JP2594089B2 - Two-way video communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a video conference using a coaxial CATV
It relates to videophones, video service systems, and the like.

(Prior Art) Conventionally, this type of bidirectional video communication system mainly communicates between fixed facilities using a dedicated line.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional two-way video communication system, moving picture video telephones and moving picture video conferences are mainly one-to-one using dedicated lines.
In order to communicate between arbitrary points, a large-scale system using a video channel, for example, a video switching device capable of exchanging a wideband signal with a wideband communication path such as 6 MHz or 32 bits / second (BPS), etc., is used. There was a necessary problem.

The present invention uses an empty channel of a television co-listening system such as CATV, and uses this for multi-channel access (hereinafter referred to as MCA).
It is an object of the present invention to provide a two-way video communication system that performs two-way video and audio communication by applying the method.

(Means for Solving the Problems) In order to achieve the above object, the present invention determines a line use state of a called side when receiving an access request from a calling side through a television co-listening system such as CATV. When the line is not in use, the request from the caller is permitted, and two of the available TV channels in the TV co-listening system are used for voice, fax, and multi-channel access by the multi-channel access (MCA) system. Reserved for data line,
Further, while securing a plurality of channels among the empty TV channels for the videophone transmission path, the information of the empty TV channels is searched according to the request from the calling side, and the calling side and the called side are searched. On the other hand, the MCA system instructs the reserved vacant TV channel by the MCA system, so that a center device for setting the used channel of the calling side and the called side is provided, and the calling side and the called side transmit the image of the television camera. In this way, the video signals are displayed on the receivers and the telephone conversation is possible.

(Operation) Therefore, according to the present invention, video communication between subscribers and between the center and the subscribers is enabled by adding the terminal device of the above-described two-way video communication system to the television common listening network. It has the effect of.

(Embodiment) FIG. 1 and FIG. 2 show the configuration of an embodiment of the present invention. FIG. 1 is a functional configuration diagram of a center facility of an interactive video communication system, and FIG. 2 is a functional configuration diagram of a subscriber facility of the above system.

In FIG. 1, 1 is a center device, 11 is a television antenna, 12 is a television co-listening device, 13 is a TV studio, 14 is an independent TV program device, 15 is an MCA communication center device, 16 is a keyboard, and dials and function buttons. It has a telephone handset. Reference numeral 17 denotes a controller of a two-way video communication system (hereinafter, referred to as a video telephone controller), reference numeral 18 denotes a memory for storing the channel number, call number, usage time, and the like of the video telephone controller 17; reference numeral 19 denotes an optical fiber or a coaxial line. Head-end device for coupling with the transmission line 20 of
TV telephone device, 22 to 26 are main bodies of the video telephone device, 27 is a receiver (TV receiver), A is a speaker attached to the TV receiver 27, 28 is a TV camera, and B is a microphone attached to the TV camera. , 29 is a video phone controller, and 30 is a channel checker, which forms a center device and a video phone device (center equipment) of the MCA communication system.

FIG. 2 shows a subscriber unit of the video telephone. In FIG. 2, reference numeral 20 denotes a transmission line, which connects the subscriber devices from the center device 1 in series. 21 is a signal coupler, 3 is a videophone device of the subscriber's equipment, 31 is a filter for separating the image transmission and reception channels, 32 is a switch connected to either side of the filter 31, 33 is a TV signal receiver, 34 is a frequency synthesizer for switching channels, 35 is a TV signal transmitter, 36 is
TV receiver, A is a speaker attached to TV receiver 36,
Reference numeral 37 denotes a TV camera, B denotes a microphone attached to the TV camera 37, and 38 denotes a video phone controller, which form the majority of the video phone device. 39 is a filter for sharing the communication device of the MCA system with that for CATV reception, 40 is an MCA communication device, 41 is a keyboard including dials and function buttons for accessing the MCA communication system and the video telephone system, and C is a dial or the like. An indicator, D is a dial and function button, and E is a telephone handset. 42 is a television receiver for CATV.

