JP2520417B2 - Call weighting service system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a call waiting service system in data communication using a telephone switching network, and in particular, a data terminal exchanges data with a center or another data terminal. The present invention relates to a call waiting service system in which, when a terminal receives an incoming call from a third party during communication, the fact is displayed on the data terminal.

[Conventional technology]

In the conventional call waiting services, as described in, for example, U.S. Pat.No. 3,714,378, when a call is received during a call, the call connection is intermittently disconnected and the called side is intermittently switched and connected to a special service common circuit. When the incoming call signal is transmitted to the called party in the state of being in the state, the fact is displayed.

[Problems to be solved by the invention]

However, the above-mentioned call waiting service is related to a voice call, and is not suitable for application to an incoming call from a third party during data communication using a call connection. This is because when a data terminal in a data communication state receives an incoming call from a third party, it is assumed that the subscriber of the data terminal is a call waiting service contract registrant, Even if an incoming call signal as an audible tone is sent, the incoming call signal cannot be displayed as an audible tone in the data terminal itself, unlike the attached telephone, and therefore the subscriber Not only cannot know the fact of the incoming call from the third party, but because of the superposition of the incoming call signal during the call to the modem carrier, and above all, the disconnection of the call during the data communication causes a data error. This is because that. However, since a data error also occurs due to a line error, it is impossible for the subscriber of the data terminal to distinguish whether the data error is due to the line error or the incoming signal during communication. Because.

Incidentally, here, a brief supplementary explanation of the incoming call signal will be that the incoming call signal itself is originally prepared for a telephone (a telephone terminal) (in a call state). On the other hand, as a subscriber terminal, it is a well-known fact that recently, in addition to a telephone terminal, a data terminal (such as a personal computer) can be switched and connected to the same subscriber line at any time and data communication is performed. . By the way, the current exchange does not have a data communication / call state identification function, and from this point of view, the data communication state of the data terminal must be regarded as the telephone call state of the telephone terminal. Even when the side receives an incoming call from a third party during data communication, the incoming call signal is unconditionally transmitted to the called side.

An object of the present invention is to provide a call waiting service system that can display to the called party when the called party receives an incoming call from a third party during data communication.

[Means for solving problems]

If an incoming call from a third party is made to the data terminal side while the data terminal is performing data communication with the other party (communication partner) via the switching network in the full-duplex system, the data terminal side is called. Uses the fact that the carrier from the data terminal is not sent to the other party while the line is cut off intermittently so that the incoming call signal can be sent during the call. The incoming call can be displayed on the data terminal from the beginning.

In other words, when the other party detects that the carrier is disconnected due to the incoming call signal, the other party determines that it is an incoming call to the data terminal and then periodically sends a message to that effect to the data terminal. It is achieved by sending to.

[Work]

When there is an incoming call to the data terminal during a call, the incoming call signal is periodically sent to the data terminal, but while the incoming call signal is being sent, the other party detects carrier disconnection from the data terminal. Will be done. Therefore, when carrier disconnection is detected periodically, the other party determines that it is due to an incoming call signal to the data terminal and then sends a message to that effect to the data terminal. is there. Even if the incoming call signal is being sent to the data terminal periodically, if the other party sends a message periodically, the message will leave a gap (gap) between the incoming call signals. It can be displayed on the data terminal without fail, and the incoming call during call can be known on the data terminal side from the transfer display.

〔Example〕

 Hereinafter, the present invention will be described with reference to FIGS.

First, the data communication network according to the present invention will be described.
FIG. 2 shows a network configuration as an example. In this example, the data terminal 10 including the telephone 9 as shown in the figure is configured to perform data communication with the center 1 via the telephone exchange 8 and the relay telephone exchange 7 by the full-duplex method. As a data communication partner, a general data terminal other than the center 1 can be considered. Data terminal 10
When a general data terminal or a center 1 including a carrier detection function is provided with a carrier detection function, a call reception during a data communication from a third party is surely a destination of the data terminal or the center 1.
Can be displayed on.

In this example, it is assumed that the data terminal 10 receives an incoming call, so that the center 1 is provided with a carrier detection function in advance. This function is provided in the modem 2, and the center 1 transmits / receives data to / from the modem 2 via the data transmission / reception line 3, while the carrier detection signal (CD) from the modem 2 via the carrier detection signal line 4.
Is to be received. It is possible to determine that the data terminal 10 is connected to the center 1 while the carrier detection signal is obtained.

Here, while data communication is being performed between the center 1 and the data terminal 10, an incoming call from a third party is received by the data terminal 10
If so, the telephone exchange 8 sends an incoming call indication sound as an incoming call signal to the data terminal 10 every 4 seconds for a fixed time (about 700 ms to 1600 ms). While the call path is cut off while the incoming call indication sound is being sent, the data sent during that time becomes an error, but the modem 2 on the center 1 side detects the carrier from the data terminal 10 while the incoming call indication sound is being sent. Not activated, carrier detection signal (CD) is OFF
It will be obtained as a state. Therefore, for example, by detecting that the (CD) of the carrier detection signal is in the OFF state for a fixed time (about 700 ms to 1600 ms) within 4 seconds, the transmission of the incoming call signal to the data terminal 10 is detected. It is possible to do.

