A switchboard system includes an input/output section (11), first and second switches (12a, 12b) each for acting an active side switch or a standby side switch, a signal processing section (13) for processing received cells, and a control section (14). The control section (14) switches active side ascending cell routes from the then active side switch (12a) to the then standby side switch (12b), transmits a plurality of specified cells through the active side switch (12a) to the signal processing section (13), and receives the specified cells through the active side switch (12a), and switches active side descending cell routes from the then active side switch (12a) to the then standby side switch (12b).