US 4,383,315 A · Idle time slot seizure and transmission facilities for loop communication system

Abstract

A time division multiplex loop communication system for voice and data is disclosed with multiaccess time slot seizure and data transmission capability from all station nodes without changing the idle, nonreserved, status of the seized time slot. A method and station node apparatus sends bursty data packets from a node when a time slot is not busy serving a longer duration voice telephone call. The apparatus eliminates the need for inefficient time slot request, acknowledgement and reservation procedures which require several TDM frames to complete and which are typically longer in duration than the bursty data packet to be transmitted. All stations have access to all time slots for bursty data transmission under control of loop interface circuitry which statistically ensures the successful data transmission from all sending nodes. The interface circuitry includes input and output buffers, slot and bit identification circuitry, bit stream retard circuitry, output selector circuitry, bypass decision circuitry, and data and voice insertion control circuitry comprising a slot decision control circuit, a seizure timing circuit and an acknowledgment check circuit.

Claims30

Dependent claims

A method for controlling a seizure of an idle one of a plurality of time slots in a time division multiplex loop communication system to transmit a packet of data information bits over a loop transmission path thereof and in that idle time slot while it retains its idle status, each of said time slots comprising at least one busy-idle status bit and information bits, each said status bit being marked busy for the duration of a call served by the respective time slot and being marked idle during intercall periods, said method comprising

storing a packet of data information bits,
examining said status bit of each one of said slots to identify the idle or busy status thereof,
seizing an idle one of said time slots in response to said examining identifying said idle one of said time slots, and
transmitting over said loop transmission path in said idle one of said time slots an idle status bit and the stored said packet of data information bits.

1 more element

In a time division loop communication system having a plurality of station ports disposed along a loop transmission means with time division multiplexing including a plurality of successively recurring time frames each of which comprises a plurality of time slots, each one of said time slots transmitting at least one bit for indicating the reserved or free status of said one time slot and digitally encoded information bits, and

each one of said ports comprising
means responsive to a receipt of a time slot free indicating bit of said one of said time slots and to a slot request signal for controlling a seizure of said one of said time slots,
means storing station information bits, and
means activated by said controlling means for transmitting from said one port onto said loop transmission means said free indicating bit and said station information bits in a seized one of said time slots.

1 more element

In a time division multiplex system having a plurality of station nodes located along a unidirectional loop transmission path and a recurring frame of time slots each of which comprises at least one busy-idle status bit and information bits, each said status bit being marked busy for the duration of a call served by the respective time slot and being marked idle during intercall period,

each of said station nodes including
as output buffer means for storing a packet of data, and
means responsive to a receipt of an idle status bit for one of said time slots on said loop transmission path for seizing said one of said time slots to control an insertion of the stored data packet from said buffer means into said idle time slot for transmission over said loop transmission path with said idle status bit of said one of said time slots to a destination one of said station nodes during the idle status of said one of said time slots.

each of said station nodes comprising
input buffer means for sequentially receiving for storage time slot status and information bits from an incoming link of said loop transmission path,
means for retarding by at least one bit time the received time slot status and information bits on said incoming link,
means cooperating with said retarding means for identifying each time slot of said frame and said status bit thereof,
output buffer means for storing voice/data information bits,
another output buffer means for storing a packet of data information bits, and
means responsive to a channel reservation request signal for controlling an insertion of the voice/data information bits stored in said output buffer means with a marked busy bit into an identified one of said time slots, and
data insertion control means responsive to the time slot idle status bit stored in said input buffer means and to a slot seizure request signal for controlling an insertion of said packet of data information bits with said idle status bit into an idle identified one of said time slots.

5 more elements

Dependencies are inferred from the claim text.

Idle time slot seizure and transmission facilities for loop communication system

Life of this patent

Idle time slot seizure and transmission facilities for loop communication system

Life of this patent

Abstract

Claims30