What you’ll want to do is this--
Take the side of the y-cable with the rounded 3.5mm plug and the telephone cord.
• Plug the rounded 3.5mm plug into the accessory jack of the charging base that’s on the bottom right next to the power cable. The power cable is the larger port with the pin in it, the accessory port is the small black one.
• Plug the telephone cord side of that y-cable into port under the charging base with the picture of the whole telephone. This is the telephone jack closer to the back of the charging base.
• The front telephone port will remain empty. Your curly cord will stay plugged into the phone into the port that says HAC or has a picture of a handset.
Now take the other side of the y-shaped cable. This one will have two telephone cord ports, an RJ9 and an RJ11, one is slightly bigger than the other.
◘ Plug the smaller telephone cord into the HEADSET jack of the Avaya phone.
◘ Plug the slightly telephone cord into the jack right next door to the HEADSET jack. This will have some numbers and letters on it. (See Photo).
Now let’s have a look at the charging base.
♦ Make sure the compatibility is set to 3. This is set on the side of the base using your notched line as an indictor.
That’s it! You’re done! You can now answer calls at the touch of a button. LITERALLY!