Facsimile and static presentation processing – Facsimile – Facsimile system interface
Reexamination Certificate
1998-01-13
2001-07-10
Coles, Edward (Department: 2622)
Facsimile and static presentation processing
Facsimile
Facsimile system interface
C358S407000, C358S434000, C358S468000, C379S100150, C379S100170
Reexamination Certificate
active
06259538
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to facsimile transmissions and, more specifically, to a facsimile gateway for routing facsimile messages in real-time over packet-based networks.
BACKGROUND OF THE INVENTION
Traditionally, facsimile (“fax”) machines transmitted fax messages over the public switching telephone network (“PSTN”). The PSTN provides end-to-end connections between each fax machine. That is, for each call through the PSTN, there is a dedicated circuit set up between the two machines through which the date streams for the call are sent,
For many types of data traffic, Fe PSTN is a relatively inefficient transmission medium because it is circuit-based. To provide a connection whenever a caller desires one, the PSTN must be designed to handle the maximum amount of traffic that may flow through the network. Thus, at non-peak times, the network is underutilized. This is especially true for fax transmissions because most of the traffic flows from the originating fax to the destination fax, Typically, minimal traffic (e.g., a few signaling messages) flows in the other direction during the call.
Other networks have been developed to overcome the disadvantages of the PSTN. Some of the most prevalent alternative networks are packet-based networks. Packet-based networks such as the Internet provide more efficient data transmission by subdividing the data stream into blocks of data (referred to as data packets) and routing the data packets through the packet network. Significantly, the packet network does not provide a dedicated connection for each call, Rather, the packets associated with a given call may be routed at different times and through different nodes of the packet network. By breaking up the traffic in this manner, the switching and routing resources of the packet network are used more efficiently in comparison to comparable resources in the PSTN.
Although a packet network may be more efficient, the network may cause some of the traffic associated with a call to be delayed. This delay may cause problems in facsimile transmissions because conventional fax machines are designed to wait for a specific period of time for acknowledgments from the receiving fax machine, For example, an acknowledgment may be sent to indicate that the fax message was received in its entirety. If the originating fax machine does not receive an acknowledgment within the specified period of time, the originating fax machine may abort the transmission.
One proposed solution to this problem involves establishing two fax sessions. One fax session is established between the originating fax machine and its gateway to the packet network. Another fax session is established between the receiving fax machine and its gateway to the packet network, The gateways, in turn, communicate with one another over the packet network.
To compensate for delays in the packet network, the gateways provide acknowledgments and other handshaking signals to their associated fax machines, as necessary. For example, to prevent a time-out by an originating fax machine, its gateway may send an acknowledgment to the originating fax machine before the receiving fax machine successfully receives the complete fax message. It is left to the gateway to try to ensure that the fax message is successfully transmitted. To this end, the gateway typically stores the fax message and forwards it to the receiving fax machine at a later point in time. In the event that the fax message could not be successfully transmitted, recovery measures must be invoked to retransmit the fax message.
These recovery procedures may be cumbersome and inefficient. Thus, a need exists for a more transparent method of sending fax messages and receiving confirmations or error reports in real-time over packet-based networks.
SUMMARY OF THE INVENTION
The invention relates to a real-time gateway for a packet-based network fax transmission system. The gateway enables conventional fax machines to withstand transmission delays in the packet network. This is accomplished by intercepting the confirmation message that typically is generated by the conventional fax/modem in the gateway and by confirming that an entire fax message has been received only after the confirmation has been received from the receiving fax machine.
Typically, the gateway uses a fax/modem and adio board combination to interface with the originating fax machine. For example, a switch connects the line from the originating fax machine to either a fax/modem or an audio board. To enable the fax/modem to process inbound and outbound fax messages, the switch connects the line to the fax/modem. However, after an entire fax message (i.e., all of the pages in the fax) has been sent, the switch disconnects the fax/modem from the line and connects the audio board to the line, This prevents the fax/modem from sending a confirmation to the originating fax machine. The originating gateway (i.e., the gateway connected to the originating fax machine) then waits for the confirmation from the receiving fax machine via the packet network and the receiving gateway. If the confirmation is received, the audio board sends a confirmation message to the originating fax machine.
In one embodiment, the gateway is implemented using off-the-shelf PSTN interface boards, packet network interface boards, fax/modems and audio boards. The PSTN and packet network boards process fax calls to and from the PSTN, provide protocol conversion, as necessary, and provide packet network interface operations. The fax/modems provide the fax message processing and provide an interface to determine when the entire fax message has been sent The audio boards provide the message that emulates the confirmation message sent by the receiving fax machine.
Thus, a system for providing facsimile transmission over a packet-based network includes a standard fax/modem for providing facsimile protocol processing for the messages, an audio board for providing facsimile protocol messages to a facsimile machine, a switch or other mechanism for routing traffic associated with the facsimile machine to or from either the fax/modem or the audio board, and a controller for monitoring the facsimile messages and controlling the switch or other mechanism according to the monitoring operation.
REFERENCES:
patent: 4970603 (1990-11-01), Kanai
patent: 5432907 (1995-07-01), Picazo, Jr. et al.
patent: 5490247 (1996-02-01), Tung et al.
patent: 5805298 (1998-09-01), Ho et al.
patent: 5835240 (1998-11-01), Kobayashi et al.
patent: 5835579 (1998-11-01), Gersi et al.
patent: WO 97/10668 (1997-03-01), None
Dialogic Native NT Architecture -Beta 1 Reference.
MSI/SC Software Reference for Windows NT.
Amit Rami
Bachar Shmulik
Cohen Alon
Coles Edward
Darby & Darby
VocalTec Communications Ltd.
Wallerson Mark
LandOfFree
Real-time facsimile gateway does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Real-time facsimile gateway, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Real-time facsimile gateway will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2563953