JPH05336128A - Two-way data communication equipment - Google Patents

Abstract

PURPOSE:To control plural controlled equipments by using an RS232C interface. CONSTITUTION:Plural controlled equipments 32-1,32-2... generate a reply signal when a call signal allocated to itself is received. An RS232C interface 44 sends the call signal and receives the reply signal. The interface 44 is connected to communication cables 48-1,48-2... via an equipment control section 46 and the call signal is sent through the communication cables 48-1,48-2... while being branched to the controlled equipments 32-1,32-2... and the reply signal from the controlled equipments 32-1,32-2... is sent to the interface 44 through the cables via the device control section 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional data communication device, and more particularly to a device for bidirectional data communication according to the RS232C standard.

[0002]

2. Description of the Related Art Conventionally, a two-way data communication device is sometimes used to control a controlled device 4 from a control device 2 as shown in FIG. When the control data is transmitted to the controlled device 4 via the device-side RS232C interface 6, the communication cable 8, and the controlled device-side RS232C interface 10, the controlled device 4 causes the controlled device-side RS232C interface 10, the communication cable 8, and the control. Equipment side RS23
A reception notification is sent to the control device 2 via the 2C interface 6. In this way, the controlled device 4 is controlled according to the control data transmitted from the control device 2.

As described above, the RS232C standard presupposes a one-to-one bidirectional communication between two devices, so that one control device cannot control a plurality of devices. Therefore, when controlling a plurality of devices by one control device, as shown in FIG. 5, the controlled devices 12-1, 12- in the controlled devices 11-1, 11-2, ... 2 ... is controlled device side RS2
32C interface 28-1, 28-2 ..., Modem side RS232C interface 26-1, 26-
Are connected to the modems 24-1 and 24-2, respectively, and these modems 24-1, 24-2, ... Are connected to the transmission line 22. Is connected to the control device 14 via the modem side interface 18 and the control device side interface 16, and each controlled device 12-1,
Different identification numbers were previously assigned to 12-2.

When the control device 14 controls a specific controlled device, for example, the controlled device 12-1, an identification number assigned to the controlled device and control data for the controlled device 12-1 are serially transmitted. RS232C interface 16 on the control device side and RS2 on the modem side
It is supplied to the modem 20 via the 32C interface 18, modulated here, and supplied to the transmission line 22.

The modulated signal from the modem 20 is a modem 24-attached to each controlled device 12-1, 12-2, ...
Demodulated at 1, 24-2 ... RS2 on the modem side
32C interfaces 26-1, 26-2 ..., Controlled device side RS232C interfaces 28-1, 2
8-2 ... through controlled devices 12-1, 12-2.
・ ・ Supplied to

In each of the controlled devices 12-1, 12-2, ..., The received identification number is compared with the identification number assigned to the controlled device, and the controlled device is matched, in this case, the controlled device. 12-1 checks the received data, and if it can be normally received, a normal reception notification ACK, and if it is not normally received, an abnormal reception notification NAK, the controlled device side interface 28-1, the modem. It is supplied to the modem 24-1 via the side interface 26-1.

The modem 24-1 modulates this reception notification and supplies it to the modem 20 via the transmission line 22. The modem 20 demodulates this and supplies it to the control device 14 via the modem side interface 18 and the control device side interface 16. In addition, the controlled device 12-1 performs control according to the received control data when the device 12-1 can receive the data normally.

[0008]

As described above, the RS2
When attempting to control a plurality of controlled devices according to the 32C standard, an interface and a modem must be provided for each control device, resulting in a complicated configuration.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when a call signal assigned to itself is input, a plurality of response signals are generated in response to the input call signal. Controlled equipment is provided. While transmitting each call signal to each of these controlled devices,
In order to transmit the above response signals from each controlled device,
A communication cable is branched to each controlled device. An RS232C interface is provided so that RS232C standard call signals are transmitted to the communication cable and RS232C standard response signals from the controlled devices are received from the communication cable.

