So glad you asked! It’s easy!
When you’re not on a phone call and there’s no call coming in, corded Sennheiser headsets (like the Deskmate or Versmate) + the Sennheiser 3.5mm QD cord with call control (cat# 2290) can control music!
A click of the call control button will pause and start the song you’re listening to. A double-click will skip ahead to the next song. Neat, right?
The same is also true of the call control button on the corded Sennheiser earbuds. Imagine that!