JPH083088Y2 - Busy sound blocking device for multi-line simultaneous calling equipment - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a busy sound blocking device for a multi-line simultaneous calling device.

[0002]

2. Description of the Related Art Teleconferences by a plurality of people between remote locations, neighboring locations, and indoor locations using a telephone line are already well known and conducted. In this case, generally, a multi-line simultaneous calling device that mixes the voices of a plurality of used telephone lines into one is used. It has a plurality of line connection circuits to be connected, and has a plurality of two-wire to four-wire conversion circuits that respectively divide the common lines for transmission and reception of these line connection circuits into the transmission line and the reception line. It has one voice mixing circuit which distributes each transmission signal inputted to all reception lines. Therefore, when the telephone line connected to each line connection circuit becomes in the call state, that is, the ON state, the transmission signal sent from any one of the telephone lines will be transmitted through the line connection circuit, the two-wire four-wire conversion circuit, and the transmission line. After that, it enters the voice mixing circuit, is distributed to each receiving line related to all other ON-state telephone lines in the voice mixing circuit, and goes into the ON state through each two-wire / four-wire conversion circuit and line connection circuit. Sent to all other phone lines. In other words, in all of the connected telephone lines that are in the ON state, the voices can be mixed into one and a plurality of simultaneous calls can be made.

[0003]

[Problems to be solved by the invention] However, in a telephone with a telephone line in an OFF state that does not participate in a plurality of simultaneous calls, if the handset is floating from the main body of the telephone,
A known busy tone (visit tone) is generated to notify this. This busy tone is a voicing of the electrical signal (busy tone signal) generated by it, but this busy tone signal sometimes does not stop at the line concerned, It circulates to the telephone line of
It causes discomfort. Therefore, the present invention aims at promptly blocking the intruding busy tone signal and promptly eliminating the line of the busy tone signal intrusion source.

[0004]

[Means for Solving the Problems] In order to achieve such an object,
According to the present invention, a plurality of line connection circuits 1 for individually connecting a plurality of wire communication lines are provided, and a plurality of common lines for transmission and reception of these line connection circuits are respectively assigned to a transmission line a and a reception line b. In the multi-line simultaneous call device, which is provided with the two-wire / four-wire conversion circuit 2 ... And has the voice mixing circuit 3 which distributes each transmission signal input to the transmission line a ... to all the reception lines b ... A volume attenuator 4 capable of narrowing down the line signal is interposed in each of the transmission lines a.
Further, the band-pass filters 6 for detecting busy sounds in the line signals from the input side of the volume attenuators of the respective transmission lines a.
Further, by receiving a busy tone detection signal from these band-pass filters 6 ..., all of the volume attenuators 4 ... Are instantaneously narrowed down and the corresponding line is discriminated and the line connection circuit 1 of this is cut off. It is characterized in that a CPU 5 is provided.

[0005]

With the above-described structure, in use, as in the conventional case, the plurality of line connection circuits 1 are connected to the wire communication lines (telephone lines and other communication lines) (1), (2) ,.
(N) may be connected to be used for a plurality of simultaneous calls, but during the plurality of simultaneous calls, one of the OFF-state lines (for example, (1)) not participating in this talk caused by the floating of the handset. When the middle tone signal enters, the middle tone signal instantly enters the voice mixing circuit 3 through the line connection circuit 1, the two-wire / four-wire conversion circuit 2, the transmission line a, and all other circuits. Will be distributed to. However, at the next moment, each bandpass filter 2
... detects the busy signal, and the CPU 5 receiving the signal immediately narrows down the volume attenuators 4 for about 0.1 seconds.
Calls will be interrupted during this narrowing down, but since it is only a moment, it cannot be discerned by the human ear. Also,
During this narrowing down, only one band filter 6 of the busy sound intrusion line continues to detect the busy sound signal, and as a result, the busy sound intrusion line can be identified, and the CPU 5 determines this. The determination is made to shut off the line connection circuit 1 of the corresponding wire communication line and exclude the line . That is,
In the relevant line connection circuit 1, the disconnection (exclusion)
Holds and keeps blocking the intrusion of the busy signal after that,
It does not interfere with simultaneous calls. In addition,
As a result, the band-pass filter 6 of the line transmits the busy tone signal.
Since it will not detect it, the CPU 5 can also return to the original state.
However, the relevant line connection circuit 1 shuts off by holding itself.
Because it lasts,
Absent. This interruption is automatically restored in the line connection circuit 1 when the receiver returns to the normal OFF state and the busy signal disappears. In the regular multiple simultaneous call state, each line connection circuit 1 ...
When the wired call lines (1), (2), ... (n) connected to the line are set to the call state, that is, the ON state, the transmission signal sent from any one of the wired call lines is the line connection circuit 1 or 2 concerned. It enters the voice mixing circuit 3 through the line-to-four line conversion circuit 2 and the transmission line a, and is distributed to the reception lines b ... Of all other wire communication lines in the ON state in the voice mixing circuit, and It is transmitted to all the other wire communication lines in the ON state via the two-wire / four-wire conversion circuit 2 and the line connection circuit 1.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above construction, for example, a DA converter is used as the volume attenuator 4.

[0007]

EFFECTS OF THE INVENTION According to the present invention, even if a busy sound signal intrudes from any of the wire communication lines, it can be stopped by a momentary narrowing down of each volume attenuator 4 ... The intruding line can be specified by means of this, and thus the line connection circuit 1 can be cut off to eliminate the wired call line. Of course, its operation is instantaneous, so it cannot be discerned by the human ear, and the busy tone is heard. I can't hear. Therefore, the intended purpose can be achieved, and the busy signal does not disturb the call or cause discomfort. Moreover, the structure and the manufacturing are simple and the cost can be provided, which is practically useful.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit of an embodiment of the present invention.

[Explanation of symbols]

 1 line connection circuit 2 two-wire to four-wire conversion circuit 3 voice mixing circuit 4 voice attenuator 5 CPU 6 band filter a transmission line b reception line

Claims (1)

[Scope of utility model registration request] 1. A plurality of line connection circuits 1 for individually connecting a plurality of wired telephone lines are provided, and a plurality of common lines for transmission / reception of these line connection circuits are assigned to a transmission line a and a reception line b, respectively. The two-wire-four-wire conversion circuit 2 ...
In a multi-line simultaneous communication device provided with a voice mixing circuit 3 for distributing each transmission signal input to those transmission lines a ... To all reception lines b ..., Line signals are narrowed down to each transmission line a ... .. are provided, and band filters 6 are provided for detecting busy sounds in the line signals from the input side of the volume attenuators of the respective transmission lines a .. A CPU 5 is provided, which receives a busy tone detection signal from the filters 6 to instantaneously narrow down all of the volume attenuators 4 ... And discriminates a corresponding line to shut off the line connection circuit 1. This is a busy sound blocking device for multiple line simultaneous calling equipment.