Fax device, communication device, communication method and storage medium

Abstract

Fax device for conducting communication using a session established according to a Session Initiation Protocol (SIP), with: a transmission device for transmitting an INVITE signal, in which "image" is designated as a media type, in a case where an INVITE signal is received, in which "audio" is designated as a media type; a fax communication device for establishing an image session and executing a fax communication in the event that a successful response is received to the INVITE signal transmitted by the transmission device; and a call device for initiating call processing to call a user in the event that an error response is received to the INVITE signal transmitted by the transmission device.

Description

TECHNICAL FIELD

[0001] The present invention relates to a facsimile apparatus, a communication apparatus, a communication method and a storage medium. BACKGROUND TECHNOLOGY

[0002] In recent years, due to the widespread use of the Internet and IP phones, a method for conducting fax communication using an IP network as a communication path has been developed. A call control protocol such as SIP (Session Initiation Protocol) for establishing, modifying, and terminating a session for real-time communication has been standardized. Audio communication on a VoIP network, which uses VoIP (Voice over Internet Protocol) to conduct communication by accepting / receiving a modem signal as voice, has also begun to spread. Similarly, the T.38 protocol for converting a G3 fax signal (ITU-T Recommendation T.30)S into an IP message on an IP network and transmitting the IP message in real time, has been proposed, and an Internet fax device compliant with ITU-T Recommendation T.38 is on the market. Fax communication using this T.38 protocol has a bandwidth that can be smaller than that of audio communication on a VoIP network, which requires a voice band, and it does not need to modulate data into a modem signal, which provides an advantage in enabling high-speed communication.

[0003] Similarly, an IP-PBX (Internet Protocol Private Branch eXchange) is becoming widespread as a device for circuit switching IP telephone terminals in a private IP network. This IP-PBX is a device for implementing a private branch exchange (PBX) using IP telephones on an internal LAN, and it uses call control protocols such as SIP and H.323 to perform call control of the IP telephones, etc. A real-time Internet fax device uses SIP to obtain an IP address of a communication partner through this IP-PBX and performs P2P communication with the communication partner. Generally, when performing T.38 communication, a user refers to the SIP media type as "application" or "image" to perform communication, and refers to the SIP media type as "audio."“audio” to make a phone call.

[0004] IP-PBXs capable of performing T.38 communication include a device that, even in the case of performing T.38 communication, must start working when the media type is designated as "Audio" at the time of establishing a session using SIP, and then perform fax communication by changing the media type to "Image".

[0005] A Subscriber Line Interface Circuit (SLIC) module is also provided as a technology for setting up an IP phone. This module performs A / D conversion processing and telephone line emulation using an audio codec such as G.711. The SLIC module makes it possible to connect an analog telephone to an IP network without using a telephone line, thereby providing a function that emulates a telephone line, such as generating a ring signal and various types of telephone line tone signals (telephone switching).

[0006] Fig. Figure 3 is a diagram illustrating a conventional sequence for an incoming call.

[0007] When an IP phone using an SLIC module receives an INVITE signal from a sender to establish an audio session, the IP phone generates a ring signal for an analog phone connected to the SLIC module to generate a tone. The generated ring signal causes the analog phone's ringer to generate a tone. When a user picks up the analog phone, the SLIC module detects that the analog phone is off-hook, stops the ring signal, and transmits a success response (200 OK) to the sender. The sender returns an ACK. Accordingly, an audio session is established, and the user enters a conversational state.

[0008] JP 2011 114 672 A provides a conventional example for controlling incoming calls of an IP phone. According to this document, in a telephone network, an incoming call is first received by an interactive voice dialog system or voice server, and a ring tone is not played immediately after the incoming call is received. In the interactive voice dialog system or voice server, for each connection, a sender is notified of an authentication tone as an authentication tone necessary for the connection. This tone is obtained by superimposing random numbers, which are subject to random number processing each time, and background tones. A ring tone is played only for an incoming call in which a correct response value is received, and no ring tone is played otherwise.

[0009] In the following case, it is assumed that not only when a telephone call is made but also when a T.38 communication is made, an IP-PBX is used, which must start operating when a media type of "audio" is designated in the case of a session establishment request (INVITE signal) using SIP. The communication terminal on a receiving side cannot determine whether the incoming call is for a telephone call or a T.38 communication based on the session establishment request (INVITE signal). Therefore, a malfunction such that an incoming call is made to call a user even in the case of an incoming call for a T.38 communication may occur, and therefore a non-ringing state for incoming calls in a facsimile device becomes impossible.

