Real-Time Facsimile Transmission Over a Packet Network

• US 20110109936A1
• Filed: 11/10/2010
• Published: 05/12/2011
• Est. Priority Date: 11/10/2009
• Status: Active Grant

• Current Assignee: NetGen Communications, Inc.
• Original Assignee: NetGen Communications, Inc.
• Inventors: Schornak, Clifford J., Coffee, Michael B.
• Granted Patent: US 9,094,419 B2
• Time in Patent Office: Days
• US Class Current: 358/1.15
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/40 Support for services or applications
• CPC Class Codes: H04N 1/00214 details of transmission
• CPC Class Codes: H04N 1/0022 involving facsimile protocols or a combination of facsimile protocols and computer data transmission protocols
• CPC Class Codes: H04N 2201/0015 Control of image communication with the connected apparatus, e.g. signalling capability
• CPC Class Codes: H04N 2201/0024 Converting image communication control signals, e.g. group 3 facsimile protocol signals, to non-image communication control signals or vice versa

Abstract

Various methods and systems are provided for real-time facsimile (fax) transmission over a packet network. In one embodiment, among others, a method includes monitoring fax communications across a pass-through connection and controlling transfer of the fax communications to a fax-relay protocol connection based at least in part upon the monitored fax communications. In another embodiment, a method includes monitoring a state of a state machine communicating over a pass-through connection and, responsive to a re-invite to the fax-relay protocol, transferring from the pass-through connection to a fax-relay protocol connection based at least in part upon the state of the state machine.

Claims

1. A gateway, comprising:

a modem in communication with an endpoint fax terminal; and

a state observer configured to;

monitor communications of the endpoint fax terminal across a pass-through connection, the monitored communications indicating a state of the endpoint fax terminal; and

control transfer of the endpoint fax terminal communications from the pass-through connection to a fax-relay protocol connection based at least in part upon the monitored communications.

2. The gateway of claim 1, wherein the fax-relay protocol connection is a T.38 connection.

3. The gateway of claim 1, wherein the monitored communications include V.21 flags.

4. The gateway of claim 1, wherein the state observer includes a current observer state associated with the state of the endpoint fax terminal, the current observer state based at least in part upon the monitored communications.

5. The gateway of claim 4, wherein the state observer is configured to transition from the current observer state to a subsequent observer state based at least in part upon the monitored communications.

6. The gateway of claim 4, wherein the state observer is configured to allow acceptance of a re-invite to the fax-relay protocol by the gateway based upon the current observer state, acceptance of the re-invite to the fax-relay protocol initiating transfer of the endpoint fax terminal communications from the pass-through connection to the fax-relay protocol connection.

7. The gateway of claim 6, wherein the gateway is configured to suppress a digital identification signal (DIS) if the re-invite to the fax-relay protocol has not been accepted.

8. The gateway of claim 6, wherein the gateway is configured to spoof a fax call menu (CM) if the re-invite to the fax-relay protocol has not been accepted.

9. The gateway of claim 4, wherein the state observer is configured to allow initiation of a re-invite to the fax-relay protocol by the gateway based upon the current observer state, the re-invite to the fax-relay protocol requesting transfer of the endpoint fax terminal communications from the pass-through connection to the fax-relay protocol connection.

10. A fax server, comprising:

a virtual endpoint fax terminal including a fax application and a T.30 subsystem; and

a state observer configured to;

monitor a state of the virtual endpoint fax terminal based at least in part upon indications from the T.30 subsystem and a signaling entity; and

control transfer of communications of the virtual endpoint fax terminal from a pass-through connection to a fax-relay protocol connection based at least in part upon the indications from the T.30 subsystem and the signaling entity.

11. The fax server of claim 10, wherein the fax-relay protocol connection is a T.38 connection.

12. The fax server of claim 10, wherein the state observer includes a current observer state associated with a state of the endpoint fax terminal, the current observer state based at least in part upon the indications from the T.30 subsystem and the signaling entity.

13. The fax server of claim 12, wherein the state observer is configured to transition from the current observer state to a subsequent observer state based at least in part upon the indications from the T.30 subsystem and the signaling entity.

14. The fax server of claim 12, wherein the state observer is configured to allow acceptance of a re-invite to the fax-relay protocol by the fax server based upon the current observer state, acceptance of the re-invite to the fax-relay protocol initiating transfer of the endpoint fax terminal communications from the pass-through connection to the fax-relay protocol connection.

15. The fax server of claim 12, wherein the state observer is configured to allow initiation of a re-invite to the fax-relay protocol by the fax server based upon the current observer state, the re-invite to the fax-relay protocol requesting transfer of the endpoint fax terminal communications from the pass-through connection to the fax-relay protocol connection.

16. The fax server of claim 15, wherein the fax server is configured to suppress a digital identification signal if the re-invite to the fax-relay protocol has not been accepted.

