I have a few Yealink T22p phones around the office and looking at replacing my own somewhat crappy SPA921 with one of these new Yealinks. I'm trying to figure out how to use my plantronics headset with it though. The SPA 921 has like a 3.5mm headphone jack on the side of it for the headset while the Yealink has an rj-11. The headset cable itself is made of two parts. Can I get a part that connects between the join in the cable and an rj11 on the new phone or do I need a new headset?