Common channel interoffice signaling system

Claim 1

In a telephone switching office having a switching network and a processor complex, a CCIS system comprising: first and second pluralities of terminal equipment for transferring CCIS data to said CCIS system from remotely located switching offices and from said CCIS system to said remotely located switching offices; first and second CPUs including an active and a ready standby CPU, each said CPU being connected to said processor complex; first and second CPU buses connected respectively to said first and second CPUs; first and second bus crossovers, each bus crossover connected to said first and to said second CPUs via said respective CPU buses and said crossovers operated to connect said first CPU to said second CPU bus and said second CPU to said first CPU bus; first and second bus extenders, each bus extender connected to said first and to said second bus crossovers, said bus extenders operated to connect said first and said second plurality of terminal equipment to said active CPU; first and second multiplexer means connected to said first and second bus extenders, said first multiplexer means operated to connect said first plurality of terminal equipment to said active CPU, said second multiplexer means operated to connect said second plurality of terminal equipment to said active CPU; first and second pluralities of buffer interface means corresponding to said first and second pluralities of terminal equipment, said first plurality of buffer interface means connected to said first multiplexer means, said second plurality of buffer interface means connected to said second multiplexer means, each buffer interface means operated to store and to forward said CCIS data between said active CPU and said terminal equipment; first and second pluralities of control circuits corresponding to said first and second pluralities of terminal equipment and buffer interface means, each control circuit connected between one particular buffer interface means and one particular terminal equipment and each control circuit operated to control said CCIS data transfer between said one particular buffer interface means and said one particular terminal equipment; each said buffer interface means is cyclically operated to transmit said CCIS data, received from said connected control circuit, to said active CPU via said corresponding CPU bus; and each said buffer interface means is cyclically operated to transmit said CCIS data, received from said active CPU, to said one particular terminal equipment via said connected control circuit.