I ordered this unit to find out that this works onlywith a single-line phone; meaning a typical home phone.It will NOT work in office environments, where you mayhave to plug the unit into your office phone - whichmay be connected to a private exchange or computer-basedmedia collaboration systems. Plantronics supportrecommended CT50 (wireless) or a simple S12 (wired)for their product lines for connecting to office phones.But all parties involved offered me excellent service -Amazon, HeadsetDiscounters, Plantronics. The phone itselfshould be good - Plantronics know their business. Hencethe 5 stars.