[0010] There is also a real-time Internet fax device that, in addition to the T.38 communication function, supports an IP telephone function and a function for conducting audio communication on a VoIP network. Such a fax device requires incoming call control processing to select the most appropriate communication method based on the received session establishment request, so that it can also support the functions of a conventional G3 fax device on the IP network, including a telephone function that has a variety of reception modes in addition to the telephone function.

[0011] The document US 2010 / 0 278 172 A1 discloses an image communication device with a call connection control unit that establishes a session with a communication partner using an SIP message, and an image communication control unit that controls image communication, wherein (i) when the call connection control unit, as a calling subscriber, receives from a called subscriber an INVITE SIP message in which a T.38 communication and a first priority transport are specified, and if a second priority transport is set in the image communication control unit of the calling subscriber, the call connection control unit opens the second priority transport, and (ii) if no priority transport is set in the image communication control unit of the calling subscriber, the call connection control unit opens the first priority transport specified by the called subscriber and a T.38 communication using the open transport. SUMMARY OF THE INVENTION

[0012] An object of the present invention is to eliminate the aforementioned problems with the conventional technology. This object is achieved by a fax device, a communication device, a communication method, and a storage medium as defined in the claims.

[0013] A feature of the present invention is to provide a technique for enabling incoming calls to not generate ringing and to be performed appropriately even when it cannot be determined whether a telephone call or a fax communication is to be performed when a session establishment request is received.

[0014] According to one aspect of the present invention, there is provided a facsimile apparatus for performing communication using a session established according to a Session Initiation Protocol (SIP), comprising: transmitting means for transmitting an INVITE signal in which "image" is designated as a media type in a case of receiving an INVITE signal in which "audio" is designated as a media type; facsimile communication means for establishing an image session and performing facsimile communication in a case of a success response to the INVITE signal transmitted by the transmitting means; and calling means for starting call processing for calling a user in a case of an error response to the INVITE signal transmitted by the transmitting means.

[0015] According to another aspect of the present invention, there is provided a communication apparatus for performing communication using a session established according to a Session Initiation Protocol (SIP), comprising: transmitting means for transmitting an INVITE signal in which "image" is designated in a case of receiving an INVITE signal in which "audio" is designated; image communication means for performing image communication in a case of a success response to the INVITE signal transmitted by the transmitting means; and calling means for starting call processing for calling a user in a case of an error response to the INVITE signal transmitted by the transmitting means.

[0016] According to yet another aspect of the present invention, there is provided a communication device for performing communication using a session established according to a Session Initiation Protocol (SIP), comprising: transmitting means for transmitting an INVITE signal for changing a media type in a case that an INVITE signal is received; and calling means for starting call processing for calling a user in a case that an error response is made to the INVITE signal transmitted by the transmitting means.

[0017] According to yet another aspect of the present invention, there is provided a method for controlling a facsimile device to perform communication using a session established according to a Session Initiation Protocol (SIP), comprising: a transmission step of transmitting an INVITE signal in which "image" is designated as a media type in a case of receiving an INVITE signal in which "audio" is designated as a media type; a fax communication step of establishing an image session and performing fax communication in a case of a success response to the INVITE signal transmitted in the transmission step; and a calling step of starting call processing for calling a user in a case of an error response to the INVITE signal transmitted in the transmission step.

[0018] According to yet another aspect of the present invention, there is provided a communication method for performing communication using a session established according to a Session Initiation Protocol (SIP), comprising: a transmission step of transmitting an INVITE signal in which "image" is designated in a case of receiving an INVITE signal in which "audio" is designated; an image communication step of performing image communication in a case of a success response to the INVITE signal transmitted in the transmission step; and a calling step of starting call processing for calling a user in a case of an error response to the INVITE signal transmitted in the transmission step.

[0019] According to yet another aspect of the present invention, there is provided a communication method for performing communication using a session established according to a Session Initiation Protocol (SIP), comprising: a transmitting step of transmitting an INVITE signal for changing a media type in a case that an INVITE signal is received; and a calling step of starting call processing for calling a user in a case that an error response is made to the INVITE signal transmitted in the transmitting step.