FIG. 3 shows an example of the channel arrangement of this embodiment. In FIG. 3, the television channel in G ₁ are 50MHz band, G
₂ is a 150 MHz band television channel, and G ₃ is a 400 MHz band UHF television channel. In addition, TV indicates a television broadcast, unmarked indicates an empty channel, MCA indicates a channel for an MCA communication system, and TVT indicates a channel for a videophone. MCA and TVT above
Are not specially allocated, but use the empty channels of commercial television only in the television listening network.

The MCA communication system uses a TV channel of 6 MHz as a narrow-band communication path, and 120 channels in a 50 kHz bandwidth.
However, it is divided into n groups, and one group is divided into m channels, and is used for telephone communication, facsimile communication, and security communication as an MCA system.

TVT has a 6 MHz interval similarly to commercial television broadcasting, and is considered economical so that a general commercial color television receiver and television camera can be used.

FIG. 4 shows a flow of connection of a call image in the above embodiment.

Next, the operation of the above embodiment will be described. In FIG. 1, as a CATV, a plurality of commercial televisions are received by a TV consonant device 12 via a television antenna 11, amplified in power, and transmitted to a television consonant network through a head end 19. In addition, independent programs and video signals from the TV studio 13
The data is transmitted to the TV shared network through the TV program device 14 and the head end 19.

 Next, a case of making a videophone call will be described.

(1) When making a videophone call from the center to a dwelling unit 1 subscriber, the operator of the center device 1 must dial the keyboard 16 (D).
Dial the dwelling unit 1 subscriber number. This dial indicates a videophone. For example, * 3 is the number of one dwelling unit subscriber
When 0136, MCA center apparatus 15 sends the called party number 0136 by accessing the TV telephone controller 17 (Fig. 4 S _1). The video phone controller 17 accesses the memory 18 to check whether the TVT channel memory and 0136 are in a call,
Permit the request of the calling center that videophone, further selects an empty TVT channel pairs, the calling center to the group G ₂ a TVTch2 of FIG. 3 group G ₃ to 0136 of the called
Of TVTch2. During this time, the MCA center apparatus 15 calls 0136 of the dwelling unit 1, and the communication channel (S channel)
Keep let switched on (Fig. 4 S _2, S ₃₎ MCA center device 15
It gives an instruction to use the TVTch2 of G ₂ to 0136 is. The data coupler 21 of 0,136 dwelling units 1 by MCA system, TV telephone controller 38 to the TVT channel number via the MCA communication device 40 from the filter 39, transmitting the TVTch2 of G ₂ (FIG. 4 S _4). The TV phone controller 38 is a TV signal receiver 33 and a TV
The used channel data is supplied to the frequency synthesizer 34 of the signal transmitter 35, which generates the transmission frequency from the receiving station, to operate the frequency synthesizer 34, and the ringing bell is sounded. This call may be made at a call stage before issuing a TVT channel command. Here, if the called party answers, the center and the dwelling unit 1
Communication TV telephone between 0136 of starts (Fig. 4 S _5). The above is a method that uses both the MCA system telephone and the TVT video system, but calls are made using the speaker of the TV receiver, hands-free communication using the microphone of the TV camera, the speaker of the TV receiver and the handset of the MCA system. Various forms such as using a transmitter or a separately provided hand microphone (not shown) can be employed. Ending can be done on either side.

