Catalog # 2409 in website, the Leitner Electronic Hookswitch for Avaya 1400, 1600, and 9000 Phones. Here’s how you set it up: 1)Unplug the power cable from the back of the charging base 2) RHL/DHSG switch on the bottom of the Leitner wireless headset charging base to RHL. The sliding switch on the right should be set to 1. 2) Connect the y-side of the EHS that has the RJ45 and RJ9 telephone jacks to the Leitner wireless headset charging base in both the AUX jack (which is the largest jack in the center of the base) and the TELEPHONE CONNECTOR jack (the RJ9 jack 2nd from the right). 4) Connect the other side of the EHS cable into the HEADSET JACK of the Avaya or Shoretel Phone. 5) Last, plug your power cable back in to the back of the charging base. The ONLY models of telephone that work with this EHS are as follows. If your phone is not listed here, check out this article for instructions for another Avaya hookswitch!. Avaya 1408 1416 1608 1616 9504 9508 9611G 9621G 9641G J139 (remote…