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

• Current Assignee: Intech Laboratories Incorporated
• Original Assignee: Intech Laboratories Incorporated
• Inventors: Entenman, Alan W.
• Primary Examiner(s): Atkinson, Charles E.
• Application Number:
  US06/002,332
• Time in Patent Office: 734 Days
• Field of Search: 340/146.1 BE, 340/147 SC, 235/303.3, 325/2, 325/40, 325/47, 325/56, 370/13, 370/16, 371/8
• US Class Current: 370/216
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

Communications apparatus includes one-for-n modem redundancy for a plurality of typically contiguously disposed modem modules. The modem modules comprise n active units each illustratively operating in a different frequency band and a redundant (spare) modem of electronically adjustable frequency. The on-line (active) modem modules each include a multiplexer which normally connects user terminal equipment associated with the module to the frequency translating and data and control signal processing circuitry in the module.

When a fault is detected in one of the modems (sensed, for example, by negated module "data valid" or "clear to send" levels for receive and transmit modems, respectively), a hierarchal control network and related apparatus automatically sets the redundant modem to the proper operating frequency and substitutes the spare for the failed unit via the appropriate multiplexer.

In an alternative, microprocessor controlled embodiment of the present invention, the dedicated priority of the hierarchal control network may be replaced by any desired algorithm for alloting the redundant modem among the n on-line unit.

Claims

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.

2. 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 heterodyning 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 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 microprocessor means connected to said modem modules for receiving signals representing the operative status of said plural module modem means, memory means connected to said microprocessor for storing a modem module hierarchy, and means connecting said microprocessor means and said module multiplexing means for selectively connecting said first and third ports of a failed one of said modem modules in accordance with the modem module hierarchy stored in said memory means.

3. A combination as in claim 2 wherein said frequency implementing means comprises storage means included in said redundant modem module, said microprocessor storing said frequency control signal in said storage means for controlling the operative frequency of said heterodying means of redundant modem module.