X0202 4 2008-04-25 0 0000877931 Vertical Communications, Inc. VRCC 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 2008-04-25 4 S 0 5000 0.1 D 7466062 I By Limited Partnerships Common Stock 2008-04-28 4 S 0 3000 0.1 D 7463062 I By Limited Partnships 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. (SSFQP), Special Situations Cayman Fund, L.P. (Cay), Special Situations Private Equity Fund, LP (PE), Special Situations Technology Fund, L.P. (Tech) & Special Situations Technology II, L.P. (Tech II), respectively. 3,939,804 shares of Common Stock are owned by SSFQP, 1,362,511 shares of Common Stock are owned by Cay, 1,330,184 shares of Common Stock are owned by PE, 127,814 shares of Common Stock are owned by Tech and 702,749 shares of Common Stock are owned by Tech II. The interest of Marxe & Greenhouse in the shares of Common Stock owned by SSFQP, Cay, PE, Tech, & Tech II is limited to the extent of his pecuniary interest. Austin W. Marxe 2008-04-29 David M. Greenhouse 2008-04-29