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Description  |
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The present invention relates to a multi-location television conference
system to which a plurality of conference terminals are connected using a
switching means, so that conferences can be conducted between the
conference terminals.
FIG. 1 is a block diagram showing a conventional multi-location television
conference system such as the one disclosed in, for example, Japanese
Patent Kokai Publication No. H1-265767. The illustrated conference system
comprises a plurality of conference terminals CT participating in
multi-location television conferences, a ring network RN to which the
conference terminals CT are connected, and a conference device CD
connected to the ring network RN to hold the conferences.
The television conference is held using a multiple-address, simultaneous
communication channel and an individual communication channel of a
time-division multiplex channel as a communication path RN of ring network
configuration. That is, in a television conference terminal CT, video and
audio conference data are input by means of a video camera and a
microphone, and are then placed by means of a transmitter onto the
individual communication channel of the ring network RN for transmission
to the conference device CD.
The conference device CD uses its receiver to receive conference data from
the respective conference terminals CT via the individual communication
channels of the ring network RN and synthesizes them at the conference
data synthesizer. It then places the synthetic conference data through its
transmitter onto the multiple-address communication channel of the ring
network RN and sends it to all the conference terminals CT.
Each of the conference terminals CT, using its receiver, receives the
conference data on the multiple-address channel of the ring network RN,
and outputs them by means of an image display, such as a television
monitor, and a loudspeaker.
When a switching device is used in place of the ring network RN, it is
possible to effect multi-location conferences in a similar manner by
connecting between the conference device CD and the switching device with
a plurality of lines, thereby providing one-to-one connection between each
conference terminal CT and the conference device CD via the switching
device.
Because the conventional multi-location television conference systems are
configured as described above, they are associated with a number of
problems. First, their applicability is limited when they make use of a
ring network RN within a specific corporation or an establishment, and
they cannot, for example, be applied to multi-location conferences between
widely separated locations, such as between distant cities. In addition,
in a conventional multi-location television conference system implemented
by means of an integrated services digital network (hereinafter
abbreviated "ISDN"), the number of lines subscribed to connect the
conference device CD with the ISDN must not be less than the maximum
number of terminals participating in the conference. When multi-location
conferences are held between a small number of conference terminals CT,
there will be a considerable number of lines which are subscribed but are
not actually used. Thus, the ratio of utility of the lines is low.
Moreover, when each conference can be held with a selected one of a
plurality of line speeds, e.g., H.sub.0 (384 kbps) and 2 B (2.times.64
kbps), the utility of the conference devices may be low if no particular
consideration is given since each conference device cannot communicate
with the conference terminals at different line speeds simultaneously.
That is, each conference device CD cannot communicate with the conference
terminals at different line speeds simultaneously: when it communicates
with a particular terminal at one of the line speeds (e.g., 2 B), it
cannot simultaneously communicate with another conference terminal CT at
another line speed (e.g., H.sub.0). As a result, each conference device CD
cannot hold conferences at different line speeds simultaneously: when it
holds a conference at one of the line speeds, it cannot simultaneously
hold another conference at another line speed. When for instance all the
conference devices CD have been assigned to conferences at a certain line
speed, no further conference cannot be held at a different line speed even
if there are adequate vacant lines with which the conference terminals
which are to participate in the contemplated conference can be connected
to any of the conference devices CD.
SUMMARY OF THE INVENTION
An object of the present invention is to make it possible to automatically
control starting and ending of such multi-location conferences in
accordance with previously collected reserved conference information.
Another object of the present invention is to make it possible to hold a
plurality of multi-location conferences simultaneously.
Another object of the invention is to improve the utility of the conference
devices and the communication lines connecting the conference devices with
the conference terminals.
A multi-location conference system in accordance with one aspect of the
invention comprises:
a plurality of conference terminals performing input and output of
conference data consisting of video and audio signals; and
a conference device which is connected to said plurality of conference
terminals and which holds conferences between said plurality of conference
terminals by synthetic processing of conference data sent to it;
characterized in that:
said conference device is provided with a conference table storing
information for the conference terminals participating in the conferences
being held; and
said system further comprises a reservation center for registering
conference terminal information in said conference table and deleting the
conference terminal information from the conference table at times
designated in accordance with reserved conference information collected in
advance for the respective conferences, thereby controlling automatically
starting and ending of each of the conferences.
