switchboard
noun [ C ] uk/ˈswɪtʃ.bɔːd/ us/ˈswɪtʃ.bɔːrd/
电话总机，电话交换台
a piece of equipment, used especially in the past, for directing all the phone calls made to and from a particular building or area
Tearful fans jammed the radio station's switchboard after the singer's death (= so many people called that all the phones were busy). 歌手去世之后，伤心哭泣的歌迷纷纷打电话到电台，使总机忙得不可开交。
Ask the switchboard operator for the extension number you require. 让总机把你转到你要找的分机号。