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) an d 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 a s well as the GDS series of Facility Access products, users can easily sculpt a state-of-the-art security a nd 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.