JPS5842667B2 - Various data transmission methods for data transmission systems - Google Patents

Description

Detailed Description of the Invention The present invention provides a method in which data on one line is used by a network control device and a modem, respectively, and the output data of the modem is transmitted using a telephone line connected to the network control device. In a transmission system, that is, a system in which the signal formats for transmission and reception by the receiving device are different, such as bit synchronization and start-stop synchronization, the signal format can be changed without the transmitting device sending out a switching signal that foretells the switching of the signal format to be sent. This invention relates to various data transmission methods of a data transmission system that can be switched on the receiving device side.

In systems where multiple terminal devices are installed in areas remote from the area where the center is installed, a subcenter is usually set up at one location in the area where the terminal is located, and a dedicated Telephone lines are also used between subcenters and terminal devices.

Figure 1 is a diagram showing the configuration of such a conventional system.
U is the center, MOD1 to MOD5 are the modulation and demodulation devices (hereinafter referred to as
(referred to as a modem), NCU is a network control device, LF is a converter, DTEO to DTEn are terminals, Ll is a dedicated line, Ll
is a telephone line.

The procedure by which the center CPU calls a specific terminal DTEO will be described below.

First step: First, the center CPU is connected to the network control unit NCU.
A calling signal for activating the modem MOD2 is output to the modem MOD2 via the interface signal line.

In response, the modem MOD2 turns on the bit corresponding to the call signal in a register (not shown) consisting of bits corresponding to each of the interface signal lines on the network control unit NCU side, and the contents of this register (hereinafter referred to as interface data) is bit-serially modulated and assigned to a predetermined channel of the dedicated line L1, and the modem MO
Send to D2'.

The modem MOD 2' transfers the interface data of the predetermined channel to the network control unit NCU via the interface signal line.

In this case, since the paging signal line within the interface signal line is turned on, the paging signal issued by the center CPU is notified to the network control unit NCU.

Second step: In accordance with this notification, the network control unit NCU puts the exchange LF into a so-called hook-on state, extracts and determines the transmission register sound of the exchange LF continuously for a predetermined period of time, for example, about 2 to 3 seconds, and determines whether the exchange LF is connected to the exchange LF. Detect things.

In response, the network fftlJffllll device NCU turns on the signal line requesting the telephone number among the interface signal lines.

In this on state, a plurality of bits equal to the number of interface signal lines constitute one frame in the modem MOD2', and the modulated information is allocated and transmitted to other channels of the dedicated line L1.

Modem MOD2 demodulates this, parallelizes this one frame, assigns it to each interface signal line, and sends it to the center C.
Notify the PU that a phone number has been requested.

Third step: In response, the center CPU outputs the first digit of the telephone number to one interface signal line, and further indicates that number information is being sent, which is provided in parallel with the interface signal line that notifies the number. Turn on the strobe signal line and notify modem MOD2.

The modem MOD2 turns on/on the bit corresponding to the telephone number output to the interface signal line, and notifies the network control unit NCU via the modem MOD2'.

When the network control unit NCU receives this one-digit number, it stores it in an internal register (not shown), turns off the number request signal line, and notifies the center CPU of this.

As a result, the center CPU turns off the strobe signal line.

The network control unit NCU detects that the strobe line is turned off, and turns on the above-mentioned number information request signal line again in order to request the next digit of the telephone number.

Thereafter, the same process is repeated, and the network control unit NCU stores in the internal register up to the last digit notified from the center CPU.

Fourth step: At this point, the network control unit NCU sends a dial pulse or a button signal to the exchange LF that has already been connected in the second step.

In response to this, the exchange LF connects the network control unit NCU and the modem MOD connected to the corresponding station number via the telephone line L2.
4 Connect with.

The network control unit NCU determines the connection timing, for example,
Detects the polarity reversal of the telephone line and connects the modem M to the center CPU.
Notifies completion of connection with OD4.

Fifth step: Upon receiving the connection completion notification, the center CP
U uses the modem N0DI to modulate the data to be transmitted in a bit synchronized manner onto a channel different from the predetermined channel of the dedicated circuit L1, and transmits the data to a channel different from the predetermined channel of the dedicated circuit L1, the modem MOD3, the network control unit NCU, and the telephone line L2. , data is exchanged with the terminal DTE O via the modem MOD4.