With the above configuration, the conference table manages the conference
terminal information, and thus arranges for the holding of multi-location
conferences in accordance with the reserved conference information
previously registered in the reservation center, with the result that the
starting and ending of these conferences are controlled automatically, and
a plurality of multi-location conferences can be held simultaneously.
There may be further provided a reservation terminal connected to the
reservation center via a communication line, and the reserved conference
information may comprise a reservation decision information requisite for
making the decision as to whether to accept or reject the reservation, and
reservation detail information, and the reservation terminal sends the
reservation decision information via a communication line to said
reservation center, the reservation center, responsive to the reservation
decision information, makes decision as to whether to accept or reject the
reservation at said reservation center and sends the result of decision to
said reservation terminal, and the reservation terminal sends, if the
result of the decision is to accept the reservation, the reservation
detail information to said reservation center, thereby to achieve the
registration of the reserved conference information in the reservation
center.
With the above configuration, the reservation detail information is sent
only after the reservation is accepted. As a result, the overall amount of
information that is exchanged for the reservation is reduced, allowing the
use of low-speed components, e.g., a low-speed modem.
A multi-location television conference system according to another aspect
of the invention comprises:
a plurality of first television conference terminals that can be connected
to a communication network with a first line speed;
a plurality of second television conference terminals that can be connected
to said communications network with a second line speed;
a plurality of conference devices which are connected by a plurality of
lines to said communication network, and which are capable of
simultaneously holding multi-location conference at a selected one of said
first and second line speeds; and
an operational management device to which said conference devices are
connected, which determines, at the time of convening a multi-location
conference, the conference device which is to hold the conference by
searching for the conference device which can hold the conference with the
line speed with which the television conference terminals participating in
the conference can be connected, and the line speed and the number of
vacant lines of each of the conference devices, in an order different
depending on the specific line speed, and which controls starting and
ending of the conference.
A multi-location television conference system according a further aspect of
the invention comprises:
a plurality of first television conference terminals that can be connected
to a communication network with a first line speed;
a plurality of second television conference terminals that can be connected
to said communications network at a second line speed;
a plurality of conference devices which are connected by a plurality of
lines to said communication network, and which are capable of
simultaneously holding multi-location conferences with a selected one of
said first and second line speeds; and
an operational management device to which said conference devices are
connected, which has a reservation file capable of storing reserved
conference information including starting time and ending time of each of
the multi-location conferences and a clock by which it is possible to
indicate the current time, which reserves a conference device, and which
controls starting and ending the conference;
wherein, at the time of reserving a multi-location conference, said
operational management device determines, in accordance the number of the
conference terminals which are to participate in the conference, as well
as the line speed with which the reservation has been made for each
conference device, and the number of vacant lines of each conference
device, the conference device which is to be reserved for the conference
by searching for the conference device which can hold the conference with
the line speed with which the television conference terminals which are to
participate in the conference can be connected, wherein said search is
made in an order different dependent on the specific line speed.
With the above configuration, it is possible to realize a conference device
with which the vacant lines of the conference system can be efficiently
utilized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the configuration of a conventional
multi-location conference system.
FIG. 2 is a block diagram showing the configuration of a multi-location
conference system in accordance with an embodiment of the invention.
FIG. 3 is a block diagram showing the configuration of a conference device
used in the embodiment of FIG. 2.
FIG. 3A and FIG. 3B are diagrams showing an example of the conference data
synthesizer in FIG. 3.
FIG. 4 is a block diagram showing the configuration of an example of a
conference terminal used in the embodiment of FIG. 2.
FIG. 5 is a block diagram showing the configuration of an example of a
reservation center used in the embodiment of FIG. 2.
FIG. 6 is a block diagram showing the configuration of an example of a
conference table used in the embodiment of FIG. 2.
FIG. 7 is a block diagram showing the configuration of an example of a
reservation file at the reservation center used in the embodiment of FIG.
2.
FIG. 8 is a flow chart for explaining the operation of the embodiment of
FIG. 2.
