In order to properly use a Jabra wireless headset with the following Aastra phones (6753i, 6755i, 6757i, 6757i CT). You will need two cables: the link below will take you to the kit that provides both the Jabra and Aatra cables required for remote answering and pick up of calls with the Jabra headset.
Without the kit you can still use the Jabra headset. The Jabra headset will work but you will need to manually answer and disconnect all calls by pressing the buttons on the Aastra phone. The jabra headset will not be able to pick up and answer calls without the required cables.