[0020] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. SHORT DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Fig. 1 is a block diagram illustrating a configuration of a facsimile apparatus according to an embodiment of the present invention. Fig. 2 is a block diagram illustrating a software configuration of the facsimile apparatus according to the embodiment of the present invention. Fig. 3 is a sequence diagram illustrating a SIP protocol and a timing of processing for an incoming call when a signal arrives at an IP phone according to a conventional technique. Fig. 4 is a diagram illustrating a sequence in which a receiver executes incoming call processing for a telephone conversation according to the embodiment of the present invention. Fig. 5 is a flowchart for describing processing performed by the facsimile apparatus according to the present embodiment when a signal arrives. Fig. 6A and Fig. 6B are flowcharts for describing processing performed when the facsimile apparatus according to the embodiment of the present invention receives a session establishment request (INVITE signal). DESCRIPTION OF EMBODIMENTS

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the following embodiments are not intended to limit the claims of the present invention, and that not all of the combinations of aspects described in the following embodiments are necessarily required in view of the means for solving the problems according to the present invention.

[0023] Fig. 1 is a block diagram illustrating a configuration of a fax device according to an embodiment of the present invention. This fax device is a real-time Internet fax device that uses a SIP protocol to establish a call connection on an IP network, has an IP telephone function, and is capable of performing G3 fax communication on a VoIP network or fax communication compliant with ITU-T Recommendation T.38.

[0024] According to Fig. 1, a CPU 101 performs overall control of this device according to a program stored in a ROM 102. The ROM 102 has control programs for controlling the CPU 101, various types of data, and the like stored therein. A RAM 103 includes an SRAM and the like, and provides a work area in which various types of data are temporarily stored under operation of the CPU 101. An image memory 104 includes a DRAM and the like, and is used to store image data. A resolution converter 105 changes the resolution of image data. Here, the resolution converter 105 performs control to convert, for example, raster data in millimeters into raster data in inches. A codec 106 performs processing for encoding and decoding image data that is / are being processed or to be processed in this facsimile device. A real-time clock ora real-time clock (RTC) 107 measures a predetermined time period, the current date and time, and the like according to an instruction of the CPU 101.

[0025] A digital modem 108 modulates and encodes a process signal and image data from this fax device and transmits the digital data to an IP telephone line. A SLIC module 109 performs A / D conversion processing and telephone line emulation using an audio codec such as G.711. With this SLIC module 109, it is possible to connect a telephone 110 to an IP network without using a telephone line, thereby providing a function that modulates or emulates a telephone line, such as generating a ringing signal and various types of telephone line tone signals (telephone switching). The telephone 110 includes a handset for use during telephone conversation and has an answering function. A LAN I / F 111 controls communication with a network 112 such as a LAN. This network 112 is an IP network such as a private IP or NGN.

[0026] An image processor 113 performs correction processing on image data read by a scanner and outputs high-resolution image data. A sheet scanner 114 and a book scanner 115 are each equipped with a CS image sensor, a document transport mechanism, and the like, and are each configured to optically read a document, electronically generate image data, and output the generated image data. The sheet scanner 114 and the book scanner 115 can also read both sides of the document. An operation unit 116 is equipped with a keyboard, a display unit, and the like, and is configured to display a message or the like to a user and receive various types of input operations performed by the user.When the handset of the telephone 110 is removed from the cradle, the operating unit 116 displays a message indicating that real-time dialing is possible, and when the telephone 110 is removed from the cradle, the display unit 116 indicates that communication is in progress and a communication reservation is acceptable.

[0027] A line buffer 117 is used when controlling image data transmission and stores image data in units of lines. A print buffer 118 is a one-page buffer memory that stores print data to be output to a printer 119. The printer 119 is, for example, a laser printer, an inkjet printer, or the like, which prints received image or file data on plain paper. The printer 119 can also perform double-sided printing.

[0028] Fig. 2 is a block diagram illustrating a software configuration of the facsimile apparatus according to the embodiment of the present invention.

