Multiplex communications – Special services – Special feature of multiplex telephone terminal
Patent
1996-07-23
1998-04-14
Safourek, Benedict V.
Multiplex communications
Special services
Special feature of multiplex telephone terminal
370463, 370465, 348 14, H04N 714
Patent
active
057401632
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a dual-mode visiophone terminal for digital or switched telephone networks. Its is applicable in the field of transmission and storage of audio and video data.
DESCRIPTION OF THE PRIOR ART
Present static telephone answering/recording machines use a system of compression of the digital audio signal received in which the compressed signal is stored in RAM. The total duration or number of the messages recorded depends on the compression rate of the audio signal. Silent periods can be used to economize memory. A similar technique for images does not exist in the case of visiophone calls, which is the main reason why the present video compression standard, defined by CCITT recommendation H.261, does not provide for economic storage of video in memory.
SUMMARY OF THE INVENTION
The present invention overcomes these disadvantages.
The object of the invention is a dual-mode visiophone terminal for use on an integrated services digital network (ISDN) or a switched telephone network (STN), including at least one audio equipment and one video equipment respectively connected to an ISDN via a dual-mode ISDN/STN audio coder/decoder incorporating an ISDN audio coder, an ISDN audio decoder, an STN audio coder and an STN audio decoder, and via a dual-mode ISDN/STN video coder/decoder incorporating an ISDN video coder, an ISDN video decoder, an STN video coder, and an STN video decoder, wherein in order to provide an answering/recording function in said visiophone terminal a RAM memory is used to store audiovisual messages in STN mode, and wherein the outputs of the ISDN audio and video decoders are connected respectively to the inputs of the STN audio and video coders in order to record in the RAM an audiovisual message sent by a calling party via a remote terminal, and wherein the outputs of the STN audio and video decoders are connected respectively to the inputs of the ISDN audio and video coders in order to send an audiovisual message, stored in the RAM, inviting said calling party to leave a message.
The invention has the advantage that it enables an answering/recording function to be incorporated directly and inexpensively in a dual-mode visiophone terminal, that is capable of sending an invitation to leave a message and of receiving and storing this message in audio and video form, while optimizing the quantity of RAM required.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and other advantages and characteristics will become clear on reading the following description making reference to the appended figures, of which:
FIG. 1 is a block diagram of a dual-mode ISDN/STN visiophone terminal according to the invention;
FIG. 2 shows the routing of audio and video data flows in the terminal according to the invention during the recording of a message inviting a calling party to leave a message on the answering/recording system;
FIG. 3 shows the routing of audio and video data flows during the transmission of the invitation message following a call via the ISDN;
FIG. 4 shows the routing of audio and video data flows during the transmission of the invitation message following a call via the STN;
FIG. 5 shows the routing of audio and video data flows during the recording of a message sent from a remote ISDN terminal to the answering/recording system of the terminal according to the invention;
FIG. 6 shows the routing of audio and video data flows during the recording of a message sent from a remote STN terminal to the answering/recording system of the terminal according to the invention;
FIG. 7 shows the routing of audio and video data flows during the reading of messages recorded on the answering/recording system of the terminal according to the invention.
The invention makes use of functions implemented in a dual-mode visiophone terminal that provides an entirely static answering/recording function that can record voice and images sent from the calling terminal.
FIG. 1 shows a block diagram of a dual-mode ISDN/STN visiophone ter
REFERENCES:
patent: 5490247 (1996-02-01), Tung et al.
patent: 5511003 (1996-04-01), Agarwal
patent: 5537141 (1996-07-01), Harper et al.
patent: 5644355 (1997-07-01), Koz
"Thomson-CSF"
Ngo Ricky
Safourek Benedict V.
Tripoli Joseph S.
Wein Frederick A.
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