ClearOne MAXAttach plus 1-conference phone-w/2x ClearOne Max conf phones

The industry's first fully expandable tabletop conference phones. MAX provides premium, full-duplex audio in small conference rooms as a single unit and in larger rooms by linking up to four phone units for unrivaled microphone and loudspeaker coverage.

You can have up to 4 phone pods per base. However, the base only supports 1 analog (or equivalent) phone line.