JPH0761168B2 - Multi-frequency signal transmission / reception method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-frequency signal transmission / reception protocol, and more particularly, accurately and quickly even when the state of a line for transmitting a signal is unstable and frequent interruptions occur. The present invention relates to a multi-frequency signal transmission / reception method suitable for transmitting information.

[Conventional technology]

FIG. 6 is a relay system diagram of the exchange system. The originating station 1 and the terminating station 2 are connected by an outgoing trunk 3 and an incoming trunk 4, and the outgoing trunk 3 is a multi-frequency signal (also called MFC signal).
The input trunk 4 is connected to the transmitter 5 and the MFC signal receiver 6 is connected thereto. Here, the line between the outgoing trunk 3 and the incoming trunk 4 is connected by wire or wirelessly. On the calling station 1 side, the MFC signal from the MFC signal transmitter 5 is transmitted on the line, while on the receiving station 2 side, the MFC signal from the line is received and identified by the MFC signal receiver 6. It is what

Next, referring to FIG. 7, the conventional technique, that is, the MFC recommended by CCITT
A signal transmission / reception sequence will be described. First, the signal F ₁ is transmitted from the transmitting station 1. This signal ₁ is received by the terminating station 2 after the transmission time t ₁ . As soon as the signal F ₁ arrives at the called station 2, the called station 2 sends an instruction to send the next signal F _{2 to} the called station 1.
The signal B ₁ to be sent to is sent. In originating station 1 disconnects the signal F ₁ recognizes the incoming signal B _1. The terminating station 2 takes a timing t ₂ to determine whether this signal F ₁ disconnection is an instantaneous disconnection or a signal disconnection, and disconnects the signal B ₁ after a time t ₂ . Source station 1 has the same time as destination station 2.
After t ₂ , it is considered that the signal is broken and the next sequence is started. Therefore, in the MFC signal transmission / reception sequence recommended by CCITT, the longer the momentary interruption time is, the larger the value of the timing t ₂ needs to be, which causes a problem that the transmission / reception of the multi-frequency signal becomes slow. Further, if the momentary interruption continues for a time t ₂ or more, the signal sequence progresses to the next, so there is a problem that the signal after the momentary interruption is regarded as the signal of the next sequence and is erroneously recognized.

As a conventional malfunction prevention method of a multi-frequency signal receiver due to instantaneous interruption of a multi-frequency signal, a guard timer function is provided in the receiver as described in, for example, Japanese Patent Laid-Open No. 58-188989, and a multi-frequency signal is provided. There is a technology that prevents the multi-frequency signal from being recognized as a stop if the signal is stopped for a short time even if the stop.

By the way, in the Compeldo system, as shown in FIG. 7, the signal transmission / reception sequence can be carried out while confirming the appearance and disappearance of the signal from the other party on both the sending side and the receiving side of the multi-frequency signal. Therefore, for example, if a signal interruption occurs during transmission and reception of a forward signal from a transmitting station and a backward signal from a receiving station in the telephone network by the Compeldo method, the signal receiving side continuously receives the same signal. It will be. FIG. 8 shows the case where the instantaneous guard is performed by the conventional guard timing method. According to this, if the signal appears again during the guard timing, it is not recognized as the signal disconnection, and the disconnection occurs only at the time-out. By being recognized, erroneous transmission / reception of signals due to momentary interruption is prevented.

[Problems to be solved by the invention]

In the above-mentioned conventional technique, the signal disconnection is determined by the timing. Therefore, when the momentary disconnection time of the line becomes long, it is necessary to set the timing longer accordingly. Therefore, there still remains a problem that the signal transmission / reception speed becomes slow. In addition, when a signal is interrupted for a certain period of time or more, there remains a problem that the signal after the interrupt is erroneously recognized as another signal.

An object of the present invention is to provide a multi-frequency signal transmission / reception method which enables high-speed transmission / reception of multi-frequency signals without erroneous recognition of signals even when the line state is unstable and the interruption time is long. It is in.

