An apparatus and methods supporting improved echo cancellation in a packet network is disclosed. The device includes a flexible member having first and second ends, a linear member fixed to the first end and slidingly coupled to the second end, a cam coupled to one end of the linear member and contacting a surface of the second end, and a lever arm coupled to the cam. The feed mechanism includes a drive motor coupled to a series of pulleys and belts that form an open-ended chain.