JPH06164758A - Facsimile/telephone automatic changeover device - Google Patents

Abstract

PURPOSE:To preclude the possibility of malfunction due to a voice signal or malfunction due to a PB signal or the like with a simple circuit configuration by distinguishing a CNG signal, a voice signal, a non-voice signal through the logic between a signal detected via a 1100Hz notch filter and a signal detected directly. CONSTITUTION:When an incoming call signal from a telephone line L1/L2 is detected by an incoming call detection circuit 1, a CPU 5 throws a relay RL1 to the position of a contact M to acquire the telephone line L1/L2. Then the CPU 5 recognizes the CNG signal and the voice signal based on logic 1/logic 2 of signals detected by a signal detection circuit 2 via a 1100Hz notch filter 4 and a signal detection circuit 3 directly through the telephone line L1/L2. Thus, the CNG signal (facsimile communication start signal) is surely detected without malfunction due to a voice signal or a PB signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal facsimile connected to one telephone line and a telephone automatic switching device.

[0002]

2. Description of the Related Art In a conventional facsimile / telephone automatic switching apparatus of this type, when a call comes in from a telephone line, the line is once caught and a call signal for facsimile (hereinafter, CNG) which is an intermittent sound of 1100 Hz. (Abbreviated as signal) is detected, an automatic facsimile machine previously connected to the extension is called, and this machine seizes the line to establish a communication state.

However, when the calling side is not limited to the automatic facsimile machine and the calling is made by the telephone, when the calling side makes an intermittent sound by the voice of the person at the time of identifying the CNG signal, or again, the calling side. When a certain dial signal sound such as PB signal is intermittently sent out by some operation of, the CNG signal detection (1100 Hz) circuit erroneously detects it, and an error occurs when an incoming call is made to the automatic facsimile machine and a call state is set. There was a nature. In order to prevent the malfunction of the conventional switching device as described above, for example, Japanese Patent Laid-Open No. 3-2
Japanese Patent Laid-Open No. 95396 proposes and discloses an automatic selection call receiving device that implements the countermeasure.

[0004]

However, in the proposed structure as described above, in addition to the CNG signal detecting circuit, a PB signal detecting circuit, a 400 Hz signal detecting circuit, a facsimile network ringing signal detecting circuit and a voice signal detecting circuit. Etc., and their configuration / control was rather complicated and tended to be relatively expensive.

The present invention has been made in consideration of the above conventional situation, and has a relatively simple circuit structure.
It is an object of the present invention to provide an apparatus of this type capable of discriminating between an NG signal, a silent signal, a voice signal, and other signals such as a PB signal, and capable of performing a reliable facsimile / telephone automatic switching operation.

[0006]

Therefore, in the present invention, in a facsimile / telephone automatic switching apparatus for detecting a calling signal for facsimile and connecting to a facsimile, the calling signal is detected directly through a notch filter of 1100 Hz. It is intended to achieve the above-mentioned object by automatically connecting to the facsimile or the telephone by distinguishing the calling signal from voice and silence according to the logic of the same signal detection.

[0007]

With the above-mentioned device configuration, the voice and PB
The CNG signal can be reliably detected without causing an erroneous selection switching operation due to a signal or the like.

[0008]

EXAMPLES The present invention will be described below based on examples. FIG. 1 shows an embodiment of a CNG signal detecting circuit according to the present invention, and FIG. 2 shows an example of a frequency response characteristic curve of the notch filter.

(Structure) In FIG. 1, L1 and L2 are telephone lines, 1 is an incoming call detection circuit, 2/3 is a signal detection circuit 1 /
2 and 4, as shown in the frequency response characteristic curve of FIG.
It is a band-stop notch filter that produces a sharp notch in the 1100 Hz band. Further, RL1 indicates a relay controlled by a CPU 5 (not shown).

(Operation) Next, the operation in the configuration of FIG. 1 will be described. First, when an incoming signal from the telephone line L1 / L2 is detected by the incoming call detection circuit 1, the CPU 5 tilts the relay RL1 to the contact M side to capture the telephone line L1 / L2. Then, send the signal from the telephone line L1 / L2 side to 1
Logic 1 / logic 2 of each signal detection of the signal detection circuit 2 and the direct signal detection circuit 3 through the 100 Hz notch filter 4.
Thereby, the CPU 5 recognizes the CNG signal and the voice. That is; 1) Now, from the telephone line L1 / L2, a CN of 1100 Hz
When the G signal comes, the signal detection circuit 2 cannot detect the signal because of the notch filter 4, and the logic 1 is low (“L”).
As it is, the signal detection circuits 2 and 3 have the logic 2 high (“H”) for receiving the CNG signal.

2) Here, the telephone line L1 /
When there is no signal from L2 (silence state), the signal detection circuit does not receive the 2nd and 3rd signals, so that both logics 1 and 2 remain "L".

The above detection methods are summarized as shown in Table 1.

[0013]

[Table 1]

As described above, according to Table 1, voice malfunction and P
The CNG signal can be reliably detected without causing a malfunction due to the B signal.

(Example of Applied System) FIG. 3 is a block diagram of an example of a telephone exchange system to which the detection circuit of this embodiment is applied, and FIG. 4 is a block diagram of its main unit. This embodiment is a system capable of connecting 2 lines of external lines, 7 extension lines (telephone 6 and facsimile 1), 3 intercoms, security sensors for fire, gas, etc., and making outside line calls, incoming calls, hold transfers, and intercom calls. Here is an example.

