Simplify the following text for a Grade 10 native English-speaking person.
Original: He also insisted on having the radar operators linked via telephone ( whose wires were laid deep underground with concrete anti-bomb protection ) to an operational center : this was Fighter Command control at Bentley Priory .
Simplified: Radar operators were linked via telephone ( whose wires were laid deep underground with concrete anti-bomb protection ) p47 to an operational center . This center was Fighter Command control at Bentley Priory .