| 摘要 |
A multi-user Time Division Multiplex (TDM) system includes a plurality of stations connected by one or more unidirectional data buses. A "queue of request" (QR) counter is added to each station having destination slot release capability. The QR count indicates how many outstanding requests there are for idle time slots from "downstream" stations. The QR counter is incremented when a station becomes active (i.e., has a data transmit request). The QR counter is decremented when a busy time slot is released to an idle time slot condition, as long as outstanding requests exist from downstream stations. When the QR count is negative (indicating more idle slots than requests), a station erases a request signal received from a downstream station. When the QR count is positive (more requeststhan idle slots), a station writes an additional request signal to upstream stations. When the QR count is zero, request signals are not altered by a station. A separate QR counter and associated circuitry is utilized by each unidrectional bus of the TDM system.
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