Digital conference bridge

Claim 2

A digital conference bridgE comprising: k input terminals and one output terminal for combining in a conference hookup k delta modulation voice communication equipments that are operable at the same sampling rate, clock means having first, second, and third terminals, and delivering at the first terminal periodic pulses m at the sampling rate of the voice communication equipments, and delivering at the second terminal during two successive m pulse periods k+1 pulses, one of said k+1 pulses being coincident with an m pulse, and delivering at the third terminal one reset pulse for every two m pulses coincident with an m pulse and said one of said k+1 pulses, k line buffer stores, each having an input terminal for connection to the output terminal of one conferee equipment and having one output terminal and a shift terminal connected to the first terminal of the clock means whereby the succession of bits stored in the line buffer store is shifted by 1 bit in response to each m pulse whereby each line buffer store is readied for one incoming bit in response to each m pulse, k input 2-bit registers each having one input terminal connected to the output terminal of a respective line buffer store and having two output terminals for delivering two bits at the same time and having a reset terminal connected to the third terminal of the clock and also having a read terminal, an output 2-bit register and compare-if-equal means having two input terminals and one output terminal and a read terminal and a reset terminal, the latter being connected to the third terminal of the clock means, and being operable following a reset pulse and subsequent 11 bits or 00 bits delivered to the input terminals to inhibit the input terminals of said lastrecited means until the next reset pulse, an output buffer store having one input terminal connected to the output terminal of the output 2-bit register and having one output terminal for connection to the receive terminals of the conferee equipments and a third terminal connected to the first terminal of the clock means for shifting the succession of bits stored therein by 1 bit in response to each m pulse, and an electronic switch connected to the second terminal of said clock means and indexing and delivering a READ pulse in response to each pulse from the clock means, said switch interconnecting the input terminals of the output two-bit register and the output terminals of one of the succession of input two-bit registers and delivering the READ pulses to the switch-coupled input and output registers whereby the input 2bit register empties its bits and the output 2-bit register, when not inhibited by the compare-if-equal, reads the bits emptied by the input 2-bit register.

Claim 3

A digital conference bridge for combining in a conference hookup up to k delta-modulation voice communication equipments, inclusive, that are operable at a sampling rate m, said digital conference bridge comprising: k input terminals for coupling to transmit lines of the conferee equipments, a line buffer store, for storing a predetermined plurality of bits, connected in series with each input terminal, each of said line buffer stores having a shift pulse input operable in response to each shift pulse to shift the succession of bits stored therein by 1 bit and thereby to accept 1 bit from the input terminal, an input 2-bit register connected in series with each line buffer store and having a reset pulse input and a read pulse input, each of said input registers being operable in response to a reset pulse to empty 2 bits from the respective line buffer store and to store those two bits, and also being operable to empty the 2 bits stored therein in response to a read pulse, one output 2-bit register having a read pulse input and a reset pulse input anD operable when coupled to one of the input 2-bit registers and in response to a read pulse to the coupled registers to store the 2-bits emptied by the input register to which it is coupled, and also being operable in response to a reset pulse to be emptied of the 2 bits stored therein, an output buffer store coupled to the output register for accepting bits emptied by the output register and having a shift pulse input and operable in response to each shift pulse to shift the bits stored therein by 1 bit, said output buffer store also having an output terminal for connecting to the receive line of all the conferee equipments coupled to the input terminals, an electronic switch operable to couple the output register to the input registers successively in response to indexing pulses, for delivering bits emptied by the input register coupled thereby to said output register, a compare-if-equal means coupled to said output register and having a reset pulse input and operable to inhibit acceptance of any bits by said output register following delivery of a pair of bits thereto of the same kind, until reset, clock means providing a train of shift pulses at the sampling rate m to the shift pulse inputs of all the buffer stores, and further delivering to the electronic switch k+1 indexing pulses and k+1 read pulses to the registers during two successive m periods, one of the k+1 pulses being coincident with an m pulse during an interval between couplings of input registers to the output register, and further delivering a reset pulse to the registers and the compare-if-equal means in coincidence with the indexing pulse that occurs between couplings of said input registers to the output register.

