Point of presence (POP) for digital facsimile network with spoofing capability to maintain fax session

• US 5,828,468 A
• Filed: 05/17/1996
• Issued: 10/27/1998
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: Dialogic Networks (Israel) Ltd. (Dialogic, Inc. (United Arab Emirates))
• Original Assignee: NKO, Inc. (MegaHertz Communications Corp)
• Inventors: Platteter, Dale T., Lee, Warren S., Copp, David W., Carrier, Neil P.
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): Williams, Kimberly A.
• Application Number:
  US08/649,239
• Time in Patent Office: 893 Days
• Field of Search: 358/400, 358/406, 358/407, 358/434, 358/435, 358/436, 358/438, 358/439, 358/440, 370/264, 370/346, 370/395, 370/399, 370/449, 370/524, 379/93, 379/94, 379/100
• US Class Current: 358/434
• CPC Class Codes: H04N 1/327 Initiating, continuing or ending a single-mode communication; Handshaking therefor H04N1/32614 takes precedence
• CPC Class Codes: H04N 1/32795 Arrangements for keeping the communication line open

Abstract

A fax network for communicating fax transmissions over either a conventional public switched telephone network or a digital (frame relay) network based on a telephone number of a destination fax machine. If the destination fax machine can be serviced by the digital network, a faxjack intercepts the phone digits on the telephone link, and redirects the call to a local point-of-presence, which is preferably located near the local exchange carrier. The POP receives information related to the desired fax transmission from the faxjack, and accesses a destination POP via the digital network. The destination POP is local with respect to the destination fax machine, and the destination POP attempts to contact the destination fax machine to ascertain if a fax session is allowable. If so, the destination POP notifies the source POP, which then notifies the faxjack, thereby allowing the fax session to start. The source POP packetizes the analog fax data received from the sending fax machine, and sends the fax data as packets over the digital network to the destination POP. The destination POP unpacketizes the data, and sends the fax data using a standard protocol and a standard local telephone link to the destination fax machine. Each of the POPs also has the capability to spoof the faxjack in order to maintain the fax session.

Claims

1. A method of providing a spoofing operation in a facsimile session over a digital data link, comprising the steps of:

receiving, at a first point of presence, a request to send a fax transmission over the digital data link, said request indicating a source fax machine that is making the request and indicating a destination fax machine that is to receive the fax transmission;

determining, at the first point of presence, a maximum allowable reception time for receiving an acknowledgement of the request made by the source fax machine;

relaying the request over the digital data link in a packetized format to a destination point of presence;

monitoring, at the first point of presence, an elapsed time from when the request was received to determine if the maximum allowable reception time will be exceeded within a first amount of time;

if the first amount of time is reached, sending a signal corresponding to the acknowledgement of the request to the source fax machine irrespective of whether the destination fax machine is actually able to receive the fax transmission;

determining, by the second point of presence, if the destination fax machine is able to accept the fax transmission;

if the destination fax machine is determined to be able to accept the fax transmission, receiving an acknowledgment signal sent by the destination fax machine at the second point of presence and relaying the acknowledgement signal sent by the destination fax machine to the first point of presence in the packetized form;

if the signal corresponding to the acknowledgment of the request has already been sent to the source fax machine and if the acknowledgement signal relayed from the destination fax machine to the first point of presence is received thereafter, enabling start of the fax transmission; and

if no acknowledgement signal is received from the destination fax machine at the first point of presence within the maximum allowable reception time, disabling start of the fax transmission.

2. The method according to claim 1, wherein the digital data link is a frame relay link.

3. The method according to claim 1, wherein the digital data link is an asynchronous transfer mode link.

4. A method for enabling and disabling a fax transmission between a source fax machine and a destination fax machine over a digital data link, comprising the steps of:

receiving a request for sending the fax transmission over the digital data link, the request being received at a first time;

determining a second time, later than the first time, at which an acknowledgement signal to the request must be received by the source fax machine in order to enable start of the fax transmission;

relaying the request to the destination fax machine over the digital data link;

if the acknowledgment signal has not been received from the destination fax machine at a third time which is after the first time but before the second time, sending a signal corresponding to the acknowledgment signal to the source fax machine, wherein the signal corresponding to the acknowledgement signal is a spoofing signal to maintain the link between the source fax machine and the destination fax machine;

if the acknowledgement signal is received from the destination fax machine at a fourth time after the third time at which the signal corresponding to the acknowledgement signal was sent to the source fax machine, enabling start of the fax transmission; and

if the acknowledgement signal is not received from the destination fax machine by the second time, disabling start of the fax transmission by sending a signal to the source fax machine that cancels the signal corresponding to the acknowledgement signal previously sent.

5. The method according to claim 4, wherein the request is relayed to the destination fax machine over the digital data link in one or more data packets.

6. The method according to claim 5, wherein the digital data link is a frame relay network.

7. A point of presence for providing a spoofing signal to maintain connection of a link between a source fax machine and a destination fax machine over a digital data network, comprising:

a modem connected to a local exchange carrier and configured to receive a request for fax transmission over the digital data network sent by the source fax machine;

a processor coupled to said modem and configured to determine a maximum allowable time at which an acknowledgement signal must be received by the source fax machine in order to maintain a fax session corresponding to the fax transmission;

a router coupled to said processor and configured to relay the request for fax transmission over the digital data network to the destination fax machine;

said processor configured to determine if the acknowledgement signal has been received from the destination fax machine;

said processor configured to send a first signal corresponding to the acknowledgement signal via the modem to the source fax machine before the maximum allowable time has elapsed in order to maintain the fax session irrespective of whether the acknowledgment signal has been received from the destination fax machine,

wherein if the processor has sent the signal corresponding to the acknowledgement signal to the source fax machine and if the maximum allowable time has elapsed without receiving the acknowledgement signal from the destination fax machine, the processor sends a second signal to the source fax machine via the modem to cancel the first signal and to end the fax session.

8. The system according to claim 7, wherein the request is relayed by the router in a packetized format.

9. The system according to claim 7, wherein the digital data network is a frame relay network.

10. The system according to claim 7, wherein the digital data network is an asynchronous transfer mode network.