[Means for solving problems]

The above-mentioned object is based on the multi-frequency signal indicating the information type to be transmitted next from the receiving station every time the multi-frequency signal from the transmitting station is received and identified by the receiving station. This is a multi-frequency signal transmission / reception method by the Compeldo method, in which a multi-frequency signal according to the information type is sent out. Wait until the multi-frequency signal to be transmitted next is identified as different from the multi-frequency signal being transmitted, and promptly notify the other party that the multi-frequency signal to be transmitted next is different from the multi-frequency signal already transmitted immediately before. On the assumption that the multi-frequency signal F of the same content is repeatedly transmitted N times (N: an integer of 2 or more) times continuously from the transmitting station, Multi-frequency signal to be transmitted evenly However, the multi-frequency signal is clearly distinguishable from other multi-frequency signals in terms of frequency, and is replaced with a repeat signal that is created in advance to mean the repeated transmission of the same multi-frequency signal. On the other hand, while the multi-frequency signal indicating the information type to be sent out at an even number and to be sent out next is sent from the receiving station as a state in which it is replaced with the repeat signal. This is achieved by transmitting and receiving the multi-frequency signal between the transmitting station and the receiving station so that the multi-frequency signal indicating the information type to be transmitted is transmitted.

[Work]

Since the end of the signal transmission / reception sequence is determined not by the disconnection of the signal but by switching to the signal of another frequency, it is not necessary to take the timing due to the disconnection of the signal, and the signal can be transmitted / received at high speed by this timing. Also, the sender,
When transmitting a signal from each receiving side, if the signal to be transmitted is always switched to a signal having a frequency component different from the previously transmitted signal, erroneous recognition due to a momentary interruption of the signal will be eliminated.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram showing a signal transmission / reception sequence according to an embodiment of the present invention. The transmitting station 1 sends out the signal ₁ as in FIG. 7, and the signal F ₁ is transmitted to the receiving station after the transmission time t _1. Arriving at 2. After the arrival of the signal F ₁ , the terminating station 2 sends out a signal B ₁ prompting the next signal F ₂ from the originating station 1. Up to this point, the process is the same as in FIG. 7. Next, the transmitting station 1 sends out the next signal F _{2 when} it recognizes the arrival of the signal B ₁ . When recognizing that the signal has changed from F ₁ to F ₂ from the change in the frequency component, the terminating station 2 sends out the signal B ₂ in order to prompt the sending of the next signal F ₃ . The signal sequence proceeds as described above. Finally, as in FIG. 7, the transmitting station 1 determines the signal disconnection at the timing t ₂ and ends the signal transmission / reception sequence. According to the multi-frequency signal transmission / reception method as described above, the signal disconnection can be determined only when the last signal is disconnected, and the transmission / reception time is shortened by not having to take timings individually. Assuming that signals of n digits are exchanged, it can be seen from FIGS. 7 and 1 that the time required for transmitting and receiving a multi-frequency signal in the conventional method and the present method is the conventional method n × (3t ₁ + 2t ₂ ) this method n × 2t ₁ + 2t ₂ , which means that compared to the conventional method, the time {t ₁
It can be shortened by n + 2t ₂ (n-1)}. Further, by detecting the change in the signal frequency, the next signal sequence is advanced, so that the erroneous recognition due to the instantaneous interruption of the signal can be avoided. For example, in FIG. 1, the signal F ₁ has a short interruption.
Assuming that the signal F ₁ is received twice, the receiving station 2 receives the signal F ₁ twice. However, according to the method of the present invention, as long as the frequency of the received signal does not change, Since it is recognized as the same signal, even if the signal from the transmitting station 1 is interrupted for one or more times, the receiving station 2 can easily avoid erroneous recognition of the signal. I will get it.

