Digital tandem channel unit interface for telecommunications network
AssigneeAdtran, Inc.
InventorClifford L. Hall
Life of this patent
Estimating the term…
Abstract
A digital tandem channel unit installable in an intermediate central office of a digital carrier telephone network maintains the digital format of the T1 traffic in the course of a DS0 tandem cross-connect, so as to eliminates the possibility of corruption of voice/data traffic, as may occur in a conventional `analog` office cross-connect tandem pair due to quantization errors introduced into the data stream in the course of the digital to analog conversion of the data. Also, the invention incorporates control software in each tandem channel unit's micro-controller that allows it to respond to analog tone signalling test procedures initiated from either two or four-wire channel ports of network access equipment.
Claims19
For use with a telephone communication network containing a digital communication link over which digitized communication signals, including information signals and telephone equipment operation control signals that have been encoded into digital format, are conveyed between stations of said network, and wherein said network includes one or more intermediate stations coupled in said digital communication link, a respective intermediate station having first and second digital communication ports to which respective portions of said digital communication link are coupled, and an intra-station, cross-connect communication path through which incoming digital communication signals received at said first and second ports are interfaced to said second and first ports, respectively, and transmitted therefrom as outgoing digital communication signals, a method of effecting a digital cross-connect of received digital communication signals between said first and second ports comprising the steps of:
- (a) providing an intra-station digital communications path between said first and second ports of said intermediate station;
- (b) at one of said first and second ports, receiving incoming digital communication signals from said digital communications link, providing a pattern of digitally encoded synchronization signals and replacing selected incoming digital communication signals with signals of said pattern of digitally encoded synchronization signals to provide a digitally modified version of said incoming digital communication signals, and transmitting said digitally modified version of said incoming digital communication signals over said intra-station digital communications path to the other of said first and second ports;
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- (c) at the other of said first and second ports, receiving said digitally modified version of said incoming digital communication signals that has been transmitted over said intra-station digital communications path in step (b), and transmitting outgoing digital communication signals containing said information and equipment operation control signals as received at one port in dependence upon said pattern of digitally encoded synchronization signals contained in said digitally modified version of said incoming digital communication signals.
For use with a telephone communication network containing a digital communication link over which digitized communication signals, including information signals and telephone equipment operation control signals that have been encoded into digital format, are conveyed between stations of said network, and wherein said network includes one or more intermediate stations coupled in said digital communication link, a respective intermediate station having first and second digital communication ports to which respective portions of said digital communication link are coupled, and an intra-station, cross-connect communication path through which incoming digital communication signals received at said first and second ports are interfaced to said second and first ports, respectively, and transmitted therefrom as outgoing digital communication signals, a digital tandem channel unit which provides a digital cross-connect of received digital communication signals between said first and second ports comprising:
- an interstation-to-intra-station digital signal interface unit, which is coupled to one of said first and second ports and receives incoming digital communication signals from said digital communications link to which said one of said first and second ports is coupled, provides a pattern of digitally encoded synchronization signals, replaces selected incoming digital communication signals with signals of said pattern of digitally encoded synchronization signals to provide a digitally modified version of said incoming digital communication signals, and transmits the digitally modified version of the incoming digital communication signals over an intra-station digital communications path employed as said intra-station, cross-connect communication path;
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- an intra-station-to-interstation digital signal interface unit, which is coupled to said intra-station digital communications path, and receives a digitally modified version of digital communication signals that has been transmitted over said intra-station digital communications path from an interstation-to-intra-station digital signal interface unit to which the other of said ports is coupled, and transmits outgoing digital communication signals containing said information and telephone equipment operation control signals as received at said other port in dependence upon the pattern of digitally encoded synchronization signals contained in the digitally modified version of incoming digital communication signals received at the other port.
Dependencies are inferred from the claim text.