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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a data communication apparatus and, more
particularly, to a data communication apparatus equipped with an oral
communication means and improved in processing a connection request coming
from another station during communication therewith using the oral
communication means.
Among data communication apparatuses such as a facsimile apparatus and a
personal computer, there exists a type which has an oral communication
means (i.e., a telephone unit) separately from the data (e.g., image
information) communication means. In this type of data communication
apparatus, it is possible to call an operator at a station to exchange
necessary information using the oral communication means in advance of
transmission of data, e.g., image information. It is, of course, also
possible to only converse by use of the oral communication means
irrespective of the necessity of transmitting data.
Recently, a new communication service (hereinafter referred to as "catch
phone" service) has been put into practice, in which when a conversation
request or a data transmission request is made from another station during
communication with one station, and the user is informed of this fact by a
sound sent from an exchange.
When the user hears calling tones of the catch phone service sent from the
exchange during oral communication, he verbally informs the person under
communication that the catch phone call has come in, to hold the
communication, and then executes a data receiving operation to receive
data from the second station.
However, conventional data communication apparatuses do not have a function
of automatically switching the telephone circuit to the previously
communicated station to re-start the conversation upon completion of the
data reception by an interrupt processing caused by the catch phone call.
Accordingly, upon completion of the data reception, the circuit is
released, and the user cannot make a conversation with the person at the
previously communicated station.
To overcome this problem, various apparatuses and systems have been
proposed which are adapted to restore the communication with the
previously communicated station after executing communication of the catch
phone service or an interrupt processing similar to it.
Japanese Patent Application Laid-Open Nos. Sho. 63-67868 and Sho. 64-86660
respectively disclose a facsimile communication system and a data
communication system in which when an interrupt instruction is given by an
operator or received from another station during transmission of image
information, the current transmission of image information is suspended to
execute the instructed interrupt processing, and after completion of the
interrupt processing the transmission of image information is resumed
automatically.
Further, Japanese Patent Application Laid-Open No. Sho. 64-78575 discloses
a facsimile apparatus which is constructed such that if transmission is
suspended due to some trouble, the stored telephone number is dialed to
transmit the image information stored in an image signal memory unit.
Further, in a facsimile apparatus disclosed in Japanese Patent Application
Laid-Open No. Hei. 2-51973, when a connection request (catch phone call)
comes in from another station during communication with one station, the
current communication is temporarily held. During this temporary holding
period, the identification information (telephone number) of the station
of the catch phone call is stored, and the communication being held is
restored. Upon completion of this communication, the station of the catch
phone call is called using the stored telephone number.
However, the prior art techniques disclosed in the above publications have
the following problems.
In the above prior art techniques, the communication concerned is not an
oral communication between persons, but a data communication between
machines such as facsimile apparatuses. In the case of such communication
between machines, even if it is held or suspended due to reception of a
catch phone call, it is guaranteed that the communication holding or
suspension state is maintained by the machine. Accordingly, it is easy to
automatically restore the communication with the previously communicated
station by executing a proper processing after completion of the interrupt
data communication.
On the other hand, when oral communication using an oral communication
means, i.e., a telephone unit attached to a data communication apparatus
is held due to a data transmission request, it is not guaranteed that the
person at the previously communicated station will stand by during the
data reception. The person may hang up the handset for some reason, or may
stand by as desired during the data reception.
Processings to be executed after completion of the data reception, i.e.,
after the interruption, are different depending on which of the above two
cases applies. For example, if the person at the previously communicated
station has hung up the handset, it is necessary to call him again,
whereas if he stands by, the circuit is restored simply by a hooking
operation.
Further, there is a possibility that the operator at the station will leave
the telephone unit in spite of the restoration of the circuit by, e.g.,
the automatic calling.
Thus, the conventional apparatuses do not fully consider a variety of
situations in the communication involving persons, and hence do not take
advantage of the catch phone service sufficiently.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a data communication
apparatus in which, when a data transmission request is made during
telephone communication, the communication is temporarily held to receive
the requested data, and thereafter the user can smoothly resume the
conversation with the previously communicated station in accordance with
the situation at that time point.
According to the invention, a data communication apparatus comprises means
for detecting completion of reception of data sent from a second station
which interrupted telephone communication between a first station and a
home station, and for outputting a hooking signal upon the completion of
the data reception.