As described above, in the present invention, the sequence is advanced to the next signal transmission / reception sequence for the first time by detecting the change in the signal frequency.
The same signal cannot be continuously transmitted from the transmitting station 1 over two digits or more. For example, as shown in FIG. 2, assuming that a signal F _{i of the} same frequency is transmitted from the transmitting station 1 three times, the receiving station 2 first receives the signal F _i and then receives the signal F _i. Since it is recognized that the frequencies of the received signals F _i are the same, the receiving station 2 cannot receive the signals F _{i of the} second and subsequent digits. More specifically, assuming that the three-digit number “222” is continuously transmitted from the transmitting station 1, the signal F _i means the number “2”, and the signal B _j is , "Send the next digit", it is sent as shown in FIG.
The signal F _i of the first digit and the signal F _i of the first digit received immediately before
Since there is no change in the frequency between and, the number "2" after the second digit cannot be received.

In order to avoid the above inconvenience, a repeat signal is newly created as a signal that can be clearly distinguished in frequency from other signals and that means repetition of the same signal. As shown in FIG.
From the above, the repeat signal and the signal F _i are alternately transmitted, while the destination station 2 may alternately transmit the signal B _j and the repeat signal. Thus, while the repeat signal is the signal F _i , the signal B _j
In the case of transmission between the source station 1 and the destination station 2, it is possible to prevent the source station 1 and the destination station 2 from continuously receiving signals of the same frequency. It can be transmitted and received continuously over a digit or more. Here, more specifically, assuming that the number “222”, that is, the number “2” is continuously transmitted from the transmitting station 1 three times, first, the signal F _i is the first digit. After being unilaterally transmitted from the originating station 1 to the terminating station 2 as meaning the numeral "2", the originating station 1 responds to the signal F _i in response to the signal B _j from the terminating station 2. A repeat signal is sent instead,
The receiving station 2 receives and identifies that it is a repeat signal, and also identifies that the second digit received digit is the same as the immediately preceding received digit (first digit digit), that is, "2". I will get it. After that, a signal different from the signal B _j transmitted immediately before must be transmitted from the terminating station 2 to mean “transmit the next digit”. Therefore, the repeat signal may be transmitted as a signal meaning "transmit the next digit". This repeat signal is received and identified by the transmitting station 1 as being different from the signal B _j received immediately before, and the transmitting station 1 sends the third digit "2". When transmitting the third digit "2", a signal different from the repeat signal transmitted immediately before, that is, the original signal F
It should be sent by _i . The receiving station 2 can receive the number "2" as the third digit by receiving and identifying the signal F _i as different from the repeat signal received immediately before. afterwards,
It is necessary for the receiving station 2 to send a signal meaning "send next digit", but the signal B _j is sent in place of the repeat signal sent immediately before. After all, the multi-frequency signal F of the same content from the transmitting station is N (N: 2
In the case where the multi-frequency signal F to be sent out at an even number is clearly distinguished in frequency from other multi-frequency signals, the multi-frequency signal F to be sent out is repeatedly transmitted from the transmitting station. In addition, the multi-frequency signal is sent as a replacement of the repeat signal created in advance to mean that the same multi-frequency signal is repeatedly sent. The multi-frequency signal indicating the type of information to be transmitted next is replaced with the repeat signal so that the multi-frequency signal indicating the type of information to be transmitted next is transmitted. It suffices if the multi-frequency signal is transmitted and received between the transmitting station and the receiving station. This makes it possible to avoid the progress of the sequence and erroneous signal recognition.

Next, how the MFC transceiver detects a momentary interruption when the above-described MFC signal transmission / reception sequence is performed will be described.

First, the control logic and instantaneous interruption detection logic of the MFC transmitter will be described with reference to FIG. After issuing the forward signal transmission request from the MFC transmitter, it transits to the backward signal reception monitoring state. When a backward signal is received in this monitoring state, whether or not the same signal is received is checked. When the first backward signal is received, the sequence is considered to be normal, the received backward signal is stored, the next forward signal transmission request is issued, and the state transits to the backward signal reception monitoring state again.