[0010]

According to the present invention, since the communication cable connected to the RS232C interface section is branched to each controlled device, the calling signal transmitted from the RS232C interface section is branched from the communication cable to Supplied to controlled equipment. Each controlled device transmits a response signal to the RS232C interface unit via the communication cable when the calling signal branched from the communication cable matches the calling signal assigned to itself. As a result, the interface unit transmits the response signal to the device that has transmitted the call signal, for example, the control device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This embodiment is a two-way system according to the present invention for remotely controlling a large number of satellite broadcasting receivers, satellite communication receivers, modulators, etc., which are provided at, for example, a headend of a joint hearing facility. As shown in FIG. 2, the communication device is used. The center device 31 and the head end 30 are connected to each other through a telephone line or the like at the joint hearing facility, and the head end 30
The controlled devices 32-1, 32-2, ... Which are, for example, the satellite broadcast receiver, the satellite communication receiver, the modulator, and the like are provided therein. These controlled devices 32-1 and 32-2
.. are assigned different device numbers and different identification numbers.

These controlled devices 32-1, 32-2 ...
Is controlled by a control signal from a control device 34 formed of, for example, a microcomputer in the center device 31. For example, as shown in FIG. 3, this control signal indicates STX indicating the start of transmission of the control signal, TYPE indicating the device number, ID indicating the identification number, what kind of data is sent, and the data length of these data. C for
W, each data DATA1, DATA2 ..., And serial data composed of ETX indicating the end of transmission of the control signal.

The control signal which is the serial data is transmitted to the control device side RS232C interface 36 and the modem side RS232C interface 3 in the center device 31.
It is supplied to the modem 40 via 8 and modulated, and then supplied to the modem 42 on the headend 30 side. This modem 4
2 demodulates the modulated signal, and through the RS232C interface 44 and the device control unit 46, the communication cable 48-
1, eg a pair of telephone lines. Communication cable 48
-1 is supplied to the controlled device 32-1 via the communication cable 48-1, and the controlled device 32-
1 to the controlled device 32-through the communication cable 48-2
2 is supplied. Hereinafter, it is similarly supplied to other controlled devices. That is, the control signal from the device control unit 46 is
While being transmitted through the communication cables 48-1, 48, 2, ...
It is input to ...

Each controlled device 32-1, 32-2 ...
Determines whether the TYPE and the ID of the input control signal match the device number and the identification number respectively assigned to itself, and if they match, the content of the received data is checked, and as a result of the check, If it can be received, the normal reception notification ACK is sent. If it is not received normally, the abnormal reception notification NAK is sent.
Send to. As a matter of course, the controlled device, which has the device number and the identification number coincident with each other and can be normally received, performs control according to the data of the transmitted control signal.

In order to control the plurality of controlled devices 32-1, 32-2 ... On the side of the head end 30 as described above, a modem or There is no need to provide an RS232C interface,
Control of the controlled devices 32-1, 32-2, ... Is performed by a single modem 42 and a single RS23 common to them.
This can be done using only the 2C interface 44.

In order to perform the control as described above, the device control section 46 and the controlled device 32-1 in the head end 30,
32-2 ... are configured as shown in FIG.
In the device control unit 46, the RS232C interface 4
The received data RXD input from the device 4, that is, the serial control signal transmitted from the control device 34 side in the center device 31 is input to the receiver / driver 50, and then supplied to the base of the transistor 53 via the resistors 51 and 52. To be done.

If a bit of the serial control signal is at H level, the transistor 53 becomes conductive and its collector becomes low potential. Since the collector of the transistor 53 is connected to the base of the transistor 54 via the resistors 55 and 56, a low potential is applied to the transistor 54 and the transistor 54 becomes non-conductive. Therefore, a high potential of + V, for example, 5 V, which is supplied to the collector of the transistor 54 via the resistor 57, is applied to the diode bridge of the controlled device 32-1 via the resistor 58 and one electric wire 48a of the communication cable 48. 60.

