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US 8,526,447 B1Granted
H.323 to SIP fax interworking
AssigneeCisco Technology, Inc.
InventorsParameswaran Kumarasamy, Mohammed Taher Shaikh, Paul Chu
Life of this patent
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Abstract
A network device has a H.323 interface to communicate under a H.323 standard of the International Telecommunications Union. The device also has a Session Initiation Protocol (SIP) interface. A processor converts signaling messages between H.323 and Session Initiation Protocol to establish a fax session for communication of packetized fax signals and data.
Claims20
A device for fax interworking, the device comprising:
- an H.323 interface;
- a Session Initiation Protocol (SIP) interface;
- and
- a processor operable to:
- establish a voice call between an H.323 endpoint and a SIP endpoint;
- transmit a fax mode request message to the H.323 endpoint through the H.323 interface in response to receiving a fax invite message from the SIP endpoint through the SIP interface;
- close any open logical channels for voice between the H.323 endpoint;
- open a logical channel for fax between the H.323 endpoint by exchanging messages with the H.323 endpoint, the messages comprising an Internet Protocol (IP) address and a Real-Time Transport Protocol Control Protocol (RTCP) port;
- establish a fax call between the H.323 endpoint and the SIP endpoint after opening the logical channel for fax;
- and
- end the fax call by switching back to the voice call, wherein switching back to the voice call comprises:
- transmitting a voice mode request message to the H.323 endpoint through the H.323 interface in response to receiving a voice invite message from the SIP endpoint through the SIP interface;
- closing the logical channel for fax between the H.323 endpoint;
- and
- opening a logical channel for voice between the H.323 endpoint.
12 more elements
A method of fax interworking, the method comprising:
- establishing a voice call between an H.323 endpoint and a Session Initiation Protocol (SIP) endpoint;
- transmitting a fax mode request message to the H.323 endpoint through an H.323 interface in response to receiving a fax invite message from the SIP endpoint through SIP interface;
- closing any open logical channels for voice between the H.323 endpoint;
- opening a logical channel for fax between the H.323 endpoint by exchanging messages with the H.323 endpoint, the messages comprising an Internet Protocol (IP) address and a Real-Time Transport Protocol Control Protocol (RTCP) port;
- communicating packetized fax media via a fax call between the H.323 endpoint and the SIP endpoint;
- and
- ending the fax call by switching back to the voice call, wherein switching back to the voice call comprises:
- transmitting a voice mode request message to the H.323 endpoint through the H.323 interface in response to receiving a voice invite message from the SIP endpoint through the SIP interface;
- closing the logical channel for fax between the H.323 endpoint;
- and
- opening a logical channel for voice between the H.323 endpoint.
8 more elements
A device for fax interworking, the device comprising:
- means for interfacing according to H.323;
- means for interfacing according to Session Initiation Protocol (SIP);
- means for establishing a voice call between an H.323 endpoint and a SIP endpoint;
- means for transmitting a fax mode request message to the H.323 endpoint, by way of the means for interfacing according to H.323, in response to receiving a fax invite message from the SIP endpoint, by way of the means for interfacing according to SIP;
- means for closing any open logical channels for voice between the H.323 endpoint;
- means for opening a logical channel for fax between the H.323 endpoint by exchanging messages with the H.323 endpoint, the messages comprising an Internet Protocol (IP) address and a Real-Time Transport Protocol Control Protocol (RTCP) port;
- means for establishing a fax call between the H.323 endpoint and the SIP endpoint after opening the logical channel for fax;
- and
- means for ending the fax call by switching back to the voice call, wherein switching back to the voice call comprises:
- transmitting a voice mode request message to the H.323 endpoint through the H.323 interface in response to receiving a voice invite message from the SIP endpoint through the SIP interface;
- closing the logical channel for fax between the H.323 endpoint;
- and
- opening a logical channel for voice between the H.323 endpoint.
10 more elements
A non-transitory computer-readable media including code that, when executed on a computer, causes the computer to:
- establish a voice call between an H.323 endpoint and a Session Initiation Protocol (SIP) endpoint;
- transmit a fax mode request message to the H.323 endpoint through an H.323 interface in response to receiving a fax invite message from the SIP endpoint through SIP interface;
- close any open logical channels for voice between the H.323 endpoint;
- open a logical channel for fax between the H.323 endpoint by exchanging messages with the H.323 endpoint, the messages comprising an Internet Protocol (IP) address and a Real-Time Transport Protocol Control Protocol (RTCP) port;
- and
- communicate packetized fax media via a fax call between the H.323 endpoint and the SIP endpoint;
- and
- end the fax call by switching back to the voice call, wherein switching back to the voice call comprises:
- transmitting a voice mode request message to the H.323 endpoint through the H.323 interface in response to receiving a voice invite message from the SIP endpoint through the SIP interface;
- closing the logical channel for fax between the H.323 endpoint;
- and
- opening a logical channel for voice between the H.323 endpoint.
9 more elements
Dependencies are inferred from the claim text.