However, in these conventional systems, ■ When controlling the network control equipment, it must be controlled using the so-called start-stop synchronization method of shakehand communication, so the modem also uses the normal bit synchronization method for transmitting data. Modem (compatible with modem MODI) and modem using start-stop synchronization method for transmitting control data of network control equipment (compatible with modem MOD2)
and each must be performed via separate channels or using different time slots in one transmission frame.

An object of the present invention is to eliminate these conventional disadvantages (in order to efficiently provide a multi-type data transmission method for a data transmission system that can control connection only with a predetermined channel of one transmission line and also allows normal data transmission). The object of the present invention is to provide a data transmission system with a wide variety of data transmission methods, which also provides reliable signal format switching control.

In order to achieve the above object, the present invention includes a switch means for switching the transmission/reception signal format and transmitting the signal at a point corresponding to the entrance/exit to the data transmission line of the transmitting device and the receiving device, and a switch means for transmitting the signal in a predetermined signal format on the receiving side. A means for detecting a certain event is provided, and normally a switching signal is sent from the transmitting side, but the signal form can also be switched by this detecting means.

Hereinafter, the present invention will be explained in detail based on examples.

2 and 3 are system block diagrams of an embodiment of the present invention. In the figures, the same components as those used in FIG. 1 are indicated by the same symbols.
is an adapter, and MOD3' is a modem.

Here, the adapter ADP 1 performs parallel-to-serial conversion on the interface signal line IFI input in parallel from the center CPU to convert it into data of a predetermined bit, and also converts it into data of a predetermined bit. The adapter ADP2, which is connected to the modem MODI and unifies the interface control method with the modem MODI, serially receives demodulated data from the modem MOD3, creates data corresponding to the interface signal line IF3 for the network control unit NCU, and also If the serially received data from MOD3 is not control data for the network control unit NCU, modem M
This is supplied as data to OD 3'.

The operation based on the configuration shown in FIG. 2 will be explained below.

In the first step mentioned above, the network from the center CPU! When the paging signal of the Im device NCU is demodulated by the modem MOD3, the adapter ADP2 turns on the paging signal line in the interface signal line IFa to the network control device NCU.

At the same time, the adapter ADP2 sends to the modem MOD3 interface data in which the bit corresponding to the telephone number request signal line is turned on.

That is, before the network control unit NCU turns on the telephone number request signal line, the adapter ADP2 connects to the center CP.
This is to notify U of a telephone number request signal.

In the same manner as in the third step described above, the center CPU performs the following steps.
Send the telephone number to adapter ADP 1 .

The adapter ADP1 notifies the adapter ADP2 of the information on the interface signal line F1 including the telephone number via the modulated modem MOD1 and modem MOD3.

The adapter ADP2 sends and receives a telephone number to and from the center CPU according to the procedure of the third step described above, and stores data including this telephone number in the memory or register provided in the adapter ADPZ.

On the other hand, in the same manner as in the second step described above, the network control unit NCU turns on the corresponding signal line in the interface signal line IF3 with the telephone number information request signal.

The adapter ADP2 detects this on state, and the telephone number stored in the memory or register is stored in a register (not shown) of the network control unit NCU according to the interface procedure performed between the center CPU and the network control unit NCU in the third step described above. The network control unit NCU sends dial pulses to the exchange LF'.

The network control unit NCU sends a connection completion signal with the exchange LF to the adapter ADP2 via the interface signal line IF3.
When the adapter ADP2 notifies the modem M
The center CPU is notified via OD3, modem MOD I, adapter ADP1, and interface signal line IF1.

The center CPU thereby delivers the sending data to the modem MODI via the adapter ADP 1 in accordance with the normal output procedure of the interface signal line IFO for the modem.

The transferred data is modulated by the model MODI, allocated to the dedicated line L1, and transmitted.

The modem MOD3 receives this, demodulates the data, and supplies it as transmission data to the modem MOD3' via the adapter ADP2.

