System for switching multirate digitized voice and data
First Claim
1. A time division multiplex switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source channels having a predetermined byte rate, each of said input digital carrier lines carrying a predetermined plurality of full-rate channels, comprising:
- means for generating timing signals defining intervals for digital carrier timing;
means responsive to said timing signals for generating sequential address signals;
digital line controller (DLC) means responsive to said timing signals for assembling byte-organized input signals from said input digital carrier lines into DLC output signals and for distributing byte-organized DLC input signals to said output digital carrier lines;
means for determining an indication of the frame offset of signals for each of said source channels with respect to said timing signals;
processor means responsive to said frame offset indications for calculating signal memory addresses;
signal memory means having the capacity to store at least one byte of said byte-organized signals for each source channel for an interval of time defined by the byte rate of the source channel;
control memory means for storing at least one of said calculated signal memory addresses for each source channel in said input digital carrier lines and for generating signal memory addressing signals;
said signal memory means being responsive to said signal memory addressing signals and to said sequential address signals to store successive bytes of said DLC output signals and to generate successive bytes of said DLC input signals.
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Accused Products
Abstract
A system for efficiently switching time multiplexed digital signals of different bit rates. A switch is described including switch modules each of which can switch data and/or voice 56 kilobit/second (kb) full-rate channels and 2.4 kb, 4.8 kb, and 9.6 kb subrate channels. All signals from incoming channels are stored in a signal memory and are transmitted to outgoing channels under the control of addresses stored in a control memory. The frame offset of each channel with respect to a standard superframe is detected and used to calculate the addresses to be stored in the control memory. Various arrangements are shown to minimize high speed signal and control memory requirements, and to simplify the process of generating control memory contents.
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Citations
30 Claims
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1. A time division multiplex switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source channels having a predetermined byte rate, each of said input digital carrier lines carrying a predetermined plurality of full-rate channels, comprising:
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means for generating timing signals defining intervals for digital carrier timing; means responsive to said timing signals for generating sequential address signals; digital line controller (DLC) means responsive to said timing signals for assembling byte-organized input signals from said input digital carrier lines into DLC output signals and for distributing byte-organized DLC input signals to said output digital carrier lines; means for determining an indication of the frame offset of signals for each of said source channels with respect to said timing signals; processor means responsive to said frame offset indications for calculating signal memory addresses; signal memory means having the capacity to store at least one byte of said byte-organized signals for each source channel for an interval of time defined by the byte rate of the source channel; control memory means for storing at least one of said calculated signal memory addresses for each source channel in said input digital carrier lines and for generating signal memory addressing signals; said signal memory means being responsive to said signal memory addressing signals and to said sequential address signals to store successive bytes of said DLC output signals and to generate successive bytes of said DLC input signals. - View Dependent Claims (12, 13, 14, 15)
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2. A time division multiplex switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, in which each of said input and output digital carrier lines transmits a predetermined number of full-rate channels, each of said source channels having a predetermined byte rate, comprising:
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means for generating timing signals defining intervals for digital carrier timing and defining full-rate channel, frame and partial superframe intervals; means responsive to said timing signals for generating sequential address signals; digital line controller (DLC) means responsive to said timing signals for assembling byte-organized input signals from said input digital carrier lines into DLC output signals and for distributing byte-organized DLC input signals to said output digital carrier lines; signal memory means having the capacity to store at least one byte of said byte-organized signals for each source channel for an interval of time defined by the byte rate of the source channel; control memory means for storing at least one signal memory address for each source channel in said input digital carrier lines and for generating signal memory addressing signals; means responsive to said timing signals for achieving frame synchronism of signals on said input digital carrier lines; means for measuring the magnitudes of frame offset with respect to said timing signals defining intervals for partial superframes for full-rate channels on said input digital carrier lines and for generating frame offset signals representing said magnitudes; and processor means responsive to said frame offset signals to generate and store said signal memory addresses in said control memory means; said signal memory means being responsive to said signal memory addressing signals and to said sequential address signals to store successive bytes of said DLC output signals and to generate successive bytes of said DLC input signals. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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16. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals for accessing said channels, each of said input digital carrier lines carrying a predetermined plurality of full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, said first source and second destination subrate channels operating at a predetermined byte rate, comprising the steps of:
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determining the frame offset of signals of said first subrate channel; calculating an identity of said first subrate channel adjusted for said frame offset; storing said identity of said first subrate channel at a location associated with the identity of said second subrate channel; storing an input byte from said first subrate channel at a time designated for accessing said first subrate channel and at a location associated with said identity of said first subrate channel for an interval of time defined by said predetermined byte rate; reading said identity of said first subrate channel at a time designated for accessing said second subrate channel at said location associated with the identity of said second subrate channel; reading said input byte stored from said first subrate channel at said location defined by said identity of said first subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel. - View Dependent Claims (17, 18)
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19. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals for accessing said channels, each of said source and destination subrate channels being transmitted on full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, comprising the steps of:
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measuring the frame offset of said first subrate channel; storing an identity of said first subrate channel, said identity modified in accordance with said frame offset, at a location associated with the identity of said second subrate channel; storing an input byte from said first subrate channel at a time designated for accessing said first subrate channel and at a location associated with said identity of said first subrate channel for an interval of time equal to the interbyte interval of the predetermined byte rate of said first and second subrate channels; reading said identity of said first subrate channel at a time designated for accessing said second subrate channel at said location associated with the identity of said second subrate channel; reading said input byte stored from said first subrate channel at said location defined by said identity of said first subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel. - View Dependent Claims (20, 21)
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22. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals from accessing said channels, each of said source and destination subrate channels being transmitted on full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, comprising the steps of:
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measuring and storing the frame offset of each full-rate channel; storing an indication of the subrate of each full-rate channel; storing the identity of said first subrate channel at a location associated with the identity of said second subrate channel; accessing said stored indication of the subrate and the frame offset of the full-rate channel which transmits said first subrate channel; generating a storage address defined by the identity of said first subrate channel and said accessed stored indications; storing an input byte from said first subrate channel at said storage address at a time designated for accessing said first subrate channel for an interval of time equal to the interbyte interval of the predetermined rate of said first and second subrate channels; reading said identity of said first subrate channel at a time designated for accessing said second subrate channel at said location associated with the identity of said second subrate channel; reading said input byte stored from said first subrate channel at said location defined by said identity of said first subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel.
