| 摘要 |
An improved time division multiplexed switch, particularly useful in a private branch telephone exchange. Any number of ports, limited only by the drive capability of the devices used, may be connected to the switch. Each port may transmit or receive on any combination of data line and time slot. Each combination of time slot and data line comprises a path, the number of paths being equal to the product of the number of data lines and time slots. Connection between a transmit port and receive port is implemented by writing a path select control word consisting of a time slot select control word and a data line control word to registers associated with the port. The register for the data line select on the receive side latches the data line select command into the select inputs of a multiplexer connecting the port receive line to the appropriate one of a plurality of data lines shared by the ports. The time slot select portion of the path select command is latched into a register from which a counter is repetitively loaded. All counters are synchronously loaded at the beginning of a system frame and the counters are clocked by a signal toggling at the time slot rate. When the counter reaches a terminal count, an output goes active indicating that the transmit or receive port's time slot has been reached, thus enabling an interface device which then connects a utilization device to the appropriate highway data line.
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