[0029] In the case of audio communication on a VoIP network, a user uses the operation unit 116 to select the audio communication on a VoIP network type for fax communication. In this case, a call / talk job of an IP phone is generated by a job control unit 201, and a line control unit 203 is notified of the generated call / talk job via a communication manager 202. The line control unit 203 instructs a protocol stack 205 to connect to the communication partner using a SIP protocol since the call was originated by the IP phone. A SIP message or signal generated by the protocol stack 205 is transmitted to a LAN (IP network) 112 via a NIC 206.When establishing an audio session with the communication partner using the SIP protocol, a voice input from the telephone 110 is encoded by the SLIC module 109, and the voice is transmitted to the IP network 112 using the RTP protocol of the protocol stack 205. When the operation unit 116 instructs to start a transmission, a fax communication control unit 204 starts a fax communication, and the generated fax process signal and image data are transmitted to the communication partner via the digital modem 108 using the RTP protocol in the protocol stack 205.

[0030] Also, in the case of fax transmission using the T.38 protocol (T.38 transmission), a function for selecting an IP network, an SIP protocol, or the like is applied by the operation unit 116 to select a T.38 transmission. A T.38 transmission job is generated by the job control unit 201, and a notification is sent to the communication manager 202. The communication manager 202 instructs the protocol stack 205, via the line control unit 203, to connect to the communication partner using the SIP protocol. An SIP message or signal generated by the protocol stack 205 is transmitted to the LAN (IP network) 112 via the NIC 206. Accordingly, when a session is established with the communication partner using the SIP protocol, the communication manager 202 performs fax operations with respect to the connected communication partner using the T.38 protocol.

[0031] Fig. 4 is a diagram illustrating a sequence in which a receiver executes incoming call processing for a telephone conversation according to the embodiment of the present invention.

[0032] In step S401, a sender transmits a session establishment request (INVITE signal) to the communication partner via an IP-PBX to establish a session of the media type "audio" in order to conduct a telephone conversation. Accordingly, in step S402, the receiver receives the session establishment request (INVITE signal) to establish a session of the media type "audio." Here, processing for an incoming call is not immediately executed; instead, a preliminary response (180 Ringing) is transmitted in step S403, and a success response (200 OK) is transmitted in step S404. Then, in step 405, the receiver receives an ACK signal from the sender, and an audio session is established.

[0033] Next, in step S406, the receiver transmits to the sender a session change request (reINVITE signal) to change the session to a session of the media type "image" to determine whether the incoming call is for a telephone conversation or a communication using the T.38 protocol (T.38 communication).

[0034] In this case, since the sender intends to make a telephone call, an error response (488 Not Acceptable Here) is issued in response to the session change request for a T.38 communication, which is for changing the session to a session of the "image" media type, in step S407. Accordingly, the receiver receives the error response (488 Not Acceptable Here) from the sender in step S408 and determines that the incoming call is not for a T.38 communication but for a telephone call. Then, incoming call processing for calling a user and processing for outputting a pseudo ringback tone are executed, the pseudo ringback tone indicating to the sender that a call is in progress.Then, when the user removes the telephone 110 from the cradle to answer the call, the receiver stops executing the incoming call processing and emitting the pseudo ringback tone in step S409, resulting in a call state. When the telephone call ends and the receiver places the telephone 110 on the cradle, a BYE signal is transmitted to the sender in step S410. If a success response (200 OK) is received from the sender, the session ends in step S411.

[0035] Fig. 5 is a flowchart for describing processing performed by the facsimile device according to the present embodiment when a signal arrives. Here, incoming call processing is executed when a telephone conversation is intended, and T.38 communication is executed when T.38 communication is intended. Note that a program for executing this processing is stored in the ROM 102, and the processing described by this flowchart is executed by the CPU 101 executing this program.

[0036] First, if the CPU 101 receives a session establishment request (INVITE signal) in step S501, processing proceeds to step S502, and the CPU 101 establishes a connection in a media session of the media type designated by the INVITE signal. Next, processing proceeds to step S503, and the CPU 101 determines whether the designated media type is "image" or "application." If so, processing proceeds to step S506, and the CPU 101 executes fax reception processing using the T.38 protocol. On the other hand, if it is determined in step S503 that the designated media type is "audio," processing proceeds to step S504. In step S504, the CPU 101 transmits a session change request (reINVITE signal) to the sender to change the session to a session of the media type “image”, and asks the sender whether the incoming call is for a telephone call or a T.38 communication.

[0037] Next, processing proceeds to step S505. If a success response (200 OK) is received to the session change request in step S504, processing proceeds to step S506, and the CPU 101 executes fax reception processing using the T.38 protocol. On the other hand, if the sender responds to the session change request with an error response in step S505, it is determined that the incoming call is for a telephone conversation, and processing proceeds to step S507. In step S507, the CPU 101 starts incoming call processing for calling a user and processing for outputting a pseudo ringback tone that indicates to the sender that a call is in progress.

