JPS634739B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for time-division multiplexing voice signals and information in other forms by transmitting information in a form other than voice during voice pause periods, and transmitting the same over the same telephone line simultaneously. In recent years, with the diversification of communications, there has been a demand for the ability to simultaneously send information other than voice, such as handwritten information such as simple memos and sketches, and data signals, while talking on the telephone. This can be achieved by frequency modulating or amplitude modulating non-voice information and frequency division multiplexing it with the voice within the voice band. Alternatively, during a voice call, during a pause period, non-voice information is A time-division multiplexing method that sends out is considered. In the frequency division multiplexing method, the bandwidth currently allocated to voice is 300 to 3300Hz, which is relatively narrow, and if a band for information other than voice is allocated within this band, it will be possible to increase the bandwidth of voice. Since the bandwidth has to be narrow, there is a drawback that the communication quality, such as clarity and sound quality, is significantly degraded. In addition, the method using time division multiplexing has the drawback that mismatches in pause detection tend to occur due to line loss, noise, etc., which frequently causes audio to be cut off, resulting in deterioration in call quality. This invention has been made to overcome the above-mentioned drawbacks, and therefore, the purpose of this invention is to:
To provide simultaneous transmission of voice information and other information in other forms without impairing call quality. This invention is directed to the malfunction of silence detectors (pause detection) installed at both ends of the transmission line when transmitting voice information and non-voice information carried by a modem, etc. in a time-sharing manner using a single voice line. In order to eliminate communication errors and modem sounds flowing into the handset, the system compensates for line loss that causes pause detection malfunctions and controls the time-division transmission of non-voice information and voice. This is how it was done. The drawings will be explained in detail below. In the embodiment, time division multiplexing control of audio signals and image signals such as handwritten characters and figures will be described, but the same method can also be applied to data and narrowband image signals other than image signals such as handwritten characters and figures. It is clear that time-sharing control can be implemented. FIG. 1 shows an embodiment of the present invention, in which 1 is an audio signal input terminal, 2 is an audio signal output terminal, 3 is a hybrid coil, 4 is a changeover switch, 5 is a hybrid coil, 6 is a telephone line terminal, and 7 is a a changeover switch; 8 is an audio signal delay circuit; 9 is an image signal input terminal for handwritten characters and figures; 10 is an encoder;
11 is a transmitting side buffer memory, 12 is a full-duplex modem, 13 is a hybrid coil, 14 is a receiving side buffer memory, 15 is a decoder, 16 is an image signal output terminal, 17 is a receiving modem carrier level detector, and 18 is a variable preset type. amplifier; 19 is a pause detector; 20 is a control unit; 21 is a transmission audio signal;
22 is the received audio signal after amplification, 23 is the pause detector output, 24 is the carrier detection output of the modem, 25
is the data storage amount detection result output of the transmission buffer memory, 26 is a control signal from the communication between modems from the other party, 27 is a control signal for changeover switches 4 and 7, 28 is a pause detector reset control signal, 29
is a modem control signal, 30 is a received signal, 31 is a modem carrier level detector output, 32 is a received audio signal, and 33 is a modem output signal. 2 and 3 are explanatory diagrams of the present invention, and A is A.
B is the time chart of the B-side terminal, C and C' are the output signals 27 of the control section, D and D' are the output signals 23 of the pause detector 19, and E and E' are the output signals 23 of the pause detector 19. The output signals 33, F and F' of the modem 12 are the output signals 26, F and F' of the decoder 15,
G and G' are carrier detection output 2 of modem 12
4, a and a' are control signal states that connect the changeover switches 4 and 7 to the side a in FIG. 1, b and b' are control signal states that connect the changeover switches 4 and 7 to the side b in FIG. d and d' are the output signals 23 of the pause detector 19 when no pause is detected, e and e' are the output signals 23 of the pause detector 19 when a pause is detected, and f and f' are the output signals 23 between the modems. special command signal for synchronization, g
and g' are signals of other information, h and h' are special command signals to terminate communication between modems, i and i' are states in which command signals g and g' are detected,
j and j' are states in which command signals h and h' are detected, k and k' are states in which a modem carrier of the other party is detected, and l and l' are states in which no carrier is detected. First, FIG. 1 will be explained. The transmission audio signal is input from the transmission audio input terminal 1, passes through the hybrid coil 3, the a side of the changeover switch 4, and the hybrid coil 5, and is output to the telephone line terminal 6. The received audio signal is input from the telephone line terminal 6, and is sent to the hybrid coil 5, the a side of the changeover switch 7,
Audio signal delay circuit 8 and hybrid coil 3
The signal is then output to the audio signal output terminal 2. The transmission image signal is input to the image signal input terminal 9, encoded by the encoder 10, temporarily stored in the transmission buffer memory 11, modulated by the modem 12, and sent to the hybrid coil 13 and the changeover switch 4.
