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One-for-n modem control apparatus

  • US 4,245,342 A
  • Filed: 01/10/1979
  • Issued: 01/13/1981
  • Est. Priority Date: 01/10/1979
  • Status: Expired due to Term
First Claim
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1. In combination, plural on-line modem modules each including heterodyning and signalling modem means and controlled multiplexing means for connecting a first port thereof with one of second and third ports, said second port being connected to said modem means, a redundant modem module having heterodyning and signalling modem means connected to said third ports of said multiplexers in said on-line modem modules, said heterdyning means in said redundant module being frequency adjustable in accordance with a frequency control signal, priority assignment control means connected to said modem means and said multiplexers of said on-line modem modules for normally controlling said multiplexers to connect said first and second ports and responsive to sensing a failure of said modem means for connecting said first and third ports of said multiplexer of a failed one of said modem means, said control means including priority assignment means for connecting said first and third ports of only one of said multiplexers in accordance with a predetermined modem hierarchy, and frequency implementing means responsive to said control means connecting said first and third ports of a failed modem means for supplying said frequency control signal to said heterodyne modem means in said redundant modem module to substantially duplicate the operational frequency of said failed modem means said priority assignment control means comprising plural cascaded logic circuit means, one of said logic circuit means being included in each of said modem modules.

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