special Situations Technology Fund, L.P. (Tech) & Special Situations Technology II, L.P. (Tech II), respectively. 0 shrs of CS & 0 Convertible Bonds Cvt into 0 shrs of CS are held by QP, 0 shrs of CS & 0 Convertible Bonds Cvt into 0 shrs of CS are held by Cayman, 0 shrs of CS, 0 Wts & 0 Convertible Bonds Cvt into 0 shrs of CS are held by PE, 0 shares of CS, 0 Wts and 0 Convertible Bonds Cvt into 0 shrs of CS are held by Tech & 0 shrs of CS, 0 Wts & 0 Convertible Bonds Cvt into 0 shrs of CS are held by Tech II. The interest of Marxe and Greenhouse in the shares of Common Stock owned by QP, Cayman, PE, Tech, and Tech II is limited to the extent of his pecuniary interest. On January 20, 2006, all Common Stock (CS), Corporate Bonds and Warrants (Wts) owned by Special Situations Fund III QP, L.P, Special Situations Cayman Fund, L.P., Special Situations Private Equity Fund, L.P., Special Situations Technology Fund, L.P. and Special Situations Technology Fund II, L.P. were acquired. Austin W. Marxe 2006-02-15 David M. Greenhouse 2006-02-15