Telephonic communications – Special services – Call waiting
Reexamination Certificate
1998-01-30
2001-09-11
Matar, Ahmad (Department: 2642)
Telephonic communications
Special services
Call waiting
C379S201060, C379S093350
Reexamination Certificate
active
06289092
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to telephone switching methods and telephone switching apparatuses and, more particularly, to a telephone switching method and a telephone switching apparatus which utilizes a general switched telephone network to perform data communication and voice communication.
Recently, an increasing number of subscribers to a general switched telephone network connect a personal computer to a telephone line so as to perform data communication on, for example, the Internet.
Subscribers to the general switched telephone network are given an option of call waiting service in which a sound is produced while a user is engaged in a voice communication so as to indicate that there is an additional incoming call. Upon hearing the sound, the user can selectively communicate with a current partner or a new caller using a hook operation. Recently, the call waiting service has become extensively used.
In the call waiting service, the sound is superimposed on the current telephone line so as to notify the user of a new incoming call. If data communication is performed while the sound is being produced, the sound is superimposed on the data, resulting in damage to the data or an error in communication.
For this reason, the user is required to suspend the call waiting service while he or she is engaged in data communication.
2. Description of the Related Art
FIG. 1
shows an operation performed in the telephone switching method according to the related art.
When subscriber A performs an off-hook operation so as to dial a telephone number of subscriber B, an exchange
110
connects subscriber A to an exchange
120
to which subscriber B belongs. The exchange
120
calls the subscriber B using the telephone number dialed by subscriber A. When subscriber B responds to the call by performing an off-hook operation, subscriber A and subscriber B are connected to each other so that they can start voice communication.
When a call is originated by subscriber C to subscriber A via the exchange
110
, an interrupt is asserted to the voice communication between subscriber A and subscriber B in response to the call from subscriber C, if subscriber A subscribers to the call waiting service. A sound is provided to subscriber A indicating that there is a call from another party waiting.
By operating a hook, subscriber A can selectively talk with subscriber B or subscriber C.
A description will now be given of a connection to the Internet.
FIG. 2
shows a connection to the Internet according to the related art.
When subscriber A requests connection to the Internet using a personal computer
200
, the personal computer
200
activates a dialer so as to set a telephone line
210
to an off-hook status and dial an Internet service provider
220
.
The exchange
110
connects subscriber A to the exchange
120
to which the Internet service provider
220
belongs so that the exchange
120
connects to the Internet service provider
220
.
When a call is originated by subscriber C to subscriber A via the exchange
110
, an interrupt is asserted to the voice communication between subscriber A and subscriber B in response to the call from subscriber C, if subscriber A subscribes to the call waiting service. A sound is provided to subscriber A indicating that there is a call from another party waiting. Since subscriber A is engaged in data communication using the personal computer
200
, the data being exchanged during the communication may be damaged or an error may occur in the communication as a result of the sound being superimposed on the telephone line.
Some approaches to preventing damage to data or an error in communication from occurring as a result of an interrupt during data communication are proposed in Japanese Laid-Open Patent Applications No. 63-142755 and No. 64-71256.
A description will now be given, with reference to
FIG. 3
, of an approach disclosed in Japanese Laid-Open Patent Application No. 63-142755.
FIG. 3
shows an operation according to Japanese Laid-Open Patent Application No. 63-142755 for preventing damage to data or an error in communication from occurring due to an interrupt to data communication.
Referring to
FIG. 3
, Japanese Laid-Open Patent Application discloses registering in an exchange
300
a special number (for example, #
123
) for identifying data communication or facsimile communication. When data communication or facsimile communication is to be performed, subscriber A dials #
123
before dialing the telephone number of subscriber B. Upon detecting the special number #
123
at the beginning of the number dialed by subscriber A, the exchange
300
disables an interrupt from subscriber C while subscriber A is communicating with subscriber B.
A description will now be given, with reference to
FIG. 4
, of an approach disclosed in Japanese Laid-Open Patent Application No. 64-71256.
FIG. 4
shows an operation according to Japanese Laid-Open Patent Application No. 64-71256 for preventing damage to data or an error in communication from occurring due to an interrupt to data communication.
Referring to
FIG. 4
, Japanese Laid-Open Patent Application No. 64-71256 discloses providing in an exchange
400
a registration table
401
for registering telephone numbers of subscribers to whom an interrupt is permitted. By dialing a predetermined special number, a subscriber can make a registration in the registration table
401
(step S
3
-
1
).
Assuming that subscriber A is communicating with subscriber B (step S
3
-
2
) and there is a request for interrupt from subscriber C to subscriber A (step S
3
-
3
), the exchange
400
searches the registration table
401
storing telephone numbers registered by subscriber A in step S
3
-
1
(step S
3
-
4
).
If, as a result of the search in step S
3
-
4
, the telephone number of subscriber C is found in the registration table
401
, the exchange
400
enables the interrupt from subscriber C (step S
3
-
5
).
In this way, interrupts from only designated users are enabled.
Japanese Laid-Open Patent Application No. 63-142755 has a drawback in that operability suffers because a subscriber is required to dial a special number before making a call.
Japanese Laid-Open Patent Application No. 64-71256 requires maintaining registration tables for each of the subscribers, resulting in a large number of registration tables. Therefore, the approach disclosed in Japanese Laid-Open Patent Application is difficult to implement in the general switched telephone network. Since an interrupt from non-designated subscribers is enabled during data communication, such approach does not prevent damage to data and an error in communication. Another disadvantage is that the call waiting service is not available for ordinary voice communication for telephone numbers not registered in the registration. The call waiting service such as this lacks availability. Further, subscribers are required to perform a complicated operation in order to provide a registration table.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a telephone switching method and a telephone switching apparatus in which the aforementioned problems are eliminated.
Another and more specific object of the present invention is to provide a telephone switching method and a telephone switching apparatus in which damage to data in data communication is prevented.
The aforementioned objects can be achieved by a telephone switching method using a telephone switched network and provided with a call waiting service for producing an interrupt responsive to a call incoming to a first subscriber when the first subscriber is communicating with a second subscriber, comprising the steps of: identifying a destination number dialed by the first subscriber to originate a call, and determining whether the first subscriber is performing one of data communication and speech communication depending on the destination number identified; and suspending the call waiting service when it is determined that
Deane, Jr. William J.
Fujitsu Limited
Helfgott & Karas, PC
Matar Ahmad
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