The modem MOD3' receives the carrier detection signal received from the modem MOD3 via the adapter ADP2 as a transmission request signal, and receives the received data signal of the modem MOD3 as a transmitted data signal.

For this reason, modem MOD 3' first
The carrier detection signal becomes an activation signal in accordance with the transmission request signal, modulates the reception data of the modem MOD3 which is input in pit synchronization, and sends it out to the telephone line via the network control unit NCU.

That is, from this point on, the center CPU uses the interface signal line IFO to transmit data to the terminal device DTE in an asynchronous manner.

FIG. 3 is a detailed block diagram of the adapter ADP2, in which M and D are modem MOD3 and modem MOD3, respectively.
The modulator and demodulator in 'T, SWR.

Product N is a switch, IRM, ORM, IRN, ORN are interface registers, MPU is a processor,
MEM is memory, OP is monitoring unit, CT is counter, OR
is an or gate.

Further, the same parts in FIGS. 1 and 2 are given the same symbols.

That is, when the demodulated data of the modem MOD3 is input to the adapter ADP2, it is input to the interface register IBM.

On the other hand, the modem MOD 3' is always gated by the switch SWR except during the above-mentioned normal data transmission period.

The received data input to the interface register IBM is read by the processor MPU and is first memo! Stored in JMEM.

The stored data is compared with the data read immediately before, and by determining the bit position where the change point exists,
Detect the type of received data.

For example, when reading data in which the bit in the position corresponding to the call signal has changed, the processor MPU determines this and stores the data in which the bit in the position corresponding to the telephone number request signal is in the ON state in a predetermined deposit in the memory MEM. read from the area,
Set in interface register ORM.

On the other hand, for the network control unit NCU, the processor MPU
Note the data whose bits have changed for the ring signal.
It is read from another predetermined area of JMEM and set in the interface register ORN.

The data including the telephone number request signal bit set in the interface register ORM is sent serially via the switch SwT to the modulation section M of the modem MOD3 according to a predetermined modem interface procedure.

Also, as the procedure progresses and a telephone number is sent from the center CPU and set in the interface register IRM, the processor MPU determines this and memorizes it! JIV
Store it in iEM.

Interface signal lines output from the network control unit NCU are input to each bit position of the interface register IRN.

In addition, the processor MPU has an interface register I.
A period other than the period of reading the BM, for example, a period after the time when all telephone numbers have been stored in the memory MEM, or
The interface signal line of the interface register IRN is read during a period when a predetermined bit is being stored in the interface register IBM.

When a telephone number is requested from the network control unit NCU, the processor MPU reads it from the interface register IRN, reads out the telephone number stored in the memory MEM one digit at a time as described above, and sets it in the interface register ORH. , and notify the network controller NCU.

Here, the procedure of the third step described above, that is, the center C
The adapter ADP
2 and the network control unit NCU.

When the network control unit NCU completes connection with the terminal side modem etc. via the exchange LF, it sets a connection completion signal in the interface register IRN.

Processor MPU uses this interface register IR
By reading and determining the data of N and setting it in the interface register ORM, the modem MOD3, and therefore the center CPU, is notified of the completion of the connection via the switch SwT.

The center CPU that received this connection completion is the main dem MOD.
3 demodulator, the interface register IRM
Since the bit position of the calling signal is turned off and the bit position indicating switching of the synchronization method is turned on, the processor MPU determines this and sets the switch separately to the receive data terminal of the modem MOD3', and therefore to the demodulator. and closes the switch SWR to connect the receiving data terminal of the modem MOD3, and thus the demodulating section's downstream side, to the transmitting data terminal of the modem MOD3, and therefore the modulating section M.

Further, at this time, the processor MPU connects the interface signal lines between the modem MOD3 and the modem MOD3' by a switch (not shown) so that the transmission and reception are reversed, and at the same time, in order to detect an asynchronous data pattern. The monitoring unit OP is also activated.

The monitoring unit OP constantly monitors whether a star bit, a stop bit, and, if necessary, a parity bit are present in a predetermined position of the data in the interface register IRM.