Means are provided for performing hooking in response to the hooking
signal, to cause switching from a second telephone circuit for
communication with the second station to a first telephone circuit for
communication with the first station. Means are provided for detecting
busy tones to be received in response to the hooking, the busy tones
indicating that the first station has released the first telephone
circuit. Means are provided for releasing the first telephone circuit in
response to the detection of the busy tones.
Further, there may be provided means for automatically initiating a call to
the first station based on its stored dialing number, after the release of
the first telephone circuit.
Means may also be provided for notifying, in response to the hooking, an
operator at the home station that a telephone unit at the home station is
in an on-hook state.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing essential functions of a control unit
according to an embodiment of the present invention;
FIG. 2 is a block diagram of a facsimile system for explanation of a
hooking operation; and
FIGS. 3 and 4 include a flowchart of an interrupt post-processing.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described below in detail with reference to
the accompanying drawings.
First, a hooking operation for answering a catch phone call will be
explained. FIG. 2 shows a circuit of a facsimile system for explanation of
the hooking operation.
Referring to FIG. 2, a facsimile apparatus 1, a telephone unit 2 attached
thereto, and an exchange 3 are interconnected via a first relay 4 and a
second relay 5. In the illustrated state, the relays 4 and 5 are switched
to connect the exchange 3 and the telephone unit 2. Control signals for
switching the relays 4 and 5 are supplied from a control unit (not shown).
If, in the illustrated state, a connection request comes in from a
B-station 8 during telephone communication with an A-station 7 by use of
the telephone unit 2, a catch phone signal is sent from the exchange 3 to
the telephone unit 2. The catch phone signal is an intermittent signal of
400 Hz, which is audible to an operator who is in telephone communication.
Hearing this sound, the operator can recognize that the connection request
has come in from another station. Then, the operator performs a hooking
operation of just hanging up the handset for an instant. By this
operation, a contact 2a of the telephone unit 2 is opened for an instant,
and the exchange 3 detects instantaneous release of the telephone circuit
caused by this opening of the contact 2a.
Detecting the hooking from the instantaneous release of the circuit, the
exchange 3 switches the circuit from the A-station 7 to the B-station 8.
If the B-station 8 is a facsimile apparatus, the operator again performs
the hooking operation to switch the circuit to the A-station 7 and asks
the A-station 7 to hold the circuit. Thereafter, the operator again
performs the hooking operation to switch the circuit to the B-station 8,
and then instructs the facsimile apparatus 1 from, e.g., an operating
panel (not shown) to receive image data. In response to the instruction of
the operator, switching signals to switch the first relay 4 and second
relay 5 to the side opposite to the illustrated side are supplied from the
control unit, so that the B-station 8 and the facsimile apparatus 1 are
connected to each other.
Upon completion of the reception of image information by the facsimile
apparatus 1, the control unit supplies a signal to the first relay 4 to
open it, to effect an automatic hooking operation. Detecting an
instantaneous disconnection of the circuit caused by this hooking
operation, the exchange 3 switches the circuit from the B-station 8 to the
A-station 7.
In this way, the exchange 3 switches the circuit upon detecting the hooking
operation. When the circuit is switched to the A-station 7, the control
unit switches the first relay 4 and second relay 5 to the telephone unit
side, thereby connecting the telephone unit 2 and the A-station 7.
A monitor circuit 6 monitors whether the telephone unit 2 is in an on-hook
state where the handset is hung up or in an off-hook state where it is
not, from the open/closed state of the contact 2a. The function of the
monitor circuit 6 will be described later in more detail. It should be
noted that the switching of the telephone circuit that is executed in
response to the hooking operation is a well-known operation that is
carried out as part of the catch phone service.
By virtue of the above construction, the operator can resume the
conversation with a person at the A-station 7 after completion of the
interrupt operation caused by the catch phone call. However, if the person
at the A-station 7 has hung up due to some reason which prevented him from
waiting for completion of the interrupt operation, the circuit cannot be
connected to the A-station 7 in spite of the performance of the hooking
operation. Further, it may be the case that although the circuit is
successfully connected to the A-station 7, the operator may be away from
the home station, i.e., the station of the telephone unit 2.
Thus, it is necessary that an appropriate interrupt post-processing be done
in accordance with the situations at the home station and the other
station (i.e., A-station Interrupt post-processings to be executed in
accordance with each particular situation will be explained next.
A flowchart of FIG. 3 and 4 shows an interrupt post-processing.
