Sg3-to-g3 fax spoof
AssigneeCisco Technology, Inc.
InventorsHanh Huu Luong, Brooks Stevens Read
Life of this patent
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Abstract
In one embodiment, an originating gateway receives a call menu (CM) signal from an originating fax machine. The CM signal may have been generated in response to an ANSam signal from a terminating fax machine. The originating gateway suppresses the CM signal after a preamble of the CM signal and generates a modified JM signal in response to receiving the CM signal. The modified JM signal indicates that V.34 half-duplex modulation is not an option. The originating gateway transmits the modified JM signal to the originating fax machine, which allows the transmission to continue across an unenhanced T.38 fax relay.
Claims20
A method comprising:
- receiving a Call Menu (CM) signal from an originating fax machine;
- suppressing the CM signal after a preamble of the CM signal;
- generating a modified Joint Menu (JM) signal in response to receiving the CM signal, wherein the modified JM signal indicates that V.34 half-duplex modulation is not an option;
- and
- transmitting the modified JM signal to the originating fax machine.
Logic encoded in one or more tangible media for execution and when executed operable to:
- receive a first Call Menu (CM) signal from an originating fax machine;
- suppress the CM signal after a preamble of the CM signal;
- generate a modified Joint Menu (JM) signal in response to receiving the CM signal, wherein the modified JM signal indicates unavailability of V.34 half-duplex;
- and
- transmit the modified JM signal to the originating fax machine.
A device comprising:
- a time division multiplexing (TDM) interface;
- and
- a detector in a packet-based channel at the TDM interface, wherein the detector monitors for V.8 Call Menu (CM) sequences that indicate fax operation is requested and monitors for a V.21 flags detected peer-to-peer message from the remote gateway,
- wherein the detector, in response to detecting a V.8 CM sequence, transmits a V.8 Joint Menu (JM) signal to an originating fax machine via the TDM interface, the V.8 JM signal excluding an indication of SG3 fax modulation capabilities.
Dependencies are inferred from the claim text.