(Voice Over IP modem) A device that converts Internet-based voice service from the cable company to the user's telephones. A VoIP modem combines a DOCSIS cable modem and analog telephone adapter in one unit. Officially called an "embedded-multimedia terminal adapter" (E-MTA), the modem converts the cable company signals to packets and vice versa, and the terminal adapter converts the packets to analog voice and vice versa. The adapter also delivers dial tone and manages the call setup. CableLabs Certification PacketCable certification from CableLabs ensures that quality of service (QoS) and other critical telephony and real-time functions are supported for delivering multimedia over IP. See analog telephone adapter, VoIP, cable modem and DOCSIS.