Conference phones from Polycom are made up of speakers & microphones, which relay sound the same way a speakerphone does. Their design is such so that many people under the same roof can without trouble speak & hear callers sans needing to group near the same telephone device.
Conference phones more of often than not are made up of an all-inclusive handy unit, which is kept at a common center point and is connected to a normal phone cord. Models can have extra microphones for better functioning.
Nearly all usual speakerphones work in “half-duplex” style that activates the microphone and silences the speaker. Its design is there to stop feedback from crushing a call. But it leads to a problem. This sternly upsets the conversation’s natural flow, as only a single person can converse at a time. In case one person from within a group speaks up; the remote member’s voice is shut down. Thus if many people talk in tandem often, chats could finish off sounding irregular.
A stark contrast is Polycom conference phone which work in complete duplex style, thereby permitting two people to converse together at the same time. The box uses a digital processor for signals, or echo stopper that through digital signals stops feedback by eradicating sound of the speaker from microphone pickup. Basically, the echo stopper “listens” such signals from the speaker and does away with such sound. Both the caller and attendee can converse sans those disturbances and breaks.
Conferencing devices set up is as easy as just “plug and play” in case of a normal analog jack being there. Do not take this as granted, yet, as a large number of firms have phone systems that are now digital, which happen not to be compatible with conferencing devices. In case there not being a line for analog, an adapter can do that job. The adapter most probably do the job but then too check whether the connection with a device’s sound quality by using it.
Options are aplenty; consider them as per your equipment use. If you shall be often turning it on & off and taking it to use in various room sizes then buy one that allows easy expansion adjustments. Some have remote controlling or also wireless microphones so that while teleconferencing movement is not compromised.