JPH0311706B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a limited incoming call system that allows incoming calls only from parties to whom the receiving subscriber has given encryption information in advance.

Background of the Technology Currently, telephones are widely used as a convenient means of daily communication, but in conventional telephone services, the existing telephone network basically connects the call path to the number specified by the calling subscriber. Since the calling party cannot select the party that will call, the calling party has priority.

Prior Art and Problems In conventional telephone services that give priority to the calling party, once the calling subscriber specifies the other party, the called party can receive a call at any time, except when the call is interrupted, and the user can pick up the receiver and make the call. There was an inconvenience in that it was impossible to confirm the identity of the person on the other end of the call unless the caller announced his/her name after the call had started, and it was not possible to select the person who had previously called and ring the bell or answer the call.

To solve this problem, it is sufficient if the calling party can know the identifying information of the calling party when a call is received.
To do this, it is necessary to transfer the calling party's identification information from the calling party to the called party before the call begins.
Existing telephone networks do not have that capability.

OBJECTS OF THE INVENTION The present invention provides a system for installing an additional device corresponding to a subscriber terminal of a destination subscriber line exchange, and receiving encrypted information entered by a calling subscriber in a provisional response state at the time of an incoming call.
The purpose of this system is to provide a system in which the receiving subscriber only allows incoming calls from desired parties through verification, and will be explained in detail below with reference to the drawings.

Embodiment of the Invention FIG. 1 shows an embodiment of the present invention, which is implemented by installing an additional device (hereinafter referred to as ADP) 6 corresponding to the destination subscriber terminal 4 of a subscriber line switch (hereinafter referred to as LS) 3. This shows the case where In addition, in an actual telephone network, an interruption switch may be installed between the originating and receiving LS,
Since there is no change in the operation sequence in the subscriber line, here, the originating telephone 1 and the terminating telephone 24 are
A case will be explained in which the following are accommodated in the same LS.

Originating subscriber line 2 and terminating subscriber line 5 in Figure 1
is usually composed of two wires, and the DC voltage conditions of the two wires depending on the connection state are as shown in FIGS. 2a to 2e. In other words, the normal state before the call is made (Fig. 2a)
Then, on both the originating and destination sides, L1 is + earth and L2 is -
It is 48V.

In Fig. 2 a to e, 1 indicates the connection of the telephone on the calling side and 24 indicates the connection of the telephone on the destination side, L1-L2.
The solid line connection between them indicates that the handset is off, and the dotted line connection indicates that the handset is off.
Indicates each status of ON. Further, FIG. 2b shows the DC voltage conditions of the subscriber lines L1 and L2 in the respective states in which there is an intention to make a call, c in which a dial signal is sent, d in which a call is being made, and e in which a call is in progress.

After off-hooking the calling telephone 1 in Figure 1,
When you dial the phone number of the destination phone 24,
A ring tone is sent from the LS3 to the calling side and a ringing signal is sent to the called side, and the polarity of the called side subscriber line 5 is reversed, L1 becomes -48V and L2 becomes + ground (during the call). Figure 2 d). Up to this point, there is no difference in the connection operation of a conventional telephone.

When the incoming call detection circuit 8 of ADP6 detects this inversion, the output 19 of the incoming call detection circuit 8 causes the CPU1 to
3 is notified of the incoming call, and a temporary response is made by forming a one-way loop in which current flows only in the direction of L2→L1 in the temporary response circuit 9. The inversion detection in the incoming call detection circuit 8 can be easily realized using, for example, a general-purpose comparator circuit, or a method may be adopted in which the call signal sent from the LS 3 is detected simultaneously with the inversion. Temporary response circuit 9
can be easily constructed using, for example, a diode that allows current to flow in the direction of L2→L1 and a series resistor. Also L2
→By combining a phototransistor or the like with the configuration of a diode and series resistor that allows current to flow in the direction of L1, it is also possible to simultaneously execute both the functions of the temporary response circuit 9 and the incoming call detection circuit 8.

Provisional response is a technology implemented in the trunks of existing telephone networks for toll-free incoming calls, and the calling subscriber is not charged, thereby preventing losses on the calling side. This is an existing, well-known technique, and a detailed explanation will be omitted here, but in the state after a provisional response,
The DC voltage conditions of the subscriber line are the same as those in Fig. 2 a to c, the ring tone and ring signal are stopped, and a communication path is formed between the calling telephone 1 and the ADP 6 without starting billing. .

The outline of the provisional response operation has been explained above, but since the actual operation is executed almost instantaneously, the time it takes for the ringing tone and ringing signal to be sent from the LS3 to the calling telephone 1 and the receiving telephone 24, respectively, is very short. ,
In reality, it is close to 0, so LS on caller phone 1
The ringing tone sent from 3 is almost inaudible.
In the above explanation, an example was explained in which the calling subscriber is not charged in the case of provisional response, but the provisional response circuit 9 creates a two-way loop (the same loop as the conventional call response).
It is also possible to create a system and charge charges from the time of provisional response.

When the CPU 13 is notified of the incoming call by the output 19 of the incoming call detection circuit 8, the CPU 13 operates the guidance sending circuit 12 by the output 22 of the CPU 13, and sends guidance from the ADP 6 to the calling telephone 1 requesting input of encrypted information. . The guidance sending circuit 12 can be easily realized using, for example, a voice synthesis LSI, or may use an IC that creates tone signals within the voice band.