In FIG. 3, reference numeral 21 shows an example of a main unit of a telephone exchange having a basic structure similar to that of the conventional example. TT ₁ and TT ₂ are two external lines (local line). ), 22 is an outer wall box. The main device 21 includes a protector 23, a sensor relay unit 24, a TV intercom interface unit 25, and the like. Also, 26, 27
Indicates a plurality of security (security) units, 28 indicates an emergency button, 29 indicates a fire sensor, and 30 indicates a gas sensor. T
_{1 to} T ₆ indicate six extension cordless handset devices. T ₁ and T ₂ are first and second security telephones, and T _{3 to} T ₆ are third to
6th extension phone, F is a facsimile (FAX)
Is. A TV intercom monitor unit 31 is connected to each of the security extension slave handsets T ₁ and T ₂ , and a speaker-equipped modular 32 is connected to each of the other ordinary slave handsets T _{3 to} T ₆ and the facsimile F. . On the other hand, D ₁ is the first intercom slave with TV camera, D ₂ , D
Reference numeral ₃ indicates the second and third intercom slaves.

Since FIG. 4 is a diagram for explaining the outline of the operation, the description of the detailed circuit will be omitted and only the essential parts relating to the operation will be described. 1) Incoming call from outside line The incoming signal from the outside line TT ₁ / TT _{2 is} monitored by the line,
A pseudo ring tone is sent from the outside line ring tone sending circuit 44, which is detected by the call incoming detection circuit 43a / 43b, passes through the call path switch 45, and each amplifier 46a / 46b / ... 46g.
When the off-hook of each cordless handset is detected by the passage monitoring circuit 41a / 41b ... / 41g, the ring tone is sent from the speaker modular speaker 32 of each terminal or the speaker of the dedicated telephone. The corresponding relay among the relays r1 to r7 or r8 to r14 is connected to the outside line TT ₁ / TT ₂ side.

2) Outgoing line transmission The dial from each child device is detected by the communication path monitoring circuit 41a or the PB receiver 42. The microphone processor 47 determines the meaning of the dial, and dials that have no meaning (for example, 1 to 1 for the extension dial). If 6, 7 and 8 are used, then 8, 9, 0, etc. are meaningless dials), it is judged as an outside line transmission, and relays r15 / r16 are set to contact M.
To the outside to capture the outside line TT ₁ / TT ₂ and PB sender 4
Send a dial to the outside line by 8/49. If a meaningful dial arrives, wait for, for example, 3 seconds for the second dial to come. If the second dial comes, it is judged as an outside line, The relay r15 is tilted to the outside line and the dial is sent out. When the outside line dial is completed, for example, the relay r1
To the outside line side, the relay r15 is turned off, and the outside line communication state is established. If the second dial does not come after waiting for 3 seconds, it is determined that the dial is an extension dial, and the extension 32 is called by voice from the modular unit with a speaker 32 of the dialed slave unit.

3) Facsimile / telephone automatic switching operation When the automatic switching mode is set by the special number operation from the slave unit, the following operation is performed, and the incoming signal from the outside line is detected by the incoming detection circuit 43a or 43b. To do.

The relay r15 is tilted to the M side to catch the outside line.

The CNG signal from the outside line is detected by the CNG signal detection circuit 52 by controlling the route select switch 50.

Based on the above, the following operation is performed depending on whether or not the CNG signal is detected; a) When the CNG signal can be detected: 1R generation circuit 51 is activated, relay r17 is tilted to the M side, and facsimile F When the call monitoring line 41g detects that the facsimile F automatically answers, the relay r7 is tilted to the B side (the side opposite to the M side at the time of calling), and the relay r14 is set to the outside line side (TT ₁ is the M side, TT). ₂ is B
Side) and then the relay r15 to the B side to connect the facsimile F to the outside line.

B) When the CHG signal cannot be detected The external ringing tone sending circuit 44 sounds the modular 32 with speaker of each slave and the dedicated telephone.

[0024]

As described above, according to the present invention, the automatic facsimile / telephone switching device is operated at 1100 Hz.
Since the CNG signal can be distinguished from the voice and the silence by the logic of the signal detection through the notch filter and the direct signal detection, the malfunction of the voice or the malfunction of the PB signal can be achieved with a relatively simple configuration / cost. It became possible to detect the CNG signal without fear and to perform automatic switching reliably.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a CNG signal detection circuit.

FIG. 2 An example of frequency response characteristic curve of the notch filter

FIG. 3 is a block diagram of an example of a telephone exchange system to which this embodiment is applied.

FIG. 4 is a block diagram of the main device.

[Explanation of symbols]

1 incoming call detection circuit 2/3 signal detection circuit 1/2 4 notch filter F facsimile T _{1 to} T ₆ telephone

Claims (1)

[Claims] 1. A facsimile / telephone automatic switching device which detects a calling signal for facsimile and connects it to a facsimile, by using the logic of the calling signal detection through a 1100 Hz notch filter and the direct detection of the calling signal. An automatic facsimile / telephone switching device is configured to automatically connect to the facsimile or telephone by distinguishing between voice and silence.