Referring to FIG. 3, it is judged in Step S1 whether or not an interrupt
processing, i.e., reception of image data has been completed. This
judgement is made on the basis of a circuit disconnection signal DNC sent
from an interrupt station (i.e., B-station 8). If it is judged that the
interrupt processing has been completed, the process proceeds to Step S2.
In Step S2, an instruction signal to cause a hooking operation is output,
in response to which the first relay 4 is opened momentarily.
It is judged in Step S3 whether or not busy tones have been detected. When
the exchange 3 switches the circuit from the B-station 8 to the A-station
7 in response to the hooking, if the handset at the A-station 7 is hung
up, the circuit is not connected to the A-station 7 and the exchange 3
generates the busy tones. In other words, it is judged in Step S3 whether
or not the A-station 7 is holding the circuit based on whether or not the
busy tones have been detected.
If the busy tones have been detected, the process proceeds to Step S4,
where the circuit is released.
It is judged in Step S5 whether or not the dialing number of the A-station
7 is stored. This dialing number is the one which was input to initiate
the call to the A-station 7, and which was stored in a memory unit at that
time. It should be noted that in the case of communication performed
through an ISDN network, the dialing number of a calling station can be
recognized by the called-party station on the basis of the dialing number
information sent from an exchange. Accordingly, in such a case, the
dialing number information sent out from the exchange can be stored in a
memory unit.
If the judgement made in Step S5 is affirmative, the dialing number stored
in the memory unit is read out in Step S6, and then sent out (i.e., a call
is initiated) to the circuit in Step S7.
If the judgement in Step S3 is negative, which means that the A-station 7
has been holding the circuit and waiting, the process proceeds to step S8,
skipping Steps S4-S7.
In Step S8, it is judged whether or not the operator at the home station is
near the facsimile apparatus 1 and is able to resume the conversation.
This judgement is actually made by judging from a detection signal of the
monitor circuit 6 whether or not the handset is on the hook.
If the handset is not on the hook, which means that the operator at the
home station can resume the communication with the A-station 7
immediately, the process proceeds to Step S9, where the relays 4 and 5 are
switched to connect the telephone unit 2 and the circuit. Thus, the
interrupt post-processing is finished.
On the other hand, if the judgement in Step S8 is affirmative, it is known
that the operator at the home station is not prepared for communication,
though the A-station 7 is being called or already connected to the
circuit. Therefore, Step S10-S17 of FIG. 4 are executed to urge the
operator at the home station to lift the handset.
Referring to FIG. 4, it is first judged in Step S10 from a preset
instruction whether to ring a bell of the telephone unit 2. If the
judgement is affirmative, the process proceeds to Step S11, where a bell
energizing signal is output. The bell energizing signal is a signal of 16
Hz based on the same standards as those for a signal supplied as a
telephone call signal from a telephone company (e.g., Nippon Telegraph &
Telephone Company).
Where it has not been set to ring the bell, the process proceeds from Step
S10 to Step S12, where it is judged from a preset instruction whether to
ring a buzzer to urge the operator. If the judgement is affirmative, the
process proceeds to Step S13, where a buzzer energizing signal is output.
The buzzer may be one which is provided in the facsimile apparatus 1, and
may be based on any specifications. Therefore, the buzzer energizing
signal may be in any form, too.
Where it has not been set to ring the buzzer, the process proceeds from
Step S12 to Step S14, where it is judged from a preset instruction whether
to turn on a lamp to urge the operator to lift the handset. If the
judgement is affirmative, the process proceeds to Step S15, where a signal
is output to turn on the lamp to urge the operator to lift the handset.
Where it has not been set to turn on the lamp, the process proceeds from
Step S14 to Step S16, where it is judged from a preset instruction whether
to urge the operator to lift the handset by displaying letters. If the
judgement is affirmative, the process proceeds to Step S17, where a signal
is output to display, on a display unit, letters urging the operator to
lift the handset. The display unit is provided on the control panel of the
facsimile apparatus 1, for example.
If the judgement in Step S16 is negative, the process is finished.
After one of the bell energizing signal, buzzer energizing signal, the lamp
turning-on signal and the display signal is output, the process returns to
Step S8, where it is again judged whether or not the handset is on the
hook. In other words, a judgement is made as to whether or not the
operator has responded to a sign produced in response to one of the
above-described signals.
