GNU Radio Question

Hi, i’m doing a real voice transmission using USRP E110 over GNU Radio.
When I execute the flow graph bellow GNU Radio shows things I really
don´t have idea of what is. it shows things like “UaUaUaUa”, “OaOaOa”
or “SSsSoA” so, my question is what does it means? Overload? Bad sample
rate? Anybody can help me?

I´ve attached some print screens of what i’m saying,

Thanks and regards.