FIG. 9 is a block diagram showing the configuration of a multi-location
conference system of another embodiment of the invention.
FIG. 10 is a block diagram showing the configuration of an example of a
reservation terminal used in the embodiment of FIG. 9.
FIG. 11 is a block diagram showing the configuration of an example of a
reservation file at the reservation center used in the embodiment of FIG.
9.
FIG. 12 is a processing sequence for explaining the registration of the
reserved conference information in the embodiment of FIG. 9.
FIG. 13A to FIG. 13C are diagrams showing various pieces of information
sent and received between the reservation center and the reservation
terminal in the embodiment of FIG. 9.
FIG. 14 is a schematic diagram showing a multi-location television
conference system of another embodiment of the invention.
FIG. 15 is an explanatory drawing showing the configuration of an example
of a conference table used in the embodiment of FIG. 14.
FIG. 16 is a block diagram showing the configuration of an example of an
operational management device used in the embodiment of FIG. 14.
FIG. 17 is an explanatory drawing showing an example of the operational
table used in the embodiment of FIG. 14.
FIG. 18 is a flow chart showing the processing procedures for checking
whether it is possible to convene a conference or not.
FIG. 19 is a timing diagram showing the basic call control sequences in the
embodiment of FIG. 14.
FIG. 20 is a block diagram showing the configuration of an example of an
operational management device used in another embodiment of FIG. 14.
FIG. 21 is an explanatory drawing showing an example of a reservation file
in the operational management device of FIG. 20.
FIG. 22 is a flow chart showing the processing procedures for checking
whether it is possible to make a conference reservation or not.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
FIG. 2 is a block diagram showing the configuration of a multi-location
conference system in accordance with a first embodiment of the invention.
The illustrated conference system comprises a conference device 1,
television conference terminals 3 connected to the conference device 1 via
a switching device, such as an ISDN 4, and a reservation center 5
connected to the conference device 1.
The functions of the conference device 1 and the conference terminals 3 are
basically identical to those of the conference device CD and the
conference terminals CT in FIG. 1. The switching device 4 is used in place
of the ring network RN in FIG. 1, and provides corresponding functions.
One of the terminals 3 is designated a master terminal 3m, and other
terminals are designated subordinate terminals 3s, one of which is
designated a representative terminal 3rs. In the illustrated embodiment,
it is assumed that the terminals 3 are operated by the personnel of
various departments of a corporation at distant geographical locations. It
is convenient if they are situated at or near the offices of the
respective departments, and the master terminal 3m is disposed, e.g., at
or near the office of the president of the corporation. The reservation
center 5 is manipulated by the personnel of the department of the
corporation in charge of the management of the conference system, and may
be disposed at or near the office of such department. The conference
device 1 on the other hand need not be manipulated during conference or
reservation of the conference, and as it requires a considerable space for
installment, it may conveniently be situated at a location relatively
remote from the offices, e.g., in the exchanger room of the office
building. In the illustrated embodiment, the conference device 1 and the
reservation center 5 are assumed to be situated in the same office
building or same premise, and the switching device 4 is not used for
interconnecting the conference device 1 and the reservation center 5.
The configuration of the conference device 1 is shown in FIG. 3. As
illustrated, the conference device 1 comprises transceivers 11 which are
provided for each of the lines connected to the switching device 4. The
transceivers 11 are connected via the switching device 4 to the conference
terminals 3, and temporarily store data sent from the connected conference
terminals 3. Digital-to-analog (D/A) converters 12 and analog-to-digital
(A/D) converters 14 are connected to the respective transceivers 11. The
D/A converters 12 convert the conference data received and stored at the
corresponding transceiver 11, into an analog signal.
A conference data synthesizer 16 performs synthetic processing on the
conference data received from the D/A converters 12. The synthetic
processing includes selective mixing (superimposition) of audio signals
and selection of video signals. That is, for each intended terminal
(master terminal or a subordinate terminal) participating in a conference,
the audio data sent from all the terminals participating in the same
conference except the terminal in question are mixed and sent to the
terminal in question. For the master terminal in a conference, the video
signals from the representative terminal in the same conference is
selected and sent to the master terminal. For each of the subordinate
terminals in a conference, the video signals from the master terminal is
normally selected and sent to each of the subordinate terminals in the
same conference. When one of the subordinate terminals is making a speech,
the video signals from this subordinate terminal may be selected and sent
to other subordinate terminals and to the master terminal.