This high potential is supplied to the base of the transistor 64 via the diode 61 of the diode bridge 60 and the resistors 62 and 63, the transistor 64 becomes conductive, and the potential of the collector of the transistor 64 becomes low. Become. This low potential is supplied to the base of the transistor 67 via the resistors 65 and 66, and the transistor 67 becomes non-conductive. Therefore, the high potential of + V supplied to the collector of the transistor 67 is supplied to the CPU 70 via the resistor 68. That is, when the bit of the signal from the receiver / driver 59 is at the H level, the high potential, that is, the H level is supplied to the CPU 70 of the controlled device 32-1.

Also, if a bit of the control signal from the receiver / driver 50 is low, the transistor 5
3 becomes non-conductive, and the resistor 72 connected between the collector of the transistor 53 and the potential source of + V,
A high potential is supplied to the base of the transistor 54 through the resistors 55 and 56, the transistor 54 becomes conductive, and the collector has a low potential.

This low potential is supplied to the base of the transistor 64 through the resistor 58, one electric wire 48a of the communication cable 48, the diode bridge 60, and the resistors 62 and 63, and the transistor 64 becomes non-conductive. .. A high potential is supplied to the base of the transistor 67 via the resistor 74 and the resistors 65 and 66 connected between the collector of the transistor 64 and the + V potential source, the transistor 67 becomes conductive, and the CPU 70 Low potential is applied. That is, when the bit of the signal output from the receiver / driver 50 is at L level, the L level signal is also supplied to the CPU 70.

When the control signal is supplied to the CPU 70 in this manner, the CPU 70 determines whether the TYPE and the ID included in the control signal match the device number and the identification number assigned to itself. , If there is no match, there is no response. If they match, it is checked whether the control signal is normally received, and if it is normally received, ACK is output, and if it is not normally received, NAK is output.

This ACK or NAK is also a series of serial data, and when a certain bit of this data is at H level, this H level is supplied to the base of the transistor 80 via the resistors 76 and 78, Transistor 8
0 becomes conductive. As a result, this transistor 80
Has a low potential, and this low potential is
It is supplied to the transistor 86 via 2, 84. The collector of the transistor 86 has a resistor 57, one electric wire 48a, and a diode 61 of the diode bridge 60.
A high potential of + V is supplied through the transistor 86, but the transistor 86 becomes non-conductive.

As a result, the resistor 57, the resistors 88 and 90
The high potential + V is supplied to the base of the transistor 92 via the transistor 92, and the transistor 92 is turned on.
The collector of 2 has a low potential. This low potential is
It is supplied to the base of the transistor 98 via 4, 96, and the transistor 98 becomes non-conductive. Therefore, the high potential of + V supplied to the collector of the transistor 98 via the resistor 100, that is, the H level is supplied to the receiver / driver 50. That is, the CPU 70
Sets a certain bit of ACK or NAK to H level, the receiver / driver 50 is supplied with an H level signal.

When the CPU 70 sets a certain bit of ACK or NAK to the L level, the transistor 80 becomes non-conductive and + V is supplied to the collector of the transistor 80 from the high potential source of + V through the resistor 102.
Is supplied to the base of the transistor 86 via the resistors 82 and 84. At this time, the resistors 57 and 58, one wire of the communication cable 48, and the diode bridge 60.
Since a high potential of + V is supplied to the collector of the transistor 86 via the diode 61 of
6 conducts and its collector is at a low potential. as a result,
The potential at the connection point between the resistors 57 and 58 also becomes low, and the transistor 92 becomes non-conductive.

As a result, the transistor 92 becomes non-conductive, and the + V potential supplied to the collector from the + V high potential source through the resistor 104 is applied to the resistor 94,
The signal is supplied to the transistor 98 via 96, the transistor 98 becomes conductive, and a low potential signal, that is, an L level signal is supplied to the receiver / driver 50. Thus, the CPU
When 70 sets a certain bit of ACK or NAK to the L level, the L / level signal is also supplied to the receiver / driver 50. Then, the receiver / driver 50 transmits the ACK or NAK thus supplied to the transmission signal TX.
It is supplied to the RS232C interface 44 as D. As a result, it is finally supplied to the control device 34.