The originating subscriber listens to the guidance and enters encrypted information. The specific means (signal) used to input the encrypted information may be anything as long as it can be transmitted within the voice communication band of the telephone; for example, a pushphone dial signal (hereinafter referred to as PB signal).
etc. may be used as is. The case of the PB signal will be explained below as an example. As the encrypted information, for example, a four-digit number such as that used in automatic cash payment services of banks can be used. To input a PB signal, if the calling phone 1 is a push phone, you can simply press the dial button, or if it is a dial pulse phone, you can press a portable acoustic coupler type PB transmitter against the transmitter. May be used.

The encrypted information based on the PB signal sent from the calling phone 1 is transferred to the ADP 6 and sent to the PB signal receiver 7.
The output of the PB signal receiver 7 is sent to the CPU 13.
will be forwarded to. The memory 14 stores encrypted information that has been registered in advance by the called subscriber and is used to select a party to whom incoming calls are permitted.
The CPU 13 compares the encrypted information transferred from the PB signal receiver 7 with the encrypted information stored in the memory 14, and if the two match, the called subscriber accepts the call from the other party. It is recognized as an incoming call, operates relay A17, drives contact a downward, and sends a calling signal from the calling signal sending circuit 15 to the called telephone 2.
At the same time, the output 20 of the CPU 13 operates the ringing tone sending circuit 10 to send a ringing tone to the calling party.

The called telephone 24 receives the calling signal and rings the bell. When the called subscriber responds by going off-hook, the subscriber response detection circuit 16 detects this and uses the output 23 of the subscriber response detection circuit 16 to send a response to the CPU 1.
3 of the subscriber response. In response to this, the CPU 13 deactivates the relay A17, restores the contact a, stops sending out the calling signal, creates a bidirectional loop (the same loop as the conventional call response) in the destination subscriber line 5, and at the same time The operation of the ring tone sending circuit 10 is stopped by the output 20 of the CPU 13.

When a loop is created in the destination subscriber line 5, the polarity of the originating subscriber line 2 is reversed as shown in Figure 2e, L1 becomes -48V, L2 becomes + ground, and billing begins. and at the same time, the calling phone 1 and the calling phone 2
You can make calls up to 4.

PB signal receiver 7 to output 1 of PB signal receiver 7
If the encrypted information transferred to the CPU 13 by 8 and the encrypted information stored in the memory 14 do not match, it is assumed that the incoming call is from a party that is not permitted by the called subscriber, and the busy tone sending circuit 11 is activated by the output 21 of the CPU 13. When activated, a busy tone is sent to the calling party, and no ringing signal is sent to the telephone 24 of the called party. Note that the busy tone when incoming calls are not permitted may be a system in which the guidance sending circuit 12 sends a message such as ``You cannot connect to this subscriber'' by voice, for example.

The series of control operations described above can be easily realized by controlling the CPU 13 by software.

Effects of the Invention As explained above, according to the present invention, by installing an additional device corresponding to the subscriber terminal of a subscriber desiring service of an existing telephone network, a call can be received from a party desired by the called party. As a result, instead of the telephone service where priority was given to the calling party, it is now possible to quickly provide a service in which the receiving party has the right to choose, and without having to make large-scale modifications to the existing telephone network. Can be provided. Moreover, since the PB signal is used for the encrypted information for selecting the called party, the calling subscriber can directly send the encrypted information from a normal push-button dial telephone, such as a push-button dial public telephone, even when away from home. It is possible to realize a system with good service performance for side subscribers as well. By implementing the present invention, a significant effect can be expected in preventing intimidation and harassing phone calls that abuse the telephone service that gives priority to the caller. Furthermore, by applying it to telephones within a specific company, it becomes possible to configure a type of closed communication network using the public telephone network.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the connection operation of a subscriber line exchange. 1... Originating telephone, 2... Originating subscriber line, 3...
...Local line exchange (LS), 4...Destination subscriber terminal, 5...Destination subscriber line, 6...Destination side additional device (ADP), 7...PB signal receiver, 8...Incoming call Detection circuit, 9... Temporary response circuit, 10... Ringing tone sending circuit, 11... Busy tone sending circuit, 12... Guidance sending circuit, 13... CPU, 14... Memory, 15... Ringing signal sending circuit, 16...Subscriber response detection circuit, 17...Relay A, 18...
Output of PB signal receiver 7, 19...Output of incoming call detection circuit 8, 20-22...Output of CPU 13, 2
3... Output of subscriber response detection circuit 16, 24...
Terminating phone.

Claims (1)

[Claims] 1. In an automatic telephone switching system, a means for registering and storing cryptographic information in advance for allowing a called subscriber to receive a call, a means for detecting the received call, and a means for detecting the received call, corresponding to the subscriber terminal of the subscriber line exchange on the called side. provisional response means for setting up a communication path with the originating subscriber by forming a loop and provisionally responding without starting charging to the originating subscriber based on the output of the means; means for transmitting guidance for requesting encrypted information input to the calling party after setting the route;
After listening to the guidance, the caller enters the encrypted information,
means for receiving the encrypted information transferred from the input calling party; means for comparing the received encrypted information with the pre-registered/stored encrypted information; 1. A limited call reception system characterized by being provided with an additional device having means for connecting both subscribers on the originating side and on the terminating side only when certain cryptographic information matches received cryptographic information.