The Complete Handbook of Conference Phones

Chapter 1: Understanding Conference Phones

A conference phone is a specialized speakerphone designed to pick up and reproduce audio clearly for a group of people in a room, rather than for a single user holding a handset. It is a category of telephony equipment that sits between a simple desk phone and a complex, installed audio-visual system. The fundamental challenge it solves is audio pickup and delivery across a physical space, not just across a wire. It must allow multiple participants to speak naturally from their seats, while suppressing room noise and preventing the near-universal nuisance of audio feedback, or echo.

The core of any conference phone is its microphone system. A single omnidirectional microphone is sufficient for a lone speaker, but it will indiscriminately capture room noise, the rumble of an HVAC system, and paper shuffling. Modern conference phones therefore use a microphone array: a set of two or more (often up to eleven) individual microphone elements arranged on the device's housing. The audio processor in the device applies beamforming algorithms to combine signals from this array. A simple analogy is the difference between a wide-angle camera lens and a telephoto lens; the array acts as a dynamic telephoto lens, focusing on the direction of the person speaking. When a different person speaks, the array re-aims its focus in milliseconds. This is why you can place a high-quality unit in the center of a table and hear people clearly even if they are seated a few feet away,