telephone operator

radio telephone operator (RTO)

field telephone set

private line, telephone (PLT)

battery powered telephone

intratank telephone

telephone channel

telephone communication

telephone connection

wire telephone

amplifying telephone

voice telephone channel

electronic telephone switchboard

air traffic control operator

control tower operator

early warning system (EWS) operator

identification operator

operator control unit (OCU)

operator maintenance

operator’s pack

operator's permit

ship operator

aiming rule operator

azimuth (deflection) display board operator

control post operator

vertical control operator

fire-control operator

navigator-radio operator

air operator certificate

aircraft operator

airport operator

flight operator

flight radio operator