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23. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals for accessing said channels, each of said input digital carrier lines carrying a predetermined plurality of full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, said first source and second destination subrate channels operating at a predetermined byte rate, comprising the steps of:
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determining the frame offset of signals of said first subrate channel; calculating an identity of said first subrate channel adjusted for said frame offset; storing the identity of said second subrate channel at a location associated with said identity of said first subrate channel; reading said identity of said second subrate channel at the time designated for accessing said first subrate channel, at said location associated with the identity of said first subrate channel; storing an input byte from said first subrate channel at said time designated for accessing said first subrate channel and at a location defined by said identity of said second subrate channel for an interval of time defined by said predetermined byte rate; reading said input byte stored from said first subrate channel at said location defined by said identity of said second subrate channel at the time designated for accessing said second subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel. - View Dependent Claims (24, 25)
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26. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals for accessing said channels, each of said source and destination channels being transmitted on full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, comprising the steps of:
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measuring the frame offset of said second subrate channel; storing an identity of said second subrate channel, said identity modified in accordance with said frame offset, at a location associated with the identity of said first subrate channel; reading said identity of said second subrate channel at the time designated for accessing said first subrate channel, at said location associated with the identity of said first subrate channel; storing an input byte from said first subrate channel at said time designated for accessing said first subrate channel and at a location defined by said identity of said second channel for an interval of time equal to the interbyte interval of the predetermined byte rate of said first and second subrate channels; reading said input byte stored from said first subrate channel at said location defined by said identity of said second subrate channel at the time designated for accessing said second subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel. - View Dependent Claims (27, 28)
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29. In a time-division multiplexed switching system for switching multirate digitized byte-organized signals from source channels carried on input digital carrier lines to destination channels carried on output digital carrier lines, each of said source and destination channels having a predetermined byte rate and each having associated designated time intervals for accessing said channels, each of said source and destination channels being transmitted on full-rate channels, a method of switching the signals from a first one of said source subrate channels of said input digital carrier lines to a second one of said destination subrate channels of said output digital carrier lines, comprising the steps of:
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storing an indication of the subrate of each full-rate channel; measuring and storing an indication of frame offset of each full-rate channel; storing the identity of said second subrate channel at a location associated with the identity of said first subrate channel; reading said identity of said second subrate channel at the time designated for accessing said first subrate channel, at said location associated with the identity of said first subrate channel; storing an input byte from said first subrate channel at said time designated for accessing said first subrate channel and at a location defined by said identity of said second subrate channel for an interval of time equal to the interbyte interval of the predetermined byte rate of said first and second subrate channels; accessing said stored indication of the subrate and the frame offset of the full-rate channel which transmits said second subrate channel; generating a storage address defined by the identity of said second subrate channel and said accessed stored indications; reading an input byte from said first subrate channel at said storage address at a time designated for accessing said second subrate channel; and transmitting said input byte stored from said first subrate channel to said second subrate channel.
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30. A time division multiplex switching system for switching multirate digitized byte-organized signals from one source channel carried on one input digital carrier line to a plurality of destination channels carried on output digital carrier lines, said source channel having a predetermined byte rate, comprising:
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means for generating timing signals defining intervals for digital carrier timing; means responsive to said timing signals for generating sequential address signals; digital line controller (DLC) means responsive to said timing signals for assembling byte-organized input signals from said input digital carrier line into DLC output signals and for distributing byte-organized DLC input signals to said plurality of destination channels on said output digital carrier lines; signal memory means having the capacity to store at least one byte of said byte-organized signals for said source channel for an interval of time defined by the byte rate of the source channel; control memory means for storing at least one signal memory address for each of said plurality of destination channels in said output digital carrier lines and for generating signal memory addressing signals; said signal memory means being responsive to said signal memory addressing signals and to said sequential address signals to store successive bytes of said DLC output signals and to generate successive bytes of said DLC input signals.
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Specification