Although, in the above example, one of the ringing of the bell or the
buzzer, turning-on of the lamp, and display of letters is selectively
executed, the invention is not limited thereto, but all or any combination
of the means for urging the operator to lift the handset may be executed,
as shown by the broken lines in FIG. 4. In the latter case, the procedure
needs to be modified accordingly.
The functions of the control unit for executing the above-described
interrupt post-processing will be explained next. FIG. 1 is a block
diagram showing essential functions of the control unit.
Referring to FIG. 1, an interrupt completion detecting unit 9 constantly
monitors a protocol signal that is provided from a circuit control unit
(NCU) 10, to detect a circuit disconnection signal DCN sent from a station
under communication. When it is detected from the circuit disconnecting
signal DCN that transmission of image data from the other station has been
completed, a hooking instruction unit 11, responding to a detection signal
supplied from the interrupt completion detecting unit 9, provides a
hooking instruction signal to a hooking unit 12. The hooking unit 12
executes an instantaneous opening of the circuit in response to the
hooking instruction signal to inform, via the NCU 10, the exchange 3 of
the hooking. The hooking unit 12 is a means for opening the first relay 4
(see FIG. 2) for an instant.
A busy tone detecting unit 13 detects busy tones that are sent from the
exchange 3 in response to the hooking in the case where a previously
communicated station has released the circuit. A circuit releasing unit 14
provides a circuit releasing signal to the NCU 10 in response to the busy
tone detecting signal supplied from the busy tone detecting unit 13.
A dialing number memory unit 15 is a means for storing a dialing number of
the station with which communication was made before the start of the
interrupt processing. The dialing number is input from the operating unit
at the time of starting the communication with that station by initiating
a call. The dialing number stored in the dialing number memory unit 15 is
provided to a calling unit 16 in response to the busy tone detecting
signal supplied from the busy tone detecting unit 13. The calling unit 16
initiates a call via the NCU 10 based on the dialing number.
An on-hook judging unit 17 is a means for judging from an output signal of
the monitor circuit 6 (see FIG. 2) whether or not the telephone unit 2 is
in an on-hook state. The on-hook judging unit 17 outputs the result of the
judgement in response to the hooking executed after the interrupt
processing. The judgement result is supplied to one of a display control
unit 23, a buzzer driving unit 24, a lamp turning-on unit 25 and a bell
sound generating unit 18, via a closed one of associated selection
switches 19-22. The display control unit 23, buzzer driving unit 24, lamp
turning-on unit 25 and bell sound generating unit 18 output signals for
respectively instructing a display unit 26, a buzzer 27, a lamp 28 and a
bell incorporated in the telephone unit 2 to effect a desired display or
indication while the on-hook state is being detected by the on-hook
judging unit 17. The closure or opening of the selection switches 19 to 22
can be set in advance by the operator as desired.
The output of the bell sound generating unit 18 is provided to the
telephone unit 2 via the NCU 10.
Thus, in the above embodiment, the hooking signal is output after
completion of the interrupt processing, and then the circuit connecting
condition of the previously communicated station and the condition of the
handset at the home station are judged. If the circuit to the previous
station has been disconnected, the circuit to the home station is
temporarily released and thereafter the previous station is called. In
addition, if necessary, the operator at the home station is urged to
prepare for telephone communication.
Although in the above embodiment the selection switches 19-22 are provided
for selectively energizing the display unit 26, the buzzer 27, the lamp 28
and the bell of the telephone unit 2 as means for requesting the operator
to lift the handset when it is on the hook, it is possible to provide only
desired one or ones of the above means.
Although the above embodiment was described for such a case that image data
is received by a facsimile apparatus by interrupting a telephone
conversation, it is, of course, possible to execute a processing in the
same way as in the embodiment even where the interrupt request by a catch
phone call is for a data reception processing from other type of data
communication apparatus, e.g., a personal computer.
As is understood from the foregoing description, according to the
invention, it is possible not only to automatically carry out interrupt
communication caused by a catch phone call received during telephone
communication, but also to automatically restore the communication with
the previously communicated station by executing hooking upon completion
of the interrupt communication.
In resuming the telephone communication, an interrupt post-processing can
be executed in accordance with the situations at the previously
communicated station and the home station. More specifically, if the other
party has already released the circuit, a call to that station can be
automatically initiated on the basis of stored information on its dialing
number, whereas if the handset at the home station is on the hook, the
operator can be urged to lift it.
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