I just got a Polycom IP560 phone and bought a Jabra Pro 920 headset with a 14201-17 EHS adapter, but can't get it to answer a call using the button on the headset. I went to Menu>Settings>Basic>Preferences>Headset>Hookswitch Mode and made sure it's set to Jabra EHS. Am I missing something? The headset itself works great if I push the button with the headset picture on it to answer.
It looks like you have the right cable and you have the Polycom phone on the correct setting, it should be working. I would recommend unplugging the AC power adapter and the EHS cord, then re-plug them both back in after 10 seconds. Also, try restarting your Polycom phone.
If neither of these steps work you could have a defective EHS cord. If that's the case and these were both ordered new, then you have a 1 year warranty from Jabra. Worst case scenario you might need to get a GN1000 with a Plantronics L bracket for remote answering.