JPH10294777A - Modem - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modem using a wired line that secures the security of the wired line with a comparatively simple method. SOLUTION: A transmission system using a modem is provided constituted of a transmission modem 13 that has a function of sending a training signal only for a prescribed time at the start of transmission, a reception modem 15, and a modem setting circuit 14 that sets operating conditions of the transmission modem 13 and the reception modem 15 and interconnects an information collection device 100 and an information collected device. The system is also provided with a single-pulse generating means 11, that generates a 1st pulse whose pulse width T1 and a 2nd pulse whose pulse width T2 simultaneously with a trigger, caused when a reception level of the reception modem 15 transits from an alarming state to a normal state, and the 1st pulse is used to bring the transmission modem 13 to a transmission stop state for the time T1 and an alarm sent from the reception modem 15 again is masked by the 2nd pulse, depending on the transmission stop state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modem device using a wired line. A modem using a wired line has developed a modulation technique year by year, and has been able to transmit extremely large amounts of data.

[0002] As the transmission capacity increases, the characteristics of the wired line must often be equalized so as to maintain the quality. Along with this, in many cases, a function is provided that can equalize the characteristics of a wired line in a modem, and this line is equalized before connecting the wired line.

[0003] The present invention mainly relates to monitoring and control of a communication device, and relates to a case where a portion connected by a wire is transmitted to an extremely distant place continuously for 24 hours, with an extremely high transmission speed.

[0004]

2. Description of the Related Art FIG. 11 is a diagram showing an example of a transmission system using a modem device. In the figure, 100 is an information collection device, 101 and 102 are modems, and 103 is an information response device.

Hereinafter, the operation of FIG. 11 will be described. First, after power-on and before data transmission, the modem 101 sends a predetermined training signal to the modem 102.

Therefore, when the modem 102 detects that the input signal is a training signal, the modem 102 adjusts the equalization characteristics of an internal equalizer (not shown) so that erroneous reproduced data can be obtained.

The above-mentioned line equalization is also performed by the modem 101, and the training signal at this time is transmitted from the modem 102 to the modem 101. Then, the information collection device 100
Is the clock CL always sent from the modem 101
Using K, data synchronized with this clock (for example,
Polling request), and the modem 101
To send to.

The modem 101 receives input data, for example,
Converts to 4 series of data, internal 16QAM not shown
The modulator modulates the carrier in addition to the modulator, and transmits a 16QAM modulated wave to a wired line.

[0009] The modem 102 demodulates the received 16QAM modulated wave, performs inverse conversion to extract the original data, and sends it to the information responding device 103. Therefore, the information response device 103
Detects that the input data is a polling request, and sends, for example, the operating state data of the own device as a polling response to the wired line via the modem 102. At this time, the polling response is synchronized with the clock transmitted from the modem 102, as described above.

[0010] Thus, the information collecting apparatus 100 collects the operation state data of the information responding apparatus 103 via the modem 101. When data is transmitted by a modem, it is often the case that a parity bit is added to detect a transmission error while monitoring the error.

[0011]

Generally, in the case of a half-duplex modem, a transmitting modem that has received an RTS (Request To Send) transmits a training signal (tens to hundreds of milliseconds) before transmitting data. For example, a scrambled H signal is transmitted, and transmission data is transmitted after the reception side can correctly receive the data.

Therefore, if the RTS is operated properly, the reliability of the line can be maintained. However, the information collection device 100 and the information response device 103 are conventionally connected by a wire,
Since it is not configured to transmit data via a modem, it does not have a function of transmitting an RTS to the modems 101 and 102.

On the other hand, in the case of a synchronous transmission system using a serial transmission line, the transmission line formed by a modem must be seen as a wire from the viewpoint of the information collection device and the information response device. That is, since the data rate sent by the information collecting apparatus and the data rate received by the information responding apparatus must be the same, it is not possible to monitor for errors by adding additional bits.

As a method of solving this, a gap is formed in the data stream by increasing the transmission speed of the modem communication path, and an additional bit is inserted into the gap or a gap is created by compressing the data itself, and the gap is formed at the same speed. However, the circuit configuration is complicated and it is difficult to reduce the cost.

An object of the present invention is to provide a modem device which can secure the reliability of a wired line by a relatively simple method.