[0038] Next, processing proceeds to step S508. If the CPU 101 detects that the user has removed the telephone 110 from the cradle, processing proceeds to step S509. The CPU 101 stops the incoming call processing and the pseudo ringback tone processing. Then, processing proceeds to step S510 and enters a talk state. Next, if the CPU 101 detects that the telephone 110 is in an on-hook state in step S511, a BYE signal is transmitted, and the session ends.

[0039] As described above, the facsimile device that performs connection / call control using SIP and includes a T.38 communication function for realizing an IP telephone function, upon receiving a session establishment request (INVITE signal) for establishing a session of the "audio" media type, determines whether a telephone call or T.38 communication is intended. If it is determined that a T.38 communication is intended, fax reception processing is executed using the T.38 protocol. If it is determined that a telephone call is intended, incoming call processing for calling a user is executed, and the device enters a conversation state.

[0040] Fig. 6A and Fig. 6B are flowcharts for describing processing performed when the facsimile device according to the embodiment of the present invention receives a session establishment request (INVITE signal). Note that a program for executing this processing is stored in the ROM 102, and the processing described by the flowcharts is executed by the CPU 101 executing this program.

[0041] This processing starts with receipt of the session establishment request (INVITE signal). First, the CPU 101 determines the reception mode of its own device in step S601. If the reception mode is an automatic reception mode or a fax / telephone automatic switching mode, the processing proceeds to step S606. In step S606, the CPU 101 notifies the sender of a success response (200 OK) without executing the incoming call processing. On the other hand, if it is determined in step S601 that the reception mode of the device is a manual reception mode or an answering machine connection mode, the processing proceeds to step S602, and the CPU 101 begins the incoming call processing. The processing further proceeds to step S603, and the CPU 101 notifies the sender of a preliminary response (180 Ringing).If in step S604 the connected telephone answers the incoming call and it is detected that the telephone is off-hook, then the processing proceeds to step S605, and the CPU 101 stops the incoming call processing, and the processing further proceeds to step S606, and a success response is reported to the sender (200 OK).

[0042] Next, processing proceeds to step S607, and a session of the media type "audio" is established when the CPU 101 receives an ACK signal from the sender. Then, processing proceeds to step S608, and the CPU 101 transmits to the sender a session change request (reINVITE signal) for changing the session to a media type "image" session to determine whether a telephone conversation or a fax communication using the T.38 protocol is intended. Then, processing proceeds to step S609, where it is determined what a response to the session change request (reINVITE signal) for changing the session to a media type "image" session is. If it is determined that the response is a success response (200 OK), processing proceeds to step S610 ( Fig. 6B), the CPU 101 changes the session to a session of the media type "image" and executes the fax reception processing using the T.38 protocol.

[0043] On the other hand, if an error response is received in step S609, then it is determined that no fax communication using the T.38 protocol is intended, but a telephone call or fax communication on a VoIP network is intended, and the processing proceeds to step S611 ( Fig. 6B). In step S611, the CPU 101 determines the reception mode of its own device to execute appropriate processing for the corresponding reception mode while maintaining the session of the media type "audio." If the reception mode is manual reception, processing proceeds to step S612 and enters the talk state.

[0044] Also, if it is determined in step S611 that the reception mode is the answering machine connection mode, processing proceeds to step S613, and the CPU 101 monitors a CNG signal transmitted from the sender. If the CNG signal is detected in step S613, processing proceeds to step S615, and the CPU 101 performs fax reception using audio communication on the VoIP network. On the other hand, if no CNG signal is detected in step S613 and the connected telephone 110 is in an on-hook state in step S614, a BYE signal is notified to the sender and the session ends.

[0045] Alternatively, when it is determined in step S611 that the reception mode is the automatic reception mode, the processing proceeds to step S615, and the CPU 101 executes fax reception processing using audio communication on the VoIP network without executing the incoming call processing.

