 In 2009, Polycom introduced the CX300 USB phone, optimized for Microsoft Office Communications Server 2007 R2.In its second release (CX300 R2), this USB phone operates as a plug-and-play device with Skype for Business, Microsoft Lync 2013, and Microsoft Lync 2010.A user can communicate using the handset, plug in a headset (RJ9 plug in rear), or use it as a speakerphone when the handset is left on-hook.