What product could we use to connect Plantronics or Sennheiser wireles

Despite what you may think, we do have such a connector cord!

Male 2.5mm to Male RJ45 Adapter Cord (CAT# 2180)

This handy-dandy cord can connect to Sennheiser or Plantronics wireless and then plug into a 2.5mm phone!

Note: When it comes to wireless headsets, we have to make sure the 2.5mm jack is in the phone base itself, not only in one of the handsets.