Claim 4

A digital conference bridge for combining in a conference hookup up to k delta-modulation voice communication equipments, inclusive, that are operable at a sampling rate m, said digital conference bridge comprising: k input terminals for coupling to transmit lines of the conferee equipments, a line buffer store, for storing a predetermined plurality of bits, connected in series with each input terminal, each of said line buffer stores having a shift pulse input operable in response to each shift pulse to shift the succession of bits stored therein by 1 bit and thereby to accept 1 bit from the input terminal, an input 2-bit register connected in series with each line buffer store and having a reset pulse input and a read pulse input, each of said input registers being operable in response to a reset pulse to empty 2 bits from the respective line buffer store and to store those two bits, and also being operable to empty the 2 bits stored therein in response to a read pulse, one output 2-bit register having a read pulse input and a reset pulse input anD operable when coupled to one of the input 2-bit registers and in response to a read pulse to the coupled registers to store the 2-bits emptied by the input register to which it is coupled, and also being operable in response to a reset pulse to be emptied of the 2 bits stored therein, an output buffer store coupled to the output register for accepting bits emptied by the output register and having a shift pulse input and operable in response to each shift pulse to shift the bits stored therein by 1 bit, said output buffer store also having an output terminal for connecting to the receive line of all the conferee equipments coupled to the input terminals, an electronic switch operable to couple the output register to the input registers successively in response to indexing pulses, for delivering bits emptied by the input register coupled thereby to said output register, a compare-if-equal means coupled to said output register and having a reset pulse input and operable to inhibit acceptance of any bits by said output register following delivery of a pair of bits thereto of the same kind, until reset, clock means providing a train of shift pulses at the sampling rate m to the shift pulse inputs of all the buffer stores, and further delivering to the electronic switch k+1 indexing pulses and k+1 read pulses to the registers during two successive m periods, one of the k+1 pulses being coincident with an m pulse during an interval between couplings of input registers to the output register, and further delivering a reset pulse to the registers and the compare-if-equal means in coincidence with the indexing pulse that occurs between couplings of said input registers to the output register.

Claim 5

A conference hookup comprising in combination, a plurality of digital voice communication equipments of the same type and that operate at the same modulation rate, clock means, circuit means having input terminals connected to the transmit lines of each of the equipments respectively and having one output terminal connected to the receive lines of all the equipments and being connected to and controlled by said clock means to transfer to the output terminal the input transmitted to no more than one of the input terminals during each of successive uniform time intervals, and for each of the successive uniform time intervals canceling every input not transferred to the output terminal.

Claim 6

A conference hookup comprising in combination, a plurality of digital voice communication equipments of the same type and that operate at the same modulation rate, clock means, circuit means having input terminals connected to the transmit lines of each of the equipments respectively and having one output terminal connected to the receive lines of all the equipments and being connected to and controlled by said clock means to transfer to the output terminal the input transmitted to no more than one of the input terminals during each of successive uniform time intervals, and for each of the successive uniform time intervals canceling every input not transferred to the output terminal.

Claim 7

A digital conference bridge for combining in a conference hookup a plurality of digital voice communication equipments of the same type and that operate at the same modulation rate comprising: clock means, circuit means having input terminals for connection to the transmit line of each of the equipments respectively and having one output terminal for connection to the receive lines of all the equipments and being connected to and controlled by said clock means to transfer to the output terminal the input transmitted to no more than one of the input terminals during each of successive uniform time intervals and for each of the successive uniform time intervals, canceling every input not transferred to the output terminal.

Claim 8

A digital conference bridge for combining in a conference hookup a plurality of digital voice communication equipments of the same type and that operate at the same modulation rate comprising: clock means, circuit means having input terminals for connection to the transmit line of each of the equipments respectively and having one output terminal for connection to the receive lines of all the equipments and being connected to and controlled by said clock means to transfer to the output terminal the input transmitted to no more than one of the input terminals during each of successive uniform time intervals and for each of the successive uniform time intervals, canceling every input not transferred to the output terminal.

Claim 9

A digital conference bridge as defined in claim 4 wherein said circuit means includes an input delay means controlled by said clock means coupled to each input terminal respectively, and a single delay means controlled by said clock means coupled to the output terminal, and means controlled by said clock means operable to transmit information from one only of the input delay means to the output delay means during each of the successive uniform time intervals.