Spracht MCP-2016 Aura SOHO Full-Duplex Analog Conference Phone with Expandable Capability Version 1.0 The SOHO Conference phone comes with everything you need to start conferencing immediately SOHO Speakerphone has "echo cancellation" and active noise reduction utilizing SoundClear DSP (Digital Signal Processing) 3 built-in microphones provide 360 coverage for a 20' x 20' room. Fully Expandable: Add Bluetooth or PBX, Digital compatability by adding optional modules via the Accessory bay. Speakerphone has 'Redial' and 'Flash' buttons. Volume up and down toggle switch.