Packet-switched facsimile network and method of operation

A data communication network including a plurality of source and destination data communication devices and a plurality of source and destination node systems, the network comprising in combination:

• a. a local telephone switching network PTSN for connection to the plurality of source and destination data communication devices;
• b. at least one packet switching network for connection to the source and destination node systems, in order to allow the plurality of source and destination data communication devices to communicate according to the following steps:
• (i). the plurality of source data communication systems transmitting at least part of the image data to a first source node system of the plurality of source node systems;
• (ii) said first source node system processing said part of the image data, and generating data packets therefrom;
• (iii) said first source node system with said processing step, transmitting said generated data packets to the destination node systems with minimal delay;
• (iv) the destination node systems receiving said data packets, and recovering said at least part of the image data from said data packets and selectively inserting fill codes between said converted converted at least part of the image data;
• and
• (iv) the destination node systems transmitting said converted at least part of the image data and fill codes to the data communication devices with minimal delay;
• such that said step of selectively inserting fill codes prevents service interruption between the plurality of source data communication devices and the plurality of destination data communication devices by correcting a temporary inability to receive additional data, and by maintaining real time communication between the plurality of source data communication devices and destination data communication devices.

A node system for use in a facsimile network including a plurality of source and destination data communication devices the node system comprising in combination:

• a. means for receiving image data from the plurality of source data communication devices;
• b. means for generating corresponding data packets from said received image data;
• c. means for sending said generated data packets to another node system with minimal delay;
• d. means for receiving data packets from another node system;
• e. means for forming image data from said received data packets;
• f. means for selectively inserting fill codes into said image data so that such selective insertion of said fill codes prevents service interruption between the plurality of source data communication devices and the plurality of destination data communication devices by correcting a temporary inability to receive additional data, and by maintaining real time communication between the plurality of source data communication devices and destination data communication devices;
• and
• g. means for sending said image data and said fill codes to the plurality of destination data communication devices.

A method of transmitting image data in a facsimile network including a plurality of source facsimile stations, a plurality of destination facsimile stations, a plurality of node systems for connecting the source and the destination facsimile stations, a plurality of local public telephone switching networks (PTSN's) for connecting to the source and destination facsimile stations over at least one transmission channel that connects the node systems, the method comprising the steps of:

• a. one or more of said plurality of source facsimile stations transmitting the image data to a source node system of the plurality of node systems;
• b. said source node system processing said part of the image data, and generating data packets therefrom;
• c. said source node system transmitting said generated data packets to a plurality of successive node systems along a plurality of different routes intermediate said source and destination node systems, with minimal delay;
• d. said destination node system receiving said data packets, and reconstructing the image data from said data packets and selectively inserting fill codes to prevent service interruption between the plurality of source and destination facsimile machines by correcting a temporary inability to receive additional data, and by maintaining real time communication between the plurality of source and destination facsimile machines;
• and
• e. said destination node system transmitting said reconstructed image data to one or more of said plurality of destination facsimile stations.