Yealink Model #s EHS 40 is compatible with : SIP VP59, T58A, T57W, T53W, T54W, T53, T48S, T46S, T42S, T41S PLEASE NOTE : If an expansion module has been connected to the SIP- T58A, T57W, T54W, T53W, or T43 IP phone, you can connect the EHS40 to the expansion module Leitner: Grab the adapter box, and the Jabra Y-cord (this y cord has the same exact ends on each side. 2 RJ45 and 2 RJ9 connections - one on each end) What is in the box : Yealink adapter box that has a USB cord coming out of it, 1 Sennhieser Y-cord, 1 Plantronics Y-cord, and 1 Jabra Y-cord. 1) Find the double Y-cord, the side where one click tab is facing up, and the one on the adjacent cord is facing down is going to be going into the headset base. The big one in the "AUX" jack and the smaller one next to it in the Headset jack. 2) Connect other end of the y-cord, with the click tabs on the same side, into the 2 available slots in the Yealink adapter box 3) Plug the USB cord coming out of the adapter box into the USB port…