Here, if a momentary interruption occurs in the backward signal being received, the same backward signal will be received again at the time when the momentary interruption signal appears, but the original backward signal is again determined by the judgment whether the same signal is received or not. It is possible to return to the backward signal reception monitoring state. Therefore, it becomes possible to recognize only the correct signal while ignoring the instantaneous interruption of the signal.

At the end of the sequence, in the state where the disconnection request of the forward signal being sent is issued and the state is switched to the backward signal disconnection monitoring state, the guard timing is started when the backward signal is disconnected, and the sequence is ended when the time-out occurs. If the backward signal is received again during the guard timing, it means that the backward signal is interrupted. In this case, the state transits to the backward signal disconnection monitoring state again and waits for the backward signal to be disconnected.

Next, the control logic of the MFC receiver and the instantaneous interruption detection logic will be described with reference to FIG. If a forward signal is received while in the forward signal reception monitoring state, it is checked whether or not the same signal is received. At the first reception of the forward signal, the sequence is regarded as normal, the received forward signal is stored, then the backward signal transmission request is issued, and the state transits to the forward signal reception monitoring state again.

If a momentary interruption occurs in the forward signal being received in this monitoring state, the same forward signal will be received again at the moment when the momentary interruption signal appears, and the momentary interruption is ignored by the judgment logic whether the same signal is received. It becomes possible to do.

At the end of the sequence, after the transition to the forward signal disconnection monitoring state, the transition to the forward signal disconnection monitoring state is made, and when the forward signal is disconnected, the guard timing is started. If the forward signal is received during the guard timing, it means that the forward signal has a momentary interruption, so the state transits to the forward signal disconnection monitoring state again and waits for the disconnection of the forward signal. If no forward signal is received during the guard timing, a timeout occurs, a backward signal disconnection request being sent is issued, and the sequence ends.

〔The invention's effect〕

According to the present invention, since it is possible to proceed to the next signal sequence without determining the disconnection of the signal, it is possible to transmit and receive the signal at a higher speed than in the past, and to prevent erroneous recognition of the signal.

[Brief description of drawings]

FIG. 1 is a signal transmission / reception sequence diagram according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams when the same signal is continuously transmitted, and FIG. 4 shows a control procedure of an MFC transmitter. Flow chart, FIG. 5 is a flow chart showing the control procedure of the MFC receiver, FIG. 6 is a relay system diagram of the switching system, and FIG.
FIG. 8 is a conventional signal transmission / reception sequence diagram, and FIG. 8 is a conventional guard timing system signal transmission / reception sequence diagram. 1 ... Originating station, 2 ... Receiving station, 3 ... Outgoing trunk, 4 ...
… Incoming trunk, 5 …… MFC transmitter, 6 …… MFC receiver.

Claims (1)

[Claims] 1. Each time the multi-frequency signal from the originating station is received and identified by the terminating station, the multi-frequency signal transmitted from the terminating station indicates the type of information to be transmitted next. A method of transmitting and receiving a multi-frequency signal according to the Compeldo method, in which a multi-frequency signal according to the information type is transmitted. Wait for the multi-frequency signal to be received and identified as different from the multi-frequency signal being received, and if the multi-frequency signal to be transmitted next is different from the multi-frequency signal already transmitted immediately before, On the assumption that the multi-frequency signal F with the same content is repeatedly and continuously transmitted N times (N: an integer of 2 or more), it is assumed that the multi-frequency signal is transmitted promptly. , An even-numbered multi-frequency signal to be transmitted However, the multi-frequency signal is clearly distinguishable from other multi-frequency signals in terms of frequency, and is replaced with a repeat signal that is created in advance to mean the repeated transmission of the same multi-frequency signal. On the other hand, while the multi-frequency signal indicating the information type to be sent out at an even number and to be sent out next is sent from the receiving station as a state in which it is replaced with the repeat signal. A multi-frequency signal transmitting / receiving method in which a multi-frequency signal indicating a type of information to be transmitted is transmitted so that the multi-frequency signal is transmitted / received between a transmitting station and a receiving station.