Angry callers flooded/jammed the company's 'switchboard'. [=made telephone calls to the company]
She used to work as a 'switchboard' operator.
(..) We were woken at am and told to get down here immediately. I don't know about that. - Call General McAddie. - I don't have the number. Call the switchboard. You don't know their number? - I'll call my CO. - We don't have time for you to dick around. Our order came from McAddie. Call him. (..)1998 The X Files