The conference data synthesizer 16 performs the synthetic processing by
referring to conference terminal information stored in a conference table
17. This means that the conference table 17 stores the information
determining the specific manner of synthesis, i.e., selection of the video
signals and selective mixing of the audio signals. The contents of the
conference table 17 can be altered by manipulation of an input means (not
shown) at the master terminal 3m. That is, the selection of the video
signals and the selective mixing of the audio signals can be altered by
manipulation of the input means at the master terminal 3m.
The conference data synthesizer 16 can perform synthetic processing for a
plurality of conferences concurrently. FIG. 3A and FIG. 3B are schematic
illustrations of an example of the conference data synthesizer 16. FIG. 3A
shows the part of the synthesizer 16 relating to the audio signals, and
FIG. 3B shows the part of the synthesizer 16 relating to the video
signals. In FIG. 3A and FIG. 3B, it is assumed two conferences are held
simultaneously, and conference denoted by 3m-1, 3rs-1 and 3s-1 are
participating in one of the conferences, and conference terminals denoted
by 3m-2, 3rs-1 and 3s are participating in another conference. The
horizontal lines are connected to the D/A converters 12 for the respective
terminals 3m-1, 3rs-1, 3s-1, 3m-2, 3rs-2 and 3s-2, and the vertical lines
are connected to the A/D converters for the respective terminals 3m-1,
3sr-1, 3s-1, 3m-2, 3rs-1 and 3s-2. In FIG. 3A and FIG. 3B, the marks "x"
at the intersections between horizontal and vertical lines indicate that
the intersecting lines are connected with each other. In FIG. 3A, the
signal appearing on a vertical line results from mixing the signals from
the horizontal lines with which the vertical line is connected. In FIG.
3B, the signal appearing on a vertical line results from selection of the
signal from the horizontal line with which the vertical line is connected.
The A/D converters 14 convert the analog signals that have been produced
from the synthesizer 16, and output the digital signals. The transceivers
3 receive the digital data from the respective A/D converters 14 and send
them to the conference terminals to which they are connected.
The conference data synthesizer 16 is connected to the conference table 17.
The conference table 17 is configured as shown in FIG. 6, and stores
conference information 50 on each of the conferences being held by the
conference device. Conference information 50 for each conference consists
of a conference status field 51 which indicates whether there is a
conference in progress ("1") or not ("0"); a conference number field 52,
consisting, for example, of a 4-bit numeral (no duplication permitted); a
master terminal field 53 indicating the conference terminal 3 acting as
the conference host; a representative terminal field 54 indicating one of
the subordinate terminals which acts as the representative; a subordinate
terminal number field 55 indicating the number of conference terminals 3
other than the conference host (master terminal); and subordinate terminal
fields 56-1 to 56-M identifying the respective subordinate terminals 3s
participating in the conference. The information identifying each
subordinate terminal may consist of the telephone number.
The configuration of each of the conference terminals 3 is shown in FIG. 4.
As illustrated, it comprises a conference data input means 31, such as,
for example, a microphone, video camera or the like, for inputting audio
and video data, and a conference data output means 32, such as, for
example, a loudspeaker, television monitor or the like, for outputting
audio and video data (the synthetic conference data resulting from the
synthetic processing carried out at the conference device 1. The
conference terminal 3 further includes a terminal transceiver 33 with the
functions of receiving and temporarily storing the data from the switching
device 4 and of sending the temporarily stored data, an A/D converter 34
for converting the conference data (analog signals) input from the
conference data input means 31 into digital signals capable of being sent,
and a D/A converter 35 for converting the synthetic conference data
(digital signals) received by the terminal transceiver 33 into analog
signals.
