The GSC3516 is a SIP/Multicast Talk-Back Speaker that allows offices, schools, hospitals, apartments and more to build powerful voice intercom solutions that expand security and communication. This robust SIP intercom device offers 2-way voice functionality with both a high-fidelity 15W HD speaker and 3 directional microphones with Multichannel Microphone Array Design (MMAD) and 1 omnidirectional auxiliary microphone that offer a 4.2 meter pickup distance. The GSC3516 supports a wide-range of peripherals including Bluetooth devices, built-in whitelists, blacklists and greylists to easily block unwanted calls, integrated dual-band Wi-Fi and advanced acoustic echo cancellation. By pairing the GSC3516 with other Grandstream devices, including desktop and cordless IP phones as well as the GDS series of Facility Access products, users can easily sculpt a state-of-the-art security and voice intercom solution. Thanks to it's modern industrial design, cleanable exterior surface and rich features, the GSC3516 is the ideal intercom speaker/microphone for any setting.