The new and advanced Yealink Headset Adapter EHS35 provides a technical interface between your desk phones and a compatible Yealink wireless headset. The unit is easy to install, simply connect the EHS35 to the RJ9 (4P4C) headset. Its plug-and-play effectively allows you remotely control your Yealink T3X phone calls, including answering, rejecting, holding, muting, hanging up, switching between multiple calls, and adjusting the volume. When using the EHS35 with Yealink/Avaya/Poly/Snom/ Grandstream/Fanvil desktop phone, it can provide audio but without remote control feature. It is specially designed to ensure maximum productivity in business applications such as receptions and call centers and is ideal for the Corporate, Financial, Health, Government, Educational, Industrial, and SME/SoHo market sectors.