The reservation center 5 performs automatic control of starting and ending
of multi-location conferences carried out by the conference device 1. As
illustrated in FIG. 5, the reservation center 5 comprises an input means
41, such as, for example, a keyboard or the like, for the inputting of
reserved conference information, a display means 42, such as, for example,
a television monitor or the like, by which the operator is informed of the
reserved conference information and of the operational status of
multi-location conferences being held by the conference device 1 to which
it is associated. A clock 43 provides information on the time, i.e., the
year, month, day, hour, minute and second. A conference reservation
control means 44 provides for new registration, modification and deletion
of the reserved conference information, and indicates, when the time comes
for the starting or ending of the reserved conference information, the
starting or ending of the respective conferences. A reservation file 45 is
in the form of a storage medium such as, for example, a hard disk, which
stores the reserved conference information input as above described.
The reservation file 45 is composed of a plurality of blocks of reserved
conference information 60 as shown in FIG. 7, and each block of the
reserved conference information 60 is comprised of a field for the
reserved conference status 61, which is at "0" if the conference has not
been started, at "1" if it is in progress and at "2" if it has ended. The
reservation file 45 also includes a field 62 for the reserved start time
indicating the time a reserved conference starts, a field 63 for the
reserved end time indicating the time a reserved conference ends, a field
64A for the reserved conference number consisting, for example, of four
bits (no duplication permitted), a field 65 for the reserved master
terminal which acts as the host of the reserved conference, a field 66 for
the reserved representative terminal 66 which is one of the reserved
subordinate terminals designated to act as the representative, a field 67
indicating the number of reserved subordinate terminals, and fields 68-1
to 68-M for identifying the respective reserved subordinate terminals
which participate in the reserved conference.
The operation of the conference system will now be described with reference
to FIG. 8. At step ST1, the conference reservation control means 44 first
reads information on the year, month, date, hour, minute and second from
the clock 43, and then, at (at step ST2) reads sequentially, in descending
order (from the head to the tail), from the reservation file 45, the
reserved conference information for which the reserved conference status
field 61 contains a value other than "2". Then (step ST3), the reserved
start time 62 in the field for the reserved conference information 60 of
which the reserved conference status field 61 contains "0" is compared
with the current time information read from the clock 43 in step ST1.
When the current time and the reserved start time are found to match, the
contents of the field for the reserved conference information 60 in the
reservation file 45 of the reservation center 5 are transferred (copied)
to the area for the conference terminal information 50 in the conference
table 17 of the conference device 1 of which the conference status field
51 contains "0" (step ST4), and the reserved conference status field 61 of
that reserved conference information 60 is set to "1" (step ST5).
The transferring operation above described consists of transferring and
storing the content of the reserved conference number 64A to the field 52
for the conference number in the conference information 50, the content of
the reserved master terminal 65 to the field 53 for the master terminal,
the content of the reserved representative terminal 66 to the field 54 for
the representative terminal, the content of the number of reserved the
subordinate terminals 67 to the field 55 for the number of the subordinate
terminals, and the contents of the reserved subordinate terminals 68-1 to
68-M to the fields 56-1 to 56-M for the subordinate terminals, thereby
enabling the conference information synthesizer 16 to hold a plurality of
conferences simultaneously in accordance with the conference table 17.
Next, a comparison is made (step ST6) between, on one hand, the reserved
end time 63 of the reserved conference information 60 of which the
reserved conference status 61 is "1" and, on the other, the current time
information read from the clock 43 in step ST1, and if the current time
and the reserved end time are found to match, the corresponding conference
information 50 is deleted from the conference table 17, i.e., the
conference status 51 is reset to "0" (Step ST7), the reserved conference
status 61 in the reserved conference information 60 described above is set
to "2" (step ST8). The above operations are performed throughout the
entire file (step ST9).
In the embodiment above described, the explanation was made on the
assumption that the switching device 4 such as an ISDN was used as the
switching means connecting the conference terminals 3 and the conference
device 1 and transferring data between them. But similar results may be
achieved by the use of a ring network.
As has been above described, in accordance with the first embodiment, it is
possible to conduct a plurality of multi-location conferences
simultaneously and to effect automatic control of the starting and ending
of each of the conferences, by providing in a conference device a
conference table that manages conference information and execution and
management of multi-location television conferences are made in accordance
with reserved conference information registered in the reservation center.