17. The fax server of claim 15, wherein the fax server is configured to spoof a fax call menu if the re-invite to the fax-relay protocol has not been accepted.

18. The fax server of claim 10, wherein the signaling entity is a SIP entity.

19. A method, comprising:

monitoring fax communications across a G.711 pass-through connection; and

controlling transfer of the fax communications from the G.711 pass-through connection to a fax-relay protocol connection based at least in part upon the monitored fax communications.

20. The method of claim 19, further comprising determining a current state based at least in part upon the monitored fax communications.

21. The method of claim 20, wherein the current state is associated with a state of an endpoint fax terminal communicating across the G.711 pass-through connection.

22. The method of claim 20, wherein the current state is associated with a state of a fax application communicating across the G.711 pass-through connection.

23. The method of claim 20, wherein transfer of the fax communications is controlled based at least in part upon the current state.

24. The method of claim 20, further comprising:

receiving a re-invite to the fax-relay protocol requesting transfer of the fax communications from the G.711 pass-through connection to the fax-relay protocol connection; and

accepting the re-invite to the fax-relay protocol to initiate transfer from the G.711 pass-through connection to the fax-relay protocol connection based at least in part upon the current state.

25. The method of claim 20, further comprising:

receiving a re-invite to the fax-relay protocol requesting transfer of the fax communications from the G.711 pass-through connection to the fax-relay protocol connection; and

not accepting the re-invite to the fax-relay protocol to prevent transfer from the G.711 pass-through connection to the fax-relay protocol connection based at least in part upon the current state.

26. The method of claim 20, further comprising sending a re-invite to the fax-relay protocol based at least in part upon the current state, the re-invite to the fax-relay protocol requesting transfer of the fax communications from the G.711 pass-through connection to the fax-relay protocol connection.

27. The fax server of claim 26, further comprising suppressing a digital identification signal (DIS) if the re-invite to the fax-relay protocol has not been accepted.

28. The fax server of claim 26, further comprising spoofing a fax call menu (CM) if the re-invite to the fax-relay protocol has not been accepted.

29. A method, comprising:

monitoring a state of a state machine communicating over a pass-through connection; and

transferring from the pass-through connection to a fax-relay protocol connection based at least in part upon the state of the state machine.

30. The method of claim 29, wherein transferring from the pass-through connection to a fax-relay protocol connection is in response to a re-invite to the fax-relay protocol.

31. The method of claim 29, wherein transferring from the pass-through connection to a fax-relay protocol connection is in response to an acceptance of a re-invite to the fax-relay protocol.

32. The method of claim 29, wherein monitoring the state of the state machine comprises:

monitoring state machine communications across the pass-through connection; and

determining a current state based at least in part upon the monitored state machine communications.

33. The method of claim 29, further comprising:

receiving the re-invite to the fax-relay protocol requesting transfer from the pass-through connection to the fax-relay protocol connection; and

accepting the re-invite to the fax-relay protocol to initiate transfer based at least in part upon the state of the state machine.

34. The method of claim 29, further comprising sending the re-invite to the fax-relay protocol based at least in part upon the state of the state machine, the re-invite to the fax-relay protocol requesting transfer from the pass-through connection to the fax-relay protocol connection.

35. A method, comprising:

monitoring a fax session across a G.711 pass-through connection, the fax session including a plurality of packets communicated across the G.711 pass-through connection;

determining if a communicated packet includes a V.21 frame that is not a digital command signal (DCS); and

providing an indicator to reset a jitter buffer associated with the G.711 pass-through connection.

36. The method of claim 35, wherein the jitter buffer is in a gateway in communication with an endpoint fax terminal.

37. The method of claim 35, wherein the jitter buffer is in a fax server.

38. A method, comprising:

monitoring a fax session across a G.711 pass-through connection using the V.34 modulation scheme, the fax session including a plurality of packets communicated across the G.711 pass-through connection;

determining if a communicated packet includes a high-band QAM signal termination or a low-band QAM signal termination; and

providing an indicator to reset a jitter buffer associated with the G.711 pass-through connection.

39. The method of claim 38, further comprising clearing the indicator prior to the start of a subsequent signal.

40. The method of claim 38, wherein the jitter buffer is in a gateway in communication with an endpoint fax terminal.

41. The method of claim 38, wherein the jitter buffer is in a fax server.

42. A method, comprising:

monitoring a fax session across a G.711 media stream, the fax session including a plurality of packets communicated across the G.711 media stream;

determining that the fax session is using a V.8 specification to negotiate the fax session; and

corrupting the media stream to inhibit the V.8 negotiation for sufficient time to allow a call control entity to negotiate a transition to a fax-relay protocol.

43. The method of claim 42, wherein the method is independent of call control procedures implemented by an on-ramp gateway or an off-ramp gateway.