Profile: Voice & Data Networks, Inc. specializes in the design, implementation and management of telecommunication systems. Our products include phones, cards and accessories. We offer both corded and cordless headsets. The Avaya 6402 non-display voice terminal has single line digital terminal and fixed buttons for conference, transfer, hold, redial & speaker functions. The Avaya 2420 digital telephone has a large display screen with a 7-line x 29-character LCD. It is designed with 24 system call appearance/feature buttons.