Expandable time slot interchanger

A method for distributing data contained in time slots of a time division multiplexed system in which a plurality of time slot interchange (TSI) modules are utilized comprising the steps of:

• receiving by a first TSI module a plurality of data corresponding to a number of time slots in one TSI frame and storing the data received during the frame;
• transmitting by the first TSI module all of said stored data to a next TSI module which receives and stores the data;
• each TSI module sequentially receiving all of the data in a frame from a preceding TSI module, storing the data in the frame, and retransmitting the stored data to the next TSI module;
• said first TSI module initiating transmission of data associated with a next TSI frame only after the data associated with the last transmitted frame is received by a last TSI module.

A time slot interchanger comprising:

• time slot interchange (TSI) modules each including means for receiving all time slot data in one TSI time frame via an inbound data bus, means for storing said time slot data, means for transmitting said received time slot data via an outbound data bus, and means for transmitting selected ones of the stored time slot data as output data on communication channels coupled to each TSI module,
• transmission channel means for connecting said outbound data bus of each TSI module to said inbound data bus of a next TSI module;
• and
• means for sequentially transferring said received time slot data from each TSI module to the next TSI module via said transmission channel means;
• and
• means for synchronizing said TSI modules so that said selected ones of the stored time slot data are not transmitted from any TSI module until every TSI module has received said time slot data for the same TSI frame.

A time slot interchange (TSI) module comprising:

• means for receiving all time slot data in one TSI time frame via an inbound data bus;
• means for storing said time slot data;
• means for transmitting said stored time slot data via an outbound data bus;
• means for transmitting selected ones of the stored time slot data as output data on a communication channel coupled to said TSI module;
• said transmitting means transmitting the selected ones of the stored time slot data as output data upon a predetermined number of TSI clock time periods having occurred since said time slot data was received by said receiving means.

A method for distributing data contained in time slots of a time division multiplexed system in which a plurality of time slot interchange (TSI) modules are utilized comprising the steps of:

• receiving by a first TSI module a plurality of data corresponding to a number of time slots in one TSI frame and storing the data received during the frame;
• transmitting by the first TSI module the received data to a next TSI module which receives and stores the data;
• each TSI module sequentially receiving the data in a frame from a preceding TSI module, storing the data in the frame, and retransmitting the received data to the next TSI module;
• and
• synchronizing the transmission of selected ones of the stored time slot data via communication channels coupled to end destinations so that the transmission of said selected ones does not begin until the last TSI module has received the same frame of data stored by a first TSI module.