[0016]

A first aspect of the present invention is a receiving module.
Check that the reception level of dem has shifted from the alarm state to the normal state.
With the pulse width T₁The first pulse of
Loose width T_Two(T_Two> T ₁) And simultaneously emit the second pulse
A means for generating a single pulse is provided.

Then, the transmitting modem is set to T ₁ by the first pulse.
Although the transmission is stopped only for a certain time, the alarm transmitted by the receiving modem is masked again by the second pulse according to the transmission stop state.

With such a configuration, when a signal without a response is received, or when a disconnection of an incoming call is detected, RT
Training is performed when recovery of incoming call disconnection is detected by operating S, and the line is recovered.

According to a second aspect of the present invention, the transmitting side and the receiving side are provided with the single pulse generating means according to the first aspect and the flag detecting means for detecting the end flag of the protocol from the input data.
Then, as a trigger flag detection output from the transmitting side flag detecting means, a first pulse sender single pulse generating means is transmitted, as well as the transmission stop state transmitting modem T ₁ times by the receiving flag detection means Triggered by the flag detection output from, the second pulse transmitted by the receiving-side single-pulse generating means masks again the alarm transmitted by the receiving modem.

With such a configuration, for example,
HDLC end flag is detected, and R
By operating the TS, the training is always performed again after the data transmission is completed.

A third of the present invention, a counter for counting the number of no response signal, providing a timer T ₀ hours. Then, when the counter counts the no-response signal more than the set number of times within the time T ₀ , the modem setting circuit causes the modem setting circuit to initialize again.

With this configuration, the modem is restarted when no response is detected more than a certain number of times within a certain period. According to a fourth aspect of the present invention, there is provided a transmission modem connected to both the working line and the protection line, a protection reception modem, and a working priority selection means for preferentially selecting the working reception modem.

The single-pulse generating means causes the transmitting modem to stop transmitting for the time T ₁ with the first pulse transmitted by triggering that the receiving level of the active receiving modem has shifted from the alarm state to the normal state. I tried to do.

In the case of a duplex wired line, such a configuration allows the current receiving modem to terminate the incoming call.
It switches to the standby side instantly and R
Since the TS is operated, the standby side normally receives the data until the TS is restored.

Then, by the RTS operation at the time of recovery, both the working and the spare are trained. According to a fifth aspect of the present invention, the current priority selecting means and the means for confirming the end of the second pulse to the single pulse generating means and notifying the current priority selecting means are provided.

When the working priority selecting means detects that the receiving level of the working receiving modem has become lower than the set value, the working priority selecting means switches to the spare receiving modem. After receiving the message, the standby modem is switched to the working modem.

In the case of wired duplexing, by adopting such a configuration, when the active receiving modem is disconnected, it is instantly switched to the standby side and triggered by the recovery of the incoming disconnection to trigger the RT.
Since S is operated, the standby side normally receives data until recovery.

When the incoming call from the current receiving modem is restored, the single-pulse generating means confirms the end of the mask pulse and then permits the active priority selecting circuit to switch. That is, the present invention solves the above-mentioned problems by using R
The TS can be operated by the modem itself.

That is, as factors that prevent data from passing after training, it is conceivable that instantaneous disconnection of a line or mixing of large noise that causes loss of synchronization occurs. In the present invention, when an instantaneous interruption occurs in the line, an incoming call is interrupted, so when the restoration of the incoming call interruption is detected (at this time, the line returns to normal, but it is unknown whether data can pass or not). ), The RTS is momentarily released by the modem, and the detection of the termination of the call is masked for a certain period of time.

As described above, by automatically operating the RTS by the modem, the modem receiving unit can be trained when the line is momentarily interrupted, so that the reliable wired line is restored.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system configuration diagram to which the present invention is applied, FIG. 2 is a configuration diagram (part 1) of a first embodiment of the present invention, and FIG. FIG. 4 is an explanatory diagram of the operation of FIG. 3, and FIG. 5 is a configuration diagram (part 2) of the first embodiment of the present invention.

FIG. 6 is a block diagram of a second embodiment of the present invention, FIG. 7 is a block diagram of a third embodiment of the present invention, FIG. 8 is a block diagram of a fourth embodiment of the present invention, and FIG. Is a diagram showing an example of a working priority selection circuit, and FIG. 10 is a configuration diagram of a fifth embodiment of the present invention.

Hereinafter, FIGS. 1 to 10 will be described. In addition,
The same reference numerals indicate the same objects throughout the drawings. Also, the parts described in detail above will be described briefly, and the parts of the present invention will be described in detail.

