Thank you for asking this question in the support community forum. The NV3120 is VoIP/QoS ready and capable, but it will need to be configured. Here is a post that explains how to setup the unit depending if there are VoIP phones or a PBX behind the ADTRAN: NetVanta Series and Telephony (IP PBX or SIP Phones). Also, here is the Configuring QoS in AOS guide, which explains how to use the QoS wizard. However, if you have additional questions or information, please do not hesitate to reply to this post. I will be happy to help in any way I can.