I installed a DS16B on a IPO running 9.1.11. I tested the unit with a T7316e. The issue is only some of the buttons are being mapped to the phone. I have the first 16 (LCD) buttons set up as the usual CA, park, DSS etc. Buttons 17-24 (non LCD) work on the deskset as assigned. But none of the first 16 buttons are correct. They seem to have some kind of default buttons which I have not defined. The USER section shows the buttons assigned to that extension and user but they do not appear on the phone.