Second Embodiment
A second embodiment of the invention will now be described with reference
to FIG. 9, in which parts that are identical with or corresponding to
those of the multi-location conference system of FIG. 2 to FIG. 7 are
identified with the same reference numerals, and their description is
omitted.
As illustrated in FIG. 9, the reservation center 5 of this embodiment is
connected via a communication line such as a telephone line 7 to
reservation terminals 8. For connection of the reservation center 5 with
the telephone line 7, modems 6 are inserted. The reservation terminals 8
are used for sending reserved conference information from remote locations
to the reservation center 5. The reservation terminals 8 may be in the
same premises or same office building as the conference terminals 3, and
may be disposed adjacent to the conference terminals 3.
The configuration of each reservation terminal 8 is shown in FIG. 10. As
illustrated, it comprises a reservation terminal input means 71 such as a
keyboard or the like for inputting the reserved conference information 60,
a reservation terminal display means 72 such as a television monitor or
the like for displaying information concerning operation for registration
in the reservation center 5, and a reservation terminal control means 73
for the new registration, modification or deletion of the reserved
conference information 60.
The configuration of the reservation file 45 at the reservation center 5 of
this embodiment is shown in FIG. 11, in which parts that are identical
with or corresponding to those parts in the reservation file 45 of the
first embodiment of FIG. 2 to FIG. 8 are identified with the same
reference numerals, and their description is omitted. As illustrated in
FIG. 11, the reservation file 45 includes a field 64B for indicating the
conference name consisting, for example, of 20 characters in "kanji"
(Chinese characters) and/or alphanumeric code, a field 65a for identifying
the terminal, a field 65b for identifying the participating department at
the master terminal, consisting of 6 alphanumeric characters, a field 65c
for identifying the person in charge at the master terminal, consisting of
10 characters in "kanji" and/or alphanumeric code, a field 65d for
indicating the telephone number of the master terminal, consisting of 20
numeric characters, a field 65e for the indicating the number of
participating persons at the master terminal, consisting of 2 numeric
characters, and fields 68-1 to 68-M for the respective subordinate
terminals.
Each of the fields 68-1 to 68-N comprises a field 68a for identifying the
terminal, a filed 68b for identifying the participating department at the
subordinate terminal consisting of 6 alphanumeric characters, a field 68c
for identifying the person in charge at the subordinate terminal,
consisting of 10 characters in "kanji" and/or alphanumeric code, a field
68d for indicating the telephone number of the subordinate terminal,
consisting of 20 numeric characters, and a field 68e for indicating the
number of participating persons at the subordinate terminal, consisting of
2 numeric characters.
The procedure for the registration of a reserved conference information at
the reservation center, is shown in FIG. 12.
The operations of the system other than the registration procedure are
similar to those of the first embodiment, and their description is
omitted. The operations for the registration of this embodiment differ
from those of the First Embodiment in that the reservation information is
divided into reservation decision information and reservation detail
information, and the reservation information is first sent from one of the
reservation terminals 8 to the reservation center 5, a decision is made at
the reservation center 5 as to whether to accept or reject the
reservation, the result of the decision is sent from the reservation
center 5 to the reservation terminal 8, and, if the result of the decision
indicates that the reservation is accepted, the reservation detail
information is then sent from the reservation terminal 8 to the
reservation center 5.
For example, the reservation decision information comprise information in
the fields 62, 63, 65a, 66, 67 and 68a in FIG. 11, and the reservation
detail information comprise the information in the remaining fields in
FIG. 11.
The above-outlined operations are next described in further detail.
Once a one-to-one connection has been established between the reservation
center 5 and one of the reservation terminals 8, via the modem 6 and the
telephone line 7 (201), items of reservation conference information 60 are
input using the reservation terminal input means 71 (202).
At this time, reservation center 5 is in the standby state, ready to
receive a command from the reservation terminal 8.