The signal then passes through the hybrid coil 5 and becomes the output of the telephone line terminal 6. The received image signal is input from the telephone line terminal 6, passes through the hybrid coil 5 and the hybrid coil 13, becomes input to the modem, is demodulated, passes through the reception buffer memory 14 and the decoder 15, and becomes the output of the image signal output terminal 16. A transmitted audio signal 21 and a received audio signal 22 are input to the pause detector 19, and pause detection is performed on the sum of the two. Generally, the received audio signal suffers from rotation loss, and therefore the signal levels applied to the pause detectors installed at both terminals are different, resulting in different pause detection results between the opposing terminals. Therefore, the level of the modem carrier from the other party is detected using carrier level detector 1.
7 and adjusts the amplification degree of the preset type variable amplifier 18 according to the absolute level of this carrier, thereby equivalently compensating for the line loss affecting the received audio signal and preventing discrepancies in pause detection. There is. The control unit 20 receives a pause detector output 23, a carrier detection output 24 of the modem, a data storage amount detection result output 25 of the transmission buffer memory, and a control signal 26 from the other party through inter-modem communication.
The control section 20 controls the changeover switches 4 and 7 according to these signals. The relationship between the input to the control section 20 and the control outputs of the changeover switches 4 and 7 is shown in the following table.

[Table] The control unit 20 switches the contacts of the switching devices 4 and 5 when the carrier of the other party is detected, when the pause detector 19 detects a pause, and when the amount of data accumulated in the transmission buffer memory is above a certain threshold. to the b side and start communication between modems (types 4 to 8 in the table above). Note that when the carrier of the other party is detected, the pause detector 19 no longer detects a pause due to this carrier, so the pause detector 19 is reset at the same time as detecting the carrier. Even in this case, when a pause is not detected (types 5 and 6 in the table above), there is a transmitted audio signal, and there is a mismatch in pause detection, so the other party does not detect a pause due to communication between modems. A special command is sent to correct the discrepancy, and the contacts of the changeover switches 4 and 7 are connected to the a side. Also, since carrier sound may be mixed in until the other party's carrier is detected, the audio signal delay circuit 8 delays the sound until the carrier is detected to prevent this carrier sound from being mixed in. There is. Next, the time division multiplex control method of the present invention will be explained using FIGS. 1 and 2. If a pause or modem carrier from the other party is not detected (types 1 and 2 in the table above), the contacts of changeover switches 4 and 7 are connected to side a, and the audio signal from the telephone line is transferred to hybrid coil 5, audio The signal is outputted to the audio signal output terminal 2 via the signal delay circuit 8 and the hybrid coil 3. Further, the preset type variable amplifier 18 amplifies the received audio signal 32 before passing through the audio signal delay circuit, compensates for line loss, and outputs it to the pause detector 19. In addition, the transmission audio signal is transmitted to the audio input terminal 1.
From there, it passes through hybrid coil 3 and hybrid coil 5 and becomes an output at telephone line terminal 6. Note that this transmitted audio signal 21 also serves as an input to the pause detector 19. When the pause detector 19 detects a pause, that is, the output signal D of the pause detector 19 (or
When D') changes from d to e (or from d' to e'), if the amount of data accumulated in the transmission buffer memory is at least a certain threshold (type 4 in the table above), the control unit 20 sends a control signal 27 output (C or C′),
Switch the contacts of changeover switches 4 and 7 from a to b. In addition, the modem is driven by the modem control signal 29, and a special command f (or f') is issued to synchronize data communication from the modem.
A command sequence is generated, and this command sequence is outputted to the telephone line terminal 6 via the hybrid coil 13 and the hybrid coil 5, and transmitted to the other party. Here, the special command string that is the response from the other side
When f' (or f) is detected (F is in the i state or F' is in the i' state), transmission of the image signal begins (g or g'). At this point, the pose detector 19
The only input is the transmitted audio signal, and only pauses in the transmitted audio signal 21 are detected. Next, for example, pose detector 1 of the B-side terminal
Detect that 9 is not a pose (i.e.
D' changes from e' to d'), a command sequence h' to stop the transmission of the image signal is sent, and a command h, which is a response to the command sequence from the A side, is received (F' changes from e' to d').
