無線 むせん呼出 よびだし符号 ふごうでしょう
musen'yobidashifugōdeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 無線呼出符号

1. Probably the call sign.; Possibly the radio call sign.

Polite
Presumptive
Conjecture