(2) When making a videophone call between dwelling unit 1 and dwelling unit 2, the caller of dwelling unit 1 dials the TVT number of the called party using keyboard 41. For example, the dial number is * 3-1298. The dialed number is sent from the 0136 dwelling units 1 to MCA center device 15 of the center device 1 (Fig. 4 S _6), the data is sent to the TV telephone controller 17 of the center apparatus 1, the TV telephone controller 17 Check whether there is room in the busy and TVT channels of the 1298 (Fig. 4 S _7). If the above 1298 is not busy, the request of the dwelling unit 1 to make a videophone call is permitted, and if there is an available channel, the channel number is set to TVTch4.
To the, the TVTch4 of G ₃ to 1298 dwelling units 2 to dwelling units 1 G ₂ TV and
It emits a signal indicating TCH4 (Figure 4 S _8). During this time MC
The A-center device 15 sets a call channel (Sch
The p), advance let switch instructs the call channel (Schp ') to 1298 dwelling units 2 (FIG. 4 S _9, S _10), and instructs the transmission from the G ₂ TVTch4 to 1298 dwelling units 2 continued (Fig. 4 S
₁₁ ). 1298 of dwelling unit 2 responds to 1298 by G ₂ TV
Sends the video of the television camera 37 in TCH4, performs receiving of G ₃ TVTch4 the TV receiver 36, while the dwelling unit 1 side performs receiving by Sozo and G ₂ TVTch4 by G ₃ TVTch4. For the voice, some of the communication methods described in the above (1) are used.

(3) Videophone call end When the call is ended, the call is ended from either the dwelling unit 1 side or the dwelling unit 2 side by operating the on-hook of the handset E of the keyboard 41 or the operation of the end call button. is notified to the first TV telephone controller 17 (Fig. 4 S _12), again the clearing signal transmitted from the center apparatus 1 is performed (Fig. 4
S _13, S _14).

It should be noted that a function button can be provided on the keyboard to switch between a hands-free call using the microphone of the TV camera and the speaker of the TV receiver, a handset call sharing the MCA system, and a hand-free call using the hand microphone and the speaker of the TV receiver. And allow the user to make free choices.

Further, although the transmission signal of the videophone has been described as the FDM system, the same function is obtained in the case of the TDM system.

In addition, use coaxial lines or optical fiber lines for transmission lines, use CATV for downstream and separate lines for upstream, use a separate line to arrange channels freely, ignoring commercial TV, and use double lines. Any of the above can be performed by physically dividing the band.

(Effects of the Invention) As is apparent from the above embodiment, the present invention enables two-way communication of video and audio by using an idle channel of the co-listening system. This has the effect that it can be realized in Further, the center device determines the use status of the line, and when the center device determines that the line can be used, permits transmission of a communication request to each terminal, and further searches for an empty channel used for transmitting a video signal. However, by allocating the available free channels to the calling side and the called side, there is an effect that the free channels can be appropriately and efficiently allocated.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a video telephone (TVT) using a CATV co-hearing network according to an embodiment of the present invention. FIG. 2 is a functional block diagram of a TVT subscriber according to an embodiment of the present invention.
FIG. 4 is a channel arrangement diagram showing an embodiment of using channels, and FIG. 4 is a flowchart showing a connection procedure of a call video. 1 ... Center device, 2,3 ... TV telephone device, 11 ... TV antenna, 12 ... TV co-listening device, 13 ... TV studio, 14 ...
… Independent TV program device, 15… MCA center device, 16,41 …… Keyboard, 17,29,38 …… Video phone controller, 18 …… Memory,
19: Head end, 20: Transmission line (coaxial line or optical fiber line), 21: Coupler, 22 to 26: TV telephone unit, 27, 36 TV receiver, 28, 37 TV Camera, 30 ...
... Channel checker, 31,39 ... Filter, 32 ... Switcher, 33 ... TV signal receiver, 34 ... Frequency synthesizer,
35 TV signal transmitter, 40 MCA communication device, 42 TV receiver.

Claims (1)

(57) [Claims] When an access request is received from a calling side through a television co-listening system such as a CATV, the line use state of the called side is determined. , While securing two channels among the vacant TV channels in the TV co-listening system for voice / fax / data lines by the multi-channel access (MCA) system, A channel is reserved for a videophone transmission path, and information on the empty TV channel is searched for in accordance with a request from the calling side, and the reserved empty TV channel is retrieved for the calling side and the called side. A center device for setting channels used by the calling side and the called side by instructing the MCA system, wherein the calling side and the called side are television cameras A two-way video communication system characterized in that video signals are transmitted to each other to display video signals on a receiver and to enable communication.