TDMA communication system having common local path medium and local time slot for intraoffice calls

Claim 2

A multiple access communication system having a central station and a terminal station, said terminal station serving a plurality of subscriber stations, said central station and said terminal station exchanging downstream and upstream time-division multiplexed (TDM) signals over first commcn path medium, comprising: first control means in said central station for determining first and second time slots in each of said upstream and downstream TDM signals in response to a call-processing signal, establishing a connection between said first and second time slots of each TDM signal and transmitting a control signal to said terminal station; time-division multiple access interface circuits associated respectively with said subscriber stations and normally coupled to said first common path medium for transmitting said upstream TDM signal and receiving said downstream TDM signal; second control means associated with said interface circuits for transmitting said call-processing signal to said first control means when a call is to be established between two of said interface circuits; second common path medium; switch means responsive to said control signal for switching said two interface circuits from said first common path medium to said second common path medium; and time slot control means for respectively coupling said two interface circuits to said first and second time slots of each TDM signal and responsive to said control signal for determining a third time slot and switching said two interface circuits from said first and second time slots to said third time slot.

Claim 3

A multiple access communication system as claimed in claim 1, further comprising timing recovery means connected to said first common path medium for recovering a timing signal from said downstream TDM signal and timing generator means for generating a timing signal, wherein said second common path medium comprises: a pair of first and second data lines connected to said interface circuits; and a pair of first and second sync lines connected respectively to said timing recovery means and said timing generator means, wherein said switch means includes means for coupling said interface circuits to said first sync line to said timing recovery means to allow said interface circuits to synchronize with the recovered timing signal and responsive to said control signal for switching said two interface circuits from said first sync line to said second sync line to allow said two interface circuits to synchronize with the generated timing signal.

Claim 4

A multiple access communication system having a central station connected to a telecommunication switching system and a terminal station connected over first common path medium to said central station, said terminal station serving a plurality of subscriber stations, comprising: time-division multiplexer demultiplexer means for multiplexing signals from said switching system into a downstream time-division multiplexed signal and transmitting it to said terminal station over said first common path medium and demultiplexing an upstream time-division multiplexed signal received over said first common path medium into signals for application to said switching system; first control means for determining first and second time slots in each of said upstream and downstream time-division multiplexed signals in response to a call-processing signal to permit a talking connection to be established over said first and second time slots through said telecommunication switching system and transmitting a control signal to said terminal station in response to the establishment of said talking connection; time-division multiple access interface circuits connected respectively to said subscriber stations for transmitting said upstream time-division multiplexed signal to said central station and receiving said downstream time-division multiplexed signal therefrom; second control means associated with said interface circuits for transmitting said call-processing signal to said central station when a call is to be established between two of said interface circuits; second common path medium; switch means for normally coupling said interface circuits to said first common path medium and switching said two interface circuits from said first common path medium to said second common path medium in response to said control signal; and time slot control means responsive to said control signal for selecting a third time slot and switching said two interface circuits from said first and second time slots to said third time slot.

Claim 5

A multiple access communication system having a central station connected to a telecommunication switching system and a terminal station connected over first common path medium to said central station, said terminal station serving a plurality of subscriber stations, comprising: time-division multiplexer demultiplexer means for multiplexing signals from said switching system into a downstream time-division multiplexed signal and transmitting it to said terminal station over said first common path medium and demultiplexing an upstream time-division multiplexed signal received over said first common path medium into signals for application to said switching system; first control means for determining first and second time slots in each of said upstream and downstream time-division multiplexed signals in response to a call-processing signal to permit a talking connection to be established over said first and second time slots through said telecommunication switching system and transmitting a control signal to said terminal station in response to the establishment of said talking connection; time-division multiple access interface circuits connected respectively to said subscriber stations for transmitting said upstream time-division multiplexed signal to said central station and receiving said downstream time-division multiplexed signal therefrom; second control means associated with said interface circuits for transmitting said call-processing signal to said central station when a call is to be established between two of said interface circuits; second common path medium; switch means for normally coupling said interface circuits to said first common path medium and switching said two interface circuits from said first common path medium to said second common path medium in response to said control signal; and time slot control means responsive to said control signal for selecting a third time slot and switching said two interface circuits from said first and second time slots to said third time slot.

Claim 6

A multiple access communication system as claimed in claim 1, further comprising timing recovery means connected to said first common path medium for recovering a timing signal from said downstream TDM signal and timing generator means for generating a timing signal, wherein said second common path medium comprises: a pair of first and second data lines connected to said interface circuits; and a pair of first and second sync lines connected respectively to said timing recovery means and said timing generator means, wherein said switch means includes means for coupling said interface circuits to said first sync line to said timing recovery means to allow said interface circuits to synchronize with the recovered timing signal and responsive to said control signal for switching said two interface circuits from said first sync line to said second sync line to allow said two interface circuits to synchronize with the generated timing signal.