[0046] Further alternatively, if it is determined in step S611 that the reception mode is the FAX / TEL automatic changeover mode, processing proceeds to step S616, and CPU 101 sets a predetermined time period for the real-time clock 107. Then, processing proceeds to step S617, and CPU 101 starts processing for outputting a pseudo ringback tone to the transmitter. Then, processing proceeds to step S618, and it is determined whether or not a CNG signal is detected. If a CNG signal is detected, processing proceeds to step S620, in which it is determined whether or not an off-hook state of the telephone 110 is detected. If it is determined in step S620 that an off-hook state is detected, processing proceeds to step S621, and CPU 101 determines whether measurement of a predetermined time period by the real-time clock 107 is required.the real-time encoder 107 is completed or not, that is, whether timeout is detected or not. If it is determined that timeout is detected, the processing proceeds to step S622, and the CPU 101 starts incoming call processing for calling a user, and the processing proceeds to step S618. In step S618, if a CNG signal is detected, the processing proceeds to step S619, and the CPU 101 stops the incoming call processing and the processing for outputting a pseudo ringback tone. Then, the processing proceeds to step S615, and the CPU 101 executes fax reception processing using audio communication on the VoIP network.

[0047] On the other hand, if no CNG signal is detected in step S618 and the telephone 110 is taken off the hook in response to an incoming call in step S620, the processing proceeds to step S623, and the CPU 101 stops the incoming call processing and the pseudo ringback tone output processing. Then, the processing transitions to a talk state in step S612.

[0048] As described above, the fax device according to the present embodiment, which performs call control using SIP, has an IP telephone function and a function for performing audio communication on a VoIP network, and includes a plurality of reception modes for fax reception, can perform the following operations: (1) A process in which an audio session is established if a session establishment request for establishing a session of the media type "audio" is received, and then an image session establishment request is transmitted to perform T.38 communication. Then, if a success response is received, an image session is established and fax communication is performed using T.38 processes (step S610). (2) In the case of an automatic reception mode in which audio communication is automatically performed on the VoIP network, the success response upon receipt of the session establishment request is transmitted using SIP, and no processing is performed for an incoming call even after the audio session is established. (3) In the case of a manual reception mode in which reception is performed by a user's operation, processing for an incoming call is performed upon receiving the session establishment request using SIP, and the incoming call is stopped when the connected telephone is picked up, and call processing is performed. (4) In the case of an answering machine connection mode in which the operation of a connected answering machine that is currently answering is switched to a reception mode upon detection of a fax signal, incoming call processing is performed upon receipt of the session establishment request using SIP. Also, a CNG signal is monitored after off-hook operation of the connected answering machine is detected, and when the CNG signal is detected, G3 fax reception is performed using audio communication on a VoIP network (step S615). (5) In the case of a FAX / TEL automatic switching mode, in which it is automatically determined whether a fax communication or a telephone conversation is intended to perform corresponding telephone conversation processing and reception processing, the session establishment request for establishing a session of the media type "audio" is received, the success response is transmitted, and an audio session is established. Then, detection of a CNG signal starts, and if no CNG signal could be detected within a preset time period, incoming call processing is executed (step S622). If a CNG signal is detected, G3 fax reception using audio communication is performed on the VoIP network (step S615). Further examples

[0049] Aspects of the present invention can also be implemented by a computer of a system or device (or components such as a CPU or MPU) that reads and executes a program recorded on a storage device to perform the functions of the above-described embodiments, as well as by a method whose steps are performed by a computer of a system or device, for example, by reading and executing a program recorded on a storage device to perform the functions of the above-described embodiments. For this purpose, the program is provided to the computer, for example, via a network or from a recording medium of various types (for example, a computer-readable medium) serving as the storage device.

[0050] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation to encompass all such modifications and equivalent structures and functions.