By the way, when the collector of the transistor 54 becomes high potential or low potential according to the signal from the receiver / driver 50, the collector of the transistor 98 also becomes low potential or high potential, and this potential change causes the receiver / driver 50 to change. Although provided and ultimately transmitted to controller 34, controller 34 is configured to ignore such signals. Further, 106 and 108 are constant voltage diodes, which are provided to make the voltage supplied to the collector of the transistor 86 constant. Further, if the control signal from the control device 34 is for itself, the CPU 70 of the non-control device 32-1 performs control according to the control signal.

The signal input to the controlled device 32-1 via the communication cable 48-1 is controlled by the controlled device 3-1.
It is supplied to the controlled device 32-2 through the communication cable 48-2 via the communication cable 2-1. This controlled device 32-2
Also, like the controlled device 32-1, four transistors,
It has a CPU, a diode bridge, and the like, and operates in the same manner as the controlled device 32-1. The signal supplied to the controlled device 32-2 is further supplied to the controlled device 32-3 (not shown) via the communication cable 48-3.
Similarly, it is supplied to other controlled devices. The other control devices are configured similarly to the controlled device 32-1.

In the controlled device 32-1, the diode bridge 60 is used in the communication cable 4
The connection of the electric wires 48a and 48b of No. 8 to the controlled device 32-1 is in the state shown in FIG. 1, and when the connection to the device control unit 46 is opposite to that of FIG. 1, that is, the electric wire 48b is the resistors 57 and 58. Even when connected to, the high potential is supplied to the diode 110 side of the diode bridge 60,
This is because a high potential is supplied to the base of the transistor 64 and the collector of the transistor 86 via the diode 110 to operate normally. That is, the communication cable 48-
This is because there is no need to consider the polarity when connecting 1, 48-2, ...

In the above embodiment, 5V is used as + V, but if a voltage higher than this is used, the noise resistance characteristic is improved. Further, in the above embodiment, the device control unit 4
6. Transistors are used for the controlled devices 32-1, 32-2, ..., However, if these are replaced with FETs, the data transmission speed can be increased. Further, in the above embodiment, the satellite broadcast receiver, the satellite communication receiver, the modulator and the like are used as the controlled devices, but it goes without saying that other devices can be used. Further, although the modems 40 and 42 are used in the above embodiment, these and the modem side RS232 are used.
The C interface 38 is omitted, and the control device side RS23
The 2C interface 36 may be directly connected to the 232 interface 44.

[0030]

As described above, according to the present invention, RS2
Since the RS232C standard control signal from the 32C interface is branched to each controlled device using a communication cable, RS232C is controlled for each controlled device.
It is not necessary to provide an interface or a modem, and one RS232C interface can control a plurality of controlled devices. Therefore, the structure can be simplified, the cost can be reduced, and the manufacturing is facilitated. Moreover, since the RS232C standard is used to connect each controlled device to the interface, it is possible to use a communication cable such as a telephone line, and a special dedicated cable is not required, which also reduces the cost. Can be made

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of an embodiment of a bidirectional communication device according to the present invention.

FIG. 2 is a block diagram of the same embodiment.

FIG. 3 is a diagram showing a structure of transmission data transmitted by a control device in the embodiment.

FIG. 4 is a block diagram of a bidirectional communication device using a conventional RS232C interface.

FIG. 5 is a block diagram of a bidirectional communication device between a plurality of devices using a conventional RS232C interface.

[Explanation of symbols]

 32-1 controlled device 32-2 controlled device 44 RS232C interface 48-1 communication cable 48-2 communication cable 48-3 communication cable

Claims (1)

[Claims] 1. When a call signal assigned to itself is input, a plurality of controlled devices that generate a response signal in response to the input call signal, and the above-mentioned call signals to the respective controlled devices are transmitted. To transmit the response signals from the controlled devices, the communication cables branched to the controlled devices and the RS232C standard calling signals are transmitted to the communication cables to control the controlled devices. A bidirectional data communication device comprising: an RS232C interface that receives the RS232C standard response signal from the device from the communication cable.