First, a first embodiment of the present invention will be described with reference to FIGS. 1, 1 and 2 are modems, 50 is a collecting-side MPU unit, 51 is a display unit, and 52 and 62 in FIG.
Is a communication interface unit, 60 is a responding MPU unit, 11 in FIGS. 2 to 6 is a single pulse generation circuit, and 12 is an O
R circuit, 13 is a transmitting modem, 14 is a modem setting circuit, 1
5 is a receiving modem, 16 is an alarm (ALM) part, 111
Is a detection portion, 112 is an RST generation portion, 113 is a mask generation portion, 21 is an OR circuit, 22a and 22b are flag detection circuits, and 24 in FIGS.
5 is a timer, 26 and 27 are active priority selection circuits, 261,
262 is an alarm detection part, 263 is an inversion part, 264
Is a NOR portion, and 265 is a switch.

Now, referring to FIG.
Is a monitoring device that collects information on the responding side from the responding MPU unit 60 by polling. The communication interface units 52 and 62 are communication protocols (for example, HDLC)
Is composed of an LSI or the like that transmits and receives
The data is converted to the format specified by the LC and transmitted to the corresponding modems 1 and 2, and the input HDLC format data is inversely converted to the original data to convert the data into the MPU units 50 and 6.
Send to 0.

When the polling response is not received from the responding MPU section even though the polling request has been transmitted, the collecting-side MPU section 50 transmits a reset signal to the communication interface section 52 and the modem 1.

Thus, the communication interface unit 52
Resets an internal LSI (not shown) and the modem 1 transmits a training signal. In FIG. 2, when the power of the entire apparatus is turned on, the modem setting circuit 14 sets the transmission speed and the initial state of the equalizer for the transmission modem 13 and the reception modem 15; When the setting is completed, for example, the RTS at the “L” level is applied to the transmitting modem 13 via the OR circuit 12.

As a result, the transmission modem 13 enters a transmission enabled state from the fall of the RTS, and starts transmitting transmission data after transmitting the training signal transmitted from the information collecting apparatus 100. When an instantaneous interruption has occurred in the line, the ALM unit 16 detects that the incoming level of the receiving modem 15 has been interrupted.
Send to 1.

As shown in FIG. 3, the single pulse generating circuit 11 comprises a detecting portion 111, an RTS generating portion 112, and a mask generating portion 113. The operation of this circuit will be described with reference to FIG. That is, the detection part 111
When detecting that a trigger indicating the recovery of the disconnection detection signal from the M unit 16 has been input, the single pulse generation circuit 1
RTS generation part 112 and mask generation part 113 in FIG.
Are driven simultaneously.

[0040] Here, RTS generating portion 112 and the mask generation portion 113, for example, because they are composed of different monostable multivibrator time constant, for generating two kinds of pulses such as shown in FIG. _{4-1, 1} .

The width T ₁ of the pulse generated in the RTS generation part is shorter than the width T _{2 of} the pulse generated in the mask generation part. For example, the pulse shown in FIG. _4-1, during the pulse width used to release the RST (sending a stop), and can be transmitted in the area of the subsequent "L" level.

Now, when the RTS of the modem 1 is released, the incoming call is cut off at the modem 2 to be connected, and the modem 2 operates in the same manner as the modem 1.
Is also canceled (see (a), (b), and (c) of FIG. 4).

As a result, the incoming call of the modem 1 is interrupted again (see (d) of FIG. 4). here,
The other pulse of the single-pulse generation circuit is supplied to the single-pulse generation circuit 11 so that the RTS is not operated again when the modem 1 recovers from the second-time call termination. (See FIG. 4).
₁ ).

[0044] That is, by operating automatically RTS as described above, in the shaded area in FIG. _4-1, the line is restored it is possible to perform the modem receiver training after the line is instantaneously interrupted (see the hatched portion in FIG. _4-1).

In FIG. 5, the communication interface unit 52
Is configured by an LSI or the like that transmits and receives a communication protocol (for example, an HDLC protocol), and operates under the control of an MPU unit (not shown) on the collecting side.

For example, if a response is not received even though the collecting MPU unit (not shown) has transmitted a polling request several times to the responding MPU unit, as described above,
The collecting-side MPU sends out a signal for resetting the internal LSI to the communication interface 52.

