Dear Miyamoto-san.
Now we have a problem is to much with Adapter for NEC IP Phone is damage ( Power not coming ) is everyday
As you know we claim many time , and order to spare to support this case but not enough
Then have effect with
Then I need to help from you
Please check NEC to change model and part support our company
and also please order to replace as we have asap.
If you have any question please contact to me