j') then stops h', and the carrier from the B side stops (G' changes from k' to l'), the control unit 2
0 switches the contacts of changeover switches 4 and 7 to the a side and shifts to voice communication. Also, when side A receives a special command h' from side B (F becomes j), it outputs command h as a response, and when command h' on side B stops, it stops command h, and When the carrier on the side stops (G changes from k to l), the contacts of changeover switches 4 and 7 are connected to side a, and voice communication is started. Note that even if a pause is detected, if the amount of data accumulated in the transmission buffer memory is less than the threshold value (Table Type 3 above), the state remains unchanged (voice communication state). Next, the case where the carrier of the other party is detected will be explained using FIGS. 1 and 3. For example, the full-duplex modem 12 on side B detects the carrier from side A (i.e., G' is from l'
k'), the control section 20 switches the changeover switch 4
Contacts 7 and 7 are connected to side b, and communication using the modem begins. In this case, if the pose detector 19 detects a pose, the modem transmits the image signal. Here, when the pause detector 19 detects that there is no pause (that D' is in the state d'), it immediately transmits a termination command h' for mismatch correction through the modem, and receives a response from the A side. When a command h is detected, the command h' is stopped, and
Next, the carrier from the A side stopped (G′ changed from k′
l'), the contacts of changeover switches 4 and 7 are connected to side a, and voice communication is resumed. In addition, in the explanation of the present invention, if it is detected that the other party's carrier is not paused, the mismatch is immediately corrected through the modem, but in this case, the side that detected the carrier , immediately connect the contacts of changeover switches 4 and 7 to the b side, but do not correct the discrepancy through the modem, keep the state as it is, and switch changeover switch 4 as soon as it no longer detects the other party's carrier. Contacts 4 and 7 are connected to the a side to return to voice communication, and on the other hand, if the side that sent the carrier does not detect a response from the other party after a certain period of time, changeover switches 4 and 7 are connected to side a.
It is also possible to connect the contact point to the a side and return to voice communication. As explained above, pause periods in voice conversation are detected, image signals such as handwritten characters and figures are transmitted during these pause periods, and simultaneous transmission is performed by time division multiplexing, so the voice signal bandwidth is This has the advantage that sound quality does not deteriorate due to reduction. In addition, since the received audio signal input to the pause detector is amplified using a preset type variable amplifier, it has the advantage of preventing discrepancies in pause detection due to line loss. Even in such a case, by performing carrier detection, the discrepancy in pause detection can be detected and the discrepancy can be corrected through the modem. Therefore, there is an advantage that mismatches in pause detection rarely occur, audio cut-offs caused by this can be reduced, and there is very little deterioration in audio quality. Furthermore, since it uses an audio signal delay circuit,
This has the advantage that carrier sound is not mixed in until the carrier is detected.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of FIG. 1. 1... Audio signal input terminal, 2... Audio signal output terminal, 3... Hybrid coil, 4... Changeover switch, 5... Hybrid coil, 6... Telephone line terminal, 7... Changeover switch, 8... Audio signal delay circuit, 9... Image signal input terminal for handwritten characters and figures, etc., 10... Encoder, 11... Transmission side buffer memory, 12... Full duplex modem, 13
. . . Hybrid coil, 14 . . . Reception side buffer memory, 15 .
Pause detector, 20...control unit, 21...transmitted audio signal, 22...received audio signal after amplification, 23...
... Pause detector output, 24 ... Modem carrier detection output, 25 ... Data storage amount detection result output of transmission buffer memory, 26 ... Control signal from the other party through modem-to-modem communication, 27 ... Control signal, 2
8...Pause detector reset control signal, 29...
Modem control signal, 30... Received signal, 31... Modem carrier level detector output, 32... Received audio signal, 33... Modem output signal, C and C'...
...Controller output signals 27, D and D'...Pause detector output signals 23, E and E'...Modem output signals 33, F and F'...Decoder output signals 2
6, G and G'...Carrier detection output 24, a
and a'...control signal state that connects changeover switches 4 and 7 to side a, b and b'...control signal state that connects changeover switches 4 and 7 to side b, d and d'...detects pause. Pause detector output when not in use, e and e'... Pause detector output when paused, f and f'... Special command for synchronizing between modems, g and g'...
Image signal, h and h'...Special command to end image signal communication, i and i'...state where commands g and g' are detected, j and j'...command h and h' are detected state, k and k′...
Carrier detection state, l and l'...state where carrier is not detected.

Claims (1)

[Claims] 1. Means for detecting a pause period of a voice conversation and a modem for detecting a modem carrier from the other party in a simultaneous transmission method of voice and information in other forms (hereinafter simply referred to as other information) a carrier detection means, a data storage amount detection means of the transmission buffer memory, a means for switching between transmitting the audio signal and transmitting other information according to the detection results of the three types of detection means; means for adjusting the amplification degree of the received signal according to the absolute level of the modem carrier, and in the above three types of detection results, when a pause period is detected and the amount of data accumulated in the transmission buffer memory is above a certain threshold value, transmits other information, and if it detects a carrier and does not detect a pause period, it transmits information for temporarily correcting discrepancies and then transmits only the audio signal,
A method for simultaneously transmitting voice and other forms of information, characterized in that in other cases only the voice signal is transmitted, and voice and other information are time-division multiplexed and transmitted simultaneously. 2. A simultaneous transmission system for audio and information in other forms as claimed in claim 1, characterized in that means is provided for delaying the audio signal in order to prevent carrier sound from being mixed in.