Therefore, the reset signal is directly taken into the modem 1b as a no-response signal so that the modem can be trained even when there is no response. That is, as shown in FIG. 5, the OR of the no-response signal and the disconnection detection signal is input to the input side of the single pulse generation circuit 11.
An R circuit 21 is provided, and the output of the OR circuit 21 is applied to the single pulse generation circuit 11.

Thus, the RTS is operated when a no-response signal is received from the upper panel or when a disconnection is detected, and training can be performed when the transmission state is deteriorated. In FIG. 6, both the transmission side and the reception side have single pulse generation circuits 11a and 11b and flag detection circuits 22a and 22b.
b, for example, an end flag of the HDLC protocol is detected, and the RTS is operated after the data transmission is completed.

That is, the flag detection circuits 22a and 22b
Shift registers 221a and 221b for shifting data
, And compare 222a and 222b.
At 21b, the data is converted in parallel and added to the compare signals 222a and 222b.

Since the parallel-converted normal end flags are also added to the comparisons 222a and 222b, they are compared with the parallel-converted input end flags, and if they match, the result of the match is compared with the single pulse generation circuit 11a. , 11b.

As a result, the flag detection circuit 22a provided on the transmission side operates the RST when the transmission of the protocol end flag is completed, so that the training can be always performed after the data transmission is completed. Further, the reliability of the line is improved.

A flag detecting circuit 22 provided on the receiving side
In b, when the end flag is detected, a pulse for masking an alarm that causes an instantaneous interruption of the line is generated.
In FIG. 7, a no-response counter including a counter 24 and a timer 25 is provided.

[0053] Then, although counts the input count of no response signal using a counter 24, are the manner counter at the time of the time T ₀ has elapsed is reset. For example, if there are N or more non-response signals during the time T ₀ , the reset from the counter 24 is reset by the modem setting circuit 1.
4 is sent to the modem unit 1d.
Make the initial settings of.

According to this method, it is possible to avoid the abnormal operation of the modem. In FIG. 8, the ALM unit 1 is used in the case of wired duplication for extremely important monitoring information.
In this case, only the active alarm transmitted by the reference numeral 6 is used as a trigger.

In FIG. 8, a working priority selection circuit 26 is provided on the receiving side, and when the working line is disconnected, it is instantaneously switched to the protection line side, thereby making it possible to relieve a failure in the wired line. .

Here, FIG. 9 shows the ALM detection part 26.
1, 262, an inversion section 263, a NOR section 264, and a switch 265 are shown as an example of a working priority selection circuit. The operation of this circuit will be described below.

When the output of the ALM detection part is "L", there is no ALM, and when it is "H", ALM is generated. When the output of the NOR part is "L", the selector selects the working side. Suppose a. Working ALM detection part 261, spare ALM detection part 2
When both outputs of the ALM 62 are "L", the output of the active ALM detection part is inverted by the inversion part 263 to become "H", and NOR is output.
The output of the portion becomes "L", and the working side is selected. b. The output of the active ALM detection part is "H" and the spare ALM
When the output of the detection portion is "L", the output of the inversion portion becomes "L", the spare ALM detection portion becomes "L", and the NOR
The output of the portion becomes "H", and the spare side is selected. c. The output of the active ALM detection part is "L" and the spare ALM
When the output of the detection part is “H”, the output of the inversion part is “H”.
And the output of the NOR portion becomes "L", and the working side is selected.

Note that, when the protection line is disconnected and the working line is disconnected, the switching is not performed. As described above, when the working line is disconnected, it is instantaneously switched to the protection line side, thereby enabling a remedy in the event of a failure in the wired line.

In this case, since the operation of the RTS is triggered by the restoration of the incoming call disconnection, the operation is switched to the standby only while the active side is disconnected, and the communication is normally performed. In other words, in the case of a duplex wired line, when the active receiving modem is disconnected, the standby side is instantly switched to the standby side, and the RTS is operated with the recovery of the incoming call being a trigger. Is received.

Then, by the RTS operation after the recovery, both the working and the spare are trained. According to this method, the reliability of communication can be further improved. Similarly, the duplication can be applied to the first to third embodiments.

The configuration shown in FIG. 10 is for the case of extremely important monitoring information, in which the working / spare is completely equipped as a wired duplex structure (the spare also has an ALM unit 16b).
In FIG. 10, when the working side is disconnected, as described above, the working priority selection circuit 27 instantaneously switches to the protection side to secure communication, and when the working is restored, confirms that the training operation has been completed. And then switch back to working.

