Switchboard having a dual switching system

A switchboard system comprising:

• an input/output section for receiving/transmitting cells, said input/output section having a plurality of (m) external input terminals connected to m external input lines, m external output terminals connected to m external output lines, m internal input terminals and m internal output terminals;
• first and second switches each for acting an active side switch or a standby side switch, each of said first and second switches having m first ascending terminals, a plurality of (n) first descending terminals, n second ascending terminals, and m second descending terminals, said m first ascending terminals being connected to said m internal output terminals through m first ascending lines, said m second descending terminals being connected to said m internal input terminals, said in first ascending terminals being coupled to n first descending terminals by switching, said n second ascending terminals being coupled to said in second descending terminals by switching;
• a signal processing section for processing received cells, said signal processing section having n signal input terminals connected to said n first descending terminals of each of said first and second switches through n second descending lines, and n signal output terminals connected to said n second ascending terminals of each of said first and second switches through n second ascending lines;
• and
• a control section for controlling switching between said first switch and said second switch said control section consecutively controls during said switching so that said control section switches active side ascending cell routes from said first and second ascending lines of a then active side switch to said first and second ascending lines of the then standby side switch, that said input/output section transmits a plurality of specified cells through at least said first ascending lines and said second descending lines of said active side switch to said signal processing section, and receives said specified cells through at least said second ascending lines and said first descending lines of said active side switch, and that said control section switches active side descending cell routes from said first and second descending lines of said then active side switch to said first and second descending lines of said then standby side switch, each of given m and n being an integer.