Who is making these calls?

Telekom is telemarketing other services (e.g. DSL) to their mobile phone customers.
Sometimes more of these computer-dialed calls are picked up than they have representatives. That's why sometimes you can get a call and no person is on the other side.

It's Telekom's sales force.  
They offered me DSL without activation fee if I switch away from my current internet provider.
I took some of his time until he gave up and tried to get out of the call.
So, I hope they marked me off and won't call back.
Some of you get no answer because more calls are automatically dialed than they have representatives. When too many cell phone owners actually pick up, some won't get a person on the line.

I just got a call from that number as well on my german cell phone.  I tried to call it back, but nothing happened.    Anyone figured it out?

I got exactly the same phone call. Did you figure anything out?

Same situation for me as for Bob.

Every weekday in the afternoon, I get a call from 800-300-9910 on my cell phone in Germany. There is no answer on the other end. I just let it ring now and it stops in a few seconds. However, this is very irritating.

I also got a call fron this number. No one spoke.