That is, in the case of a duplex wired line, when the active receiving modem is disconnected, the standby side is immediately switched to the standby side, and the standby side normally receives the signal until the termination is restored.
Then, the training is performed by the RTS operation triggered by the restoration of the incoming call disconnection, both the active and the standby.
After confirming the end of the mask pulse in the single pulse generation circuit and judging the end of the training, a permission to switch to the working priority selection circuit is output.

As a result, the reliability of communication can be further improved.

[0064]

As described in detail above, since the training can be carried out at all times or in an abnormal condition by a very simple method, the reliability of the wired line can be improved at relatively low cost.

In the case where a part connected by a wire is switched to remote information collection, synchronous serial communication is performed by a wire without changing the firmware of a higher-level device, software or hardware. Can be switched to a modem connection.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram to which the present invention is applied.

FIG. 2 is a configuration diagram (part 1) of a first embodiment of the present invention;

FIG. 3 is a configuration diagram of a main part of a single pulse generation circuit.

FIG. 4 is an operation explanatory diagram of FIG. 3;

FIG. 5 is a configuration diagram (part 2) of the first embodiment of the present invention;

FIG. 6 is a configuration diagram of a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 9 is an example of a working priority selection circuit.

FIG. 10 is a configuration diagram of a fifth embodiment of the present invention.

FIG. 11 is an example of a transmission system using a modem device.

[Explanation of symbols]

 1, 2 modem 11 single pulse generation circuit 12 OR circuit 13 transmission modem 14 modem setting circuit 15 reception modem 16 alarm (ALM) section 21 OR circuit 22 flag detection circuit 24 counter 25 timer 26, 27 current priority selection circuit 50, collection side MPU unit 51 display unit 52, 62 communication interface unit 60 responding MPU unit, 100 information collection device 101, 102 modem 103 information response device 111 detection circuit 112 RTS generation unit 113 mask generation unit 261 262 alarm detection unit 263 inversion unit 264 NOR part 265 switch

Claims (5)

[Claims] 1. A transmission modem having a function of transmitting a training signal for a predetermined time at least at the start of transmission,
A modem that has a receiving modem that sends an alarm when the reception level falls below a set value, and a modem setting circuit that sets the operating conditions of the transmitting modem and the receiving modem, and connects between the information collection device and the information collection device. In the apparatus, a _first pulse having a pulse width T _{1 and} a second pulse having a pulse width T ₂ (where T ₂ > T ₁ ) are triggered by the transition of the reception level of the reception modem from the alarm state to the normal state. A single pulse generating means for simultaneously generating two pulses is provided, and the transmission modem is set to a transmission stop state for the time T1 by the _first pulse. A modem device configured to mask with the second pulse. 2. A single-pulse generator according to claim 1, and a flag detector for detecting a protocol end flag from input data are provided on a transmission side and a reception side, and a flag detection output from the transmission-side flag detector is provided. as a trigger, the first pulse sender single pulse generating means is sent, the transmitting modem as well as the transmission stop state T ₁ times only as a trigger flag detection output from the receiving side flag detection means, receiving-side single pulse A modem device characterized in that the second pulse transmitted by the generating means masks the alarm transmitted by the receiving modem again. 3. A modem device according to the first aspect, a counter for counting the number of no response signal, provided the timer T ₀ hours, the counter is in T ₀ hours, no response or the set number A modem device, characterized in that when the signal is counted, the modem setting circuit causes the modem device to perform the initial setting again. 4. The modem device according to claim 1, wherein a transmitting modem connected to both the working line and the protection line, a protection receiving modem, and a working receiving modem are selected preferentially. The single-pulse generating means sets the transmitting modem to a transmission stop state for the time T1 with the _first pulse transmitted by triggering that the reception level of the current receiving modem has shifted from the alarm state to the normal state. A modem device, characterized in that the modem device is configured to: 5. The modem device according to claim 4, further comprising: a current priority selecting means, and a means for confirming the end of the second pulse to the single pulse generating means and notifying the current priority selecting means, When the priority selection means detects that the reception level of the active reception modem has become equal to or less than the set value, the priority selection means switches to the standby reception modem, but after receiving the end confirmation notification of the second pulse from the single pulse generation circuit, A modem device characterized in that it is configured to switch from a standby receiving modem to a working receiving modem.