Claims

[1] A fax device for conducting communication using a session established in accordance with a session initiation protocol (SIP), comprising: a transmission device for transmitting an INVITE signal in which “image” is designated as a media type in a case of receiving an INVITE signal in which “audio” is designated as a media type; a fax communication device for establishing an image session and executing a fax communication in case of a success response to the INVITE signal transmitted by the transmission device; and a calling device for starting call processing to call a user in a case that an error response is made to the INVITE signal transmitted by the transmission device. [2] Fax device according to claim 1, additionally comprising: a detecting device for detecting that a telephone is in an off-hook state in response to the call processing; and an audio communication device for establishing an audio session and performing an audio communication in a case that the detecting device detects that the telephone is in an off-hook state. [3] A facsimile apparatus according to claim 1, wherein in a case of receiving an INVITE signal in which “image” or “application” is designated as a media type, the transmitting means does not transmit the INVITE signal. [4] Fax device according to claim 1, additionally comprising: a setting device for setting a reception mode, wherein, in a case where the reception mode set by the setting means is a first reception mode, the calling means starts the call processing in a case that an error response is made to the INVITE signal transmitted by the transmitting means, and in a case where the reception mode set by the setting means is a second reception mode, the calling means starts the call processing before the transmitting means transmits the INVITE signal. [5] A communication device for performing communication using a session established according to a session initiation protocol (SIP), comprising: a transmission device for transmitting an INVITE signal in which “image” is designated in a case of receiving an INVITE signal in which “audio” is designated; an image communication device for executing image communication in a case where a success response is made to the INVITE signal transmitted by the transmission device; and a calling device for starting call processing to call a user in a case that an error response is made to the INVITE signal transmitted by the transmission device. [6] Communication device according to claim 5, additionally comprising: a detecting device for detecting that a telephone is in an off-hook state in response to the call processing; and an audio communication device for establishing an audio session and performing an audio communication in a case that the detecting device detects that the telephone is in an off-hook state. [7] The communication device according to claim 5, wherein in a case where an INVITE signal is received in which “image” or “application” is designated, the transmitting means does not transmit the INVITE signal. [8] Communication device according to claim 5, additionally comprising: a setting device for setting a reception mode, wherein, in a case where the reception mode set by the setting means is a first reception mode, the calling means starts the call processing in a case that an error response is made to the INVITE signal transmitted by the transmitting means, and in a case where the reception mode set by the setting means is a second reception mode, the calling means starts the call processing before the transmitting means transmits the INVITE signal. [9] A communication device for performing communication using a session established according to a session initiation protocol (SIP), comprising: a transmission device for transmitting an INVITE signal for changing a media type in case that an INVITE signal is received; and a calling device for starting call processing to call a user in a case that an error response is made to the INVITE signal transmitted by the transmission device. [10] Communication device according to claim 9, additionally comprising: a facsimile communication device for executing a facsimile communication in a case that a success response is made to the INVITE signal transmitted by the transmission device. [11] Communication device according to claim 9, additionally comprising: a detecting device for detecting that a telephone is in an off-hook state in response to the call processing; and an audio communication device for performing an audio communication in a case that the detecting device detects that the telephone is in an off-hook state. [12] The communication device according to claim 9, wherein in a case where an INVITE signal is received in which “image” or “application” is designated as a media type, the transmission device does not transmit the INVITE signal. [13] Communication device according to claim 9, additionally comprising: a setting device for setting a reception mode, wherein, in a case where the reception mode set by the setting means is a first reception mode, the calling means starts the call processing in a case that an error response is made to the INVITE signal transmitted by the transmitting means, and in a case where the reception mode set by the setting means is a second reception mode, the calling means starts the call processing before the transmitting means transmits the INVITE signal. [14] A method for controlling a fax device to perform communication using a session established according to a session initiation protocol (SIP), comprising: a transmission step of transmitting an INVITE signal in which "image" is designated as a media type in a case of receiving an INVITE signal in which "audio" is designated as a media type; a fax communication step of establishing an image session and executing a fax communication in a case where a success response is made to the INVITE signal transmitted in the transmission step; and a calling step of starting call processing for calling a user in a case that an error response is made to the INVITE signal transmitted in the transmitting step. [15] A communication method for performing communication using a session established in accordance with a Session Initiation Protocol (SIP), comprising: a transmission step of transmitting an INVITE signal in which “image” is designated in a case of receiving an INVITE signal in which “audio” is designated; an image communication step of executing image communication in a case where a success response is made to the INVITE signal transmitted in the transmission step; and a calling step of starting call processing for calling a user in a case that an error response is made to the INVITE signal transmitted in the transmitting step. [16] A communication method for performing communication using a session established in accordance with a Session Initiation Protocol (SIP), comprising: a transmission step of transmitting an INVITE signal for changing a media type in a case that an INVITE signal is received; and a calling step of starting call processing for calling a user in a case that an error response is made to the INVITE signal transmitted in the transmitting step. [17] A non-transitory computer-readable storage medium storing a program for causing a computer to carry out the method according to claim 14. [18] A non-transitory computer-readable storage medium storing a program for causing a computer to carry out the method according to claim 15. [19] A non-transitory computer-readable storage medium storing a program for causing a computer to carry out the method according to claim 16.

Images