A multi-line switchboard is a telephone operating system with multiple lines, allowing new callers to access the system even if the main operator is busy on another call. The switchboard itself serves as a hub from which calls can be directed to the correct party.
These type of switchboards are often found in professional settings such as large offices with many employees who have personal extensions. Calls to the office go to a single number and then are routed through the switchboard to the appropriate employee. They are also used to facilitate emergency response. Callers who need help dial a single number, and a switchboard operator routes them to the appropriate emergency service.