JP2908181B2 - Communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system for performing data communication between a master station and a slave station through a telephone line, including a modem and a CPU connected between the station and the telephone line. The present invention relates to a communication device.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional communication system for performing data communication between a master station and a plurality of slave stations. In FIG. 2, reference numeral 1 denotes a master station including a personal computer or the like, and reference numeral 2 denotes a plurality of slave stations that communicate with the master station 1 and includes a sequencer, a controller and the like. Reference numeral 3 denotes an RS232C (or RS485) compliant interface connected between the master station 1 and the slave station 2, and reference numeral 4 denotes a communication line connecting the RS232C interface 3 and the slave station 2.

In the communication system configured as described above, the master station 1 transmits a control signal to the slave station 2 through the interface 3 and the communication line 4 to control each slave station 2 individually or as a whole. At the same time, various detection signals and request signals are transmitted from the slave stations 2 to the master station 1.

In this case, the master station 1 and the slave station 2 perform communication based on a communication protocol of a certain data format A.

In the communication system as described above, when the master station 1 and the slave station 2 are modified into a system for performing communication using a telephone line, a configuration as shown in FIG. 3 is obtained. In FIG. 3, communication devices 5 and 6 including a modem and a CPU are provided on the master station side and the slave station side, respectively, and these communication apparatuses 5 and 6 are connected via a telephone line 7.

FIG. 4 is a block diagram showing a configuration of a conventional communication device 5. In FIG. 4, reference numeral 8 denotes a transmitting and receiving unit for transmitting and receiving data to and from the master station 1, 9 a CPU for controlling communication such as automatic alerting, 10 a modem for modulating transmission data and demodulating received data, and 11 for a modem. A network control unit (NCU) that establishes and disconnects a line under the control of the CPU 9.

According to the above configuration, when a line is established by the NCU 11, the master station 1 sends out transmission data, and this transmission data is passed to the CPU 9 via the transmission / reception unit 8, and the CP 9
