T26P + EHS36 + CS540

[commsys]

Might not be related, but give this a try.

i had an issue with the 3.5mm audio cable plugging into the cs540, it appears that the length of the metal part was not as long as another suppliers cord (different brand). i used an different audio cable and it picks up and hangs up fine.

I attached a picture for reference. The one on the right is the Yealink one. It didnt work with the cs540, the one on the left did work.

Try to hold in the cable on the back on the cs540 (push it in and try to answer a call). if that doesn't work, try again by pushing it in and pushing downwards slightly. If this does work, it means you need a longer (metal part) cable.

Let me know how you go and if successful raise it with Yealink.