noun
also tran·spon·dor tranzˈpändə(r), traan-, -n(t)ˈsp-
( -s )
Etymology: transponder, from trans mitter + res ponder; transpondor, alteration (influenced by responsor ) of transponder
: a radio or radar set that upon receiving a designated signal usually in the form of a coded series of pulses emits a radio signal of its own that may also be coded — compare interrogator