Attention!
If you're going to hold, attend or call into, a meeting, then it's incumbent on you to observe one simple rule:
Pay attention.
Don't look at your phone. Don't check emails on your laptop. Don't read your notes and other papers.
Pay attention. Focus on the discussion at hand.
Otherwise, cancel the meeting. Don't send someone else in your place, because you'll have to pick up the details at some point anyway and that also takes time. Instead, make a judgement. Either it's important or it isn't.
Pay attention.
It's not only the polite and appropriate thing to do. It sends a message.
If you don't pay attention, others pick up on it. They see what you're signaling. What you value (or don't).
It also says something about you - that you're the kind of person who is OK with wasting someone else's time. When you easily couldn't. That it's OK for your team to do the same if the meeting is with a similar audience (junior team member, another department, a vendor, etc.).
I once went to a meeting with the department head at a very large (and I mean, large) corporation - a meeting requested by that individual and attended by that person's direct reports - where the person spent almost the entire time working off of her laptop. The meeting was, as you might expect, pointless. No end result. A waste of everyone's time. I left the meeting with a sense in the back of my head that this person wasn't going to last in this role, because her behavior didn't jive with what I knew of the company.
Sure enough, within six months, this individual was no longer at that corporation. Not, I know, because of my meeting. But because of the sum total of the signals that were telegraphed at my meeting. And, no doubt, many others like it.
So be thoughtful of your actions, your intent, your signals. If it isn't adding value, cancel the meeting. You'll be doing everyone a favor.
Otherwise, pay attention.