Bleeper (5)
I believe the answer is:
pager
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bleeper</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pager that I've seen before include "Small radio bleeper for contact" , "Old electronic bleeping device" , "Way to contact" , "communicator?" , "Bleeper device" .)