Once all the items have been input to it, the reservation terminal 8 sends
information of a transmission pattern shown in FIG. 13A to the reservation
center 5, for registering the reservation (203). On the basis of the
reservation decision information of the transmission pattern that has been
received (see FIG. 13A), the reservation center 5 makes a decision by
referring to the reservation file 45 as to the status of the conference
terminals 3 and the conference devices 1, and if the reservation can be
accepted, a reservation number is assigned and written in the reserved
conference number field 64A and a reservation key code is created (204),
and information of a transmission pattern shown in FIG. 13B is then
returned to the reservation terminal 8 (205).
When it receives this return pattern of FIG. 13B, the reservation terminal
8 notifies the operator by display (206) appearing on the reservation
terminal display means 72 as to whether the reservation request has been
accepted or not, and if the reservation has been accepted, sends to the
reservation center 5 the reservation detail information previously input,
along with the key code received in a transmission pattern shown in FIG.
13C (207). When the reservation detail information is received at the
reservation center 5 the information is registered as the reserved
conference information 60, in the reservation file 45 (208). When this
registration is completed, the communication line between reservation
terminal 8 and reservation center 5 is disconnected (209).
As an example, the time required for sending the reservation decision
information is about 1 to 2 seconds, and the time require for sending the
reservation detail information is on the order of 10 seconds.
In the Second Embodiment above described, the telephone line 7 was used as
a communication line connecting the reservation center 5 and the
reservation terminals 8, a similar effect can be achieved by the use of a
dedicated line or private communication line.
In the Second Embodiment above described, a plurality of reservation
terminals 8 are provided. But, there may be only one reservation terminal
8.
In accordance with the Second Embodiment, when it is desired that the
registration of the reserved conference information at the reservation
center be carried out at reservation terminals connected via communication
lines, the reservation decision information required for the decision as
to whether to accept or reject the reservation is sent first, and a
decision as to acceptance or rejection of the reservation made, and the
reservation detail information is thereafter sent from the reservation
terminal to the reservation center only after the reservation is accepted.
An advantage is that the decision can be made in shorter times, and
transmission equipment, such as modems, with lower transmission speed can
be used.
Third Embodiment
A third embodiment of the invention will now be described with reference to
FIG. 14. As in the First and Second Embodiments, an ISDN 104 is used as
the communication line. The ISDN 104 may have D channels, B channels and
H.sub.0 channels, and permits transfer of data at a selected one of line
speeds of 2B and H.sub.0. A plurality of conference devices 105 are
connected to the ISDN 104 by a plurality of lines. Each of the conference
devices 105 can hold multi-location conferences with a line speed of
either 2B or H.sub.0. Each conference device 105 however cannot
communicate with the conference terminals at different line speeds
simultaneously: when it communicates with one of the line speeds (e.g.,
2B), it cannot simultaneously communicate with another conference terminal
at a different line speed (e.g., H.sub.0). As a result, the conference
must be conducted at a line speed at which the conference terminal having
the lowest line speed capability can communicate with. Another consequence
is that each conference device 105 cannot hold conferences at different
line speeds simultaneously: when it holds a conference at one of the line
speeds, it cannot simultaneously hold another conference at a different
line speed. When for instance all the conference devices 105 have been
assigned to conferences at a certain line speed, another conference cannot
be held at a different line speed even if there are adequate vacant lines
with which the conference terminals which are to participate in the
contemplated conference can be connected to any of the conference device
105. The present embodiment has been conceived to overcome this problem.
It relates to the manner of assignment of conference devices which
maximizes the utility of the conference devices.
A plurality of television conference terminals 106 and 107 are connected to
the ISDN 104. The television conference terminals 106 can be connected to
the ISDN 104 designating a line speed of either 2B or H.sub.0, while the
television conference terminals 107 can be connected to the ISDN 104 only
at a line speed of 2B. An operational management device 108 is connected
to the conference devices 105 and controls starting and ending of
multi-location conferences.
The configuration of the conference device 105 may be similar to the
conference device 1 shown in FIG. 3. But the transceiver 11 is capable of
specifying the line speed as either 2B or H.sub.0.
The conference table 115, shown in FIG. 15, used in the conference device
in this embodiment is similar to the conference table 17 of FIG. 3, but is
also provided with a field 129 for indicating the line speed, in addition
to the blocks of conference information 120. Each block of conference
information 120 is shown on the | | |