That is, the data for controlling the network control unit NCU is made up of a predetermined number of bits and is made up of one transmission frame.As mentioned above, a start bit is added to the beginning of the frame and a stop bit is added to the final position of the frame. It can be detected by its presence.

On the other hand, when the modem MOD3' is switched and connected, the data transmitted during that time is in the form of signals such as bit synchronization or frame synchronization, so the monitoring unit OP does not issue a detection output.

However, the transmitting side must avoid an asynchronous data pattern (i.e., a pattern with a start bit, stop bit, and parity bit within a predetermined number of bits) when transmitting data is bit-synchronous. Needless to say.

No line failure occurs, interface register IBM
When the switch signal to asynchronous synchronization sent from the center CPU is input to the processor MPU, the processor MPU determines this and restores the switch SWL and the switch SWR, and the network control unit NCU
The control mode shifts to the asynchronous data signal format.

However, due to line failure or noise, the center CP
If the switching signal sent from U is modified and input to the interface register IRM, the processor MPU cannot restore the switch 5wT1 and the switch W.

,. On the other hand, once the center CPU sends out the switching signal, it assumes that the receiving device has been switched from the modem MOD 3' to the network control unit NCU, and transmits data in an asynchronous manner according to the operations after the first step described above. do.

As a result, an asynchronous signal pattern is stored in the interface register IRM in the adapter ADP2 on the receiving side.

Here, when the monitoring unit OP continuously detects the asynchronous data pattern, it counts up the counter CT.

When the counter CT counts a predetermined number, it emits an output pulse t to reset itself, and also restores the switch quality and switch SWR via the OR gate OR.

This causes the data stored in the interface register ORM to be sent to the center side.

In addition, the center CPU and the modem MODI shown in Figure 2
Although the adapter ADP1 between the third
The center CPU is placed at the network control unit NCU and modem MOD3' position in the figure, and the modem MOD is placed at the modem MOD3 position.
It is sufficient to form a configuration in which I is arranged.

At this time, it goes without saying that each data in the interface registers IRN and ORH has a meaning opposite to that for the network control unit NCU.

Furthermore, in the above explanation, the case where the center CPU makes a call to the terminal was explained, but when calling the center from the terminal, the modem on the terminal side (MOD 4 in Fig. 1)
, MOD5) may be provided with a network control device and connected to the modem MOD3' located at the adapter ADP2, which is a sub-center.

As described above in detail, according to the present invention, the adapter A
Since DP1 and adapter ADP2 switch between data transmission using the shakehand method and data transmission using the start-stop synchronization method in one channel, the modem and line can be used in one time slot, and therefore the system This has the effect that the receiving side does not become large in size, and the receiving side can automatically switch its reception format even if a switching signal does not arrive due to line failure or noise.

[Brief explanation of the drawing]

FIG. 1 is a conventional system configuration diagram, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is a detailed diagram of the main part of FIG. ADP2 is an adapter, MODI to MOD5 are modems, NCU is a network control device, DTEO to DTEn are terminal devices, Ll and L2 are lines, IFO to IF4 are interfune signal lines, LF is a switch, and M is a modulation section of the modem. , D is a demodulating section of the modem; SWR is a switch, MPU is a processor, MEM is a memory, ORM, IRM, OPN, and IRN are interface registers, CT is a counter, and OP is a monitoring unit.

Claims (1)

[Claims] 1 has a data transmitting device, a predetermined number of data receiving devices, and a data transmission line, each of the data receiving devices receiving a predetermined signal format of data in different signal formats transmitted from the data transmitting device. In a data transmission system that receives data synchronized with a data transmitter, a switch means is provided on the data transmission line side of the data transmitter and the predetermined number of data receivers to switch and receive data in different signal formats. Further, a detecting means for detecting that the signal form of the data on the data transmission line is a predetermined signal form is provided on the side of the predetermined number of data receiving devices, and the predetermined signal is detected according to the detection output of the detecting means. A multi-type data transmission method for a data transmission system, characterized in that data from the data transmission line is supplied to a data receiving device corresponding to the format.