18 CLAIMS

• 1. A multiport switching element for providing and maintaining time and space switching for digitally encoded data received phase asynchronously in frames containing a plurality of channels of said data, said element coupling any of said channels at the input of the port receiving said channel to any channel at the output of any port in said element in response to digital command signals received by said port for said channel and in said channel, comprising:
• time division multiplexed common transmission bus means interconnecting said ports for providing a plurality of time slots, each time slot being dedicated to a particular channel of said frames coupled to the input of each port;
• means at each port responsive to said digital command signals for coupling said command signals and subsequent frames of data received in the channel in which said digital command signals are received to said common transmission bus means in the time slot dedicated to said channel; and
• means at each port selectively responsive to said digital command signals coupled to said common transmission bus means for extracting said frames of data from said common transmission bus means in the time slot dedicated to said input channel of said frames and for inserting said frames of data into the output channel designated by said digital command signals.
• 2. A multiport switching element in accordance with claim 1 wherein said means responsive to said command signals includes control logic means responsive to said command signals for selecting ports such that said switching element is operable as either a single-sided switching element or as a multisided switching element within a switching network.
• 3. A multiport switching element in accordance with claim 2 wherein said digital command signals comprise-in-channel multibit data words addressing a particular port.
• 4. A multiport switching element in accordance with claim 2 wherein said digital command signals comprise in-channel multibit data words for sequentially addressing the ports of said switching element until an available channel at any addressed port is located.
• 5. A multiport single-sided switching element in accordance with claim 2 wherein said control logic means includes means responsive to said digital command signals for initiating a connection from any port via said common transmission bus to any free channel of any port addressed by said command signals.
• 6. A multiport switching element in accordance with claim 2 wherein said control logic means further includes:
• means for coupling data either into or out of said port in response to said command signals, and in the same channel as said command signals including receive control logic for providing bit and word synchronization for said data; and
• transmit control logic for bit-synchronously transmitting said data from said common transmission bus means bit serially out of said port.
• 7. A multiport switching element for providing space and time switching between any ports thereof in response to digital command signals for frames of digitally encoded data in a plurality of channels received bit asynchronously by said switching element, comprising:
• time division multiplexed common transmission bus means interconnecting said ports;
• means at each port responsive to said command signals in said channels for coupling said data in said channels bit-synchronously from any of said ports to said common transmission bus; and
• means at each port selectively responsive to said command signals for extracting said data from said transmission bus in the bus cycle for said channel and for serially transmitting said extracted data bit-synchronously in the output channel designated by said digital command signals from said port.
• 8. A multiport switching element in accordance with claim 7 wherein said digitally encoded data comprises PCM encoded speech samples time multiplexed in said channels.
• 9. A multiport switching element for providing and maintaining time and space switching between any inlet port thereof and any outlet port thereof in response to in-channel digital command signals for frames of digitally encoded data in a plurality of channels bit asynchronously coupled to said switching element comprising:
• inlet port means for receiving and interpreting command signals in any of said channels, and for receiving data in any of said channels, subsequently to receiving said command signals in the same channel;
• time division multiplex common transmission bus means intercoupling said ports for providing a plurality of bus cycles, each dedicated to a particular channel;
• means for coupling said command signals from said inlet port bit-synchronously to said common transmission bus means and for coupling said data to said common transmission bus means in the same channels as said command signals; and
• outlet port means addressed by said digital command signals for coupling said data out of said port in any output channel designated by said command signals such that space switching is provided between said inlet port and said outlet port by said common transmission bus means and time switching is provided by the outlet port means.
• 10. A multiport switching element in accordance with claim 9 wherein said data coupled to said inlet port means and coupled from said outlet port means is rate synchronous.
• 11. A multiport switching element in accordance with claim 10 wherein said multiport switching element includes sixteen ports, each of said ports being intercoupled to each other by said time division multiplex common transmission bus means.
• 12. A multiport switching element in accordance with claim 11 wherein said time division multiplex common transmission bus means provides a 16-port space switch in a single frame time and wherein said outlet port provides a multiple channel time switch.
• 13. A multiport switching element in accordance with claim 10 wherein said digitally encoded data is PCM encoded speech samples time multiplexed in said channels.
• 14. A multiport switching element in accordance with claim 13 wherein said PCM encoded speech samples are n-bit linear data bytes.
• 15. A multiport switching element in accordance with claim 10 wherein said digitally encoded data comprises multibit companded PCM samples.
• 16. A multiport switching element in accordance with claim 10 wherein said digitally encoded data comprises multiplexed data bytes.
• 17. A method for establishing and maintaining time and space switching in a multiport switching element for digitally encoded data received phase asynchronously in frames containing a plurality of channels of data by coupling any of said channels received at the input of the port receiving said channel to any channel at the output of any port in said element in response to and designated by in-channel digital command signals received by said port for said channel and in said channel comprising the steps of:
• intercoupling said ports to a time division multiplexed common transmission bus such that a plurality of time slots each dedicated to a particular channel of said frames coupled to the input of each port are established;
• selectively coupling said frames of data at each port receiving said data in response to said digital command signals in the same channel as said data and preceding said data to said bus in the time slot dedicated to said channel such that said data is coupled phase synchronously to said bus;
• extracting said frames of data from said bus at each port selectively in response to said digital command signals and in the channels designated by said digital command signals; and
• phase synchronously coupling said extracted data from the output of said port and in the channels designated by said digital command signals.
• 18. A method in accordance with claim 17 further including the step of:
• selecting ports as inlets or outlets such that said switching element is operable as either a single-sided or a multisided switching element within a switching network.