Switchboard commonly refers to old telephone systems, less used in modern digital contexts. In old movies, you might see an operator connecting calls on a switchboard.
Pro Tip 2/3
Human Operator
Switchboard often implies that a person, the operator, is manually connecting calls. She worked as a switchboard operator, dealing with dozens of calls each hour.
Pro Tip 3/3
Not Automated
Don't confuse switchboard with automated systems; switchboards usually need human input. When you call customer service, you don't reach a switchboard but an automated menu.