In this example, as shown in the figure, the state of the carrier detection signal (CD) is read at a constant cycle (for example, 200 ms) and then sequentially stored in the shift register 5. The shift register 5 has a length of N bits (for example, N = 25),
Since the state of the carrier detection signal (CD) is shifted by 1 bit each time it is written from the center 1, therefore, the shift register 5 is in the state of the carrier detection signal (CD) within the immediately preceding constant period (for example, 5 seconds). Will be remembered.
The state of this carrier detection signal (CD) remains ON while there is no incoming call during a call, but when there is an incoming call during a call, the ON and OFF states are repeated as shown in Fig. 3. The incoming call during the call to the data terminal 10 can be known from the state change. Although the OFF state is shown as "1" in FIG. 3, the count 6 indicates the number of states of the "1" in the shift register 5 every time the carrier detection signal (CD) is shifted and stored in the shift register 5. It is supposed to be displayed as a count. Therefore, the count value of the counter 6 indicates the OFF state time (= count value × 200 ms) of the carrier detection signal (CD) within the last 5 seconds. The OFF state time of the carrier detection signal (CD) due to the incoming call indication sound is about 700 ms to 1600 ms in a 4-second cycle, so as the OFF state time within an arbitrary continuous section over 5 seconds, the sending time of the incoming call indication sound is about In the case of 700 ms, the minimum is about 700 ms, and when the sending time is about 1600 ms, the maximum is about 2600 ms. Therefore, after all, the count value of the counter 6 is 3 to
Within the range of 13 (actually, the relationship between the reading time of the OFF state and the sending start time of the incoming call indicator sound is indefinite, and the error of the sending time of the incoming call alert sound itself is taken into consideration. It is desirable that the upper limit of the count value be set to 15, and even if such an upper limit is set, no problem will occur in practice.) I will get it.

By the way, if the line is interrupted for a few hundred ms,
The carrier detection signal (CD) is temporarily turned off (the count value of the counter 6 is equivalent to 1 or 2), while if the line is disconnected, the off state continues and the line The count value of the counter 6 gradually increases from 0 after the start of the disconnection, and the count value becomes 25 after 5 seconds. Therefore, when the line is disconnected, the same state as the sending of the incoming call indicator sound only appears transiently or temporarily, so if the continuous state of that state is monitored, that state will be received. It is possible to prevent erroneous detection as the sending state of the display sound.

FIG. 1 shows a flow of an example of a call waiting service process according to the present invention in a center.
In this case, when the communication is started, the processing in the center 1 enters the state of monitoring the incoming call display sound, and the processing is continued for a certain period (for example
Second, the value of the counter 6 is verified, and when an incoming call is detected by this, the incoming call display sound continues. This state is provided to determine whether there is a momentary disconnection or a line disconnection. If the incoming call continues for 5 seconds, it is determined that there is an incoming call by a third party, and then a call waiting message is sent to the data terminal 10. After sending, the call waiting message is displayed. This state is provided in order to prevent the call waiting message from temporally colliding with the incoming call display sound and resulting in an error and not being received by the data terminal 10. While the value of the counter 6 indicates an incoming call, The call waiting message is transmitted to the data terminal 10 every one second.

On the other hand, when the call-waiting message is received and displayed on the data terminal 10, the operator switches the line to the telephone 9 and then hooks, but when a flicker is detected, the telephone exchange 8 connects to a third party. Will be the place to do. Therefore, in the center 1, the value of the carrier interruption counter 6 from the data terminal 10 becomes large, but when the value becomes large, the center 1 judges that the carrier detection signal (CD) is disconnected and shifts to the pending state. There is. The line is released when the carrier detection signal (CD) disconnection continues for 30 seconds during the hold, but when the line is connected to the data terminal 10 by rehooking at the telephone 9 within 30 seconds, the carrier detection signal ( The ON state of CD) is detected, and data communication can be performed again.

As described above, according to the present invention, even during data communication, the call waiting service can be implemented by detecting the carrier disconnection due to the incoming call display sound and notifying the operator.

〔The invention's effect〕

As described above, according to the present invention, when there is an incoming call from a third party to a data terminal in a data communication state, the incoming call signal from the exchange is replaced on the data terminal. As a matter of course, since the call waiting message from the communication partner can be displayed, the subscriber can talk with the third party even during the data communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of an example of a call waiting service process according to the present invention, FIG. 2 is a diagram showing a network configuration of an example of a data communication network according to the present invention, and FIG.
FIG. 6 is a diagram for explaining a method for detecting an incoming call during communication based on detection of carrier disconnection. 1 ... Center, 2 ... Modem, 5 ... Shift register,
6 ... Counter, 7,8 ... Telephone switch, 9 ... Telephone, 1
0 …… Data terminal.

Claims (1)

(57) [Claims] 1. A data terminal to which a telephone terminal is attached via a telephone switching network, in a state where data communication is performed by a full-duplex method with a communication partner having a carrier detection function. A call waiting service system in which the fact that the call is received is notified from the communication partner to the data terminal when a call is received from a third party to the data terminal. In the state where data communication is being performed with the other party, when an incoming call from the third party to the data terminal is in the data terminal accommodating exchange, the exchange intermittently connects the call to the data terminal. Due to such disconnection, when an incoming call signal as an audible tone is periodically sent from the exchange to the data terminal for a certain period of time, the communication partner sends the key to the carrier from the data terminal. Based on the rear intermittent pattern monitoring result, when the carrier disconnection factor from the data terminal is indirectly detected as due to the above-mentioned incoming call signal, the incoming call signal is detected by the communication partner. While a call waiting message is periodically transmitted from the communication partner while the communication partner is on the communication terminal, the call waiting message is allowed to be received in the non-disconnection section on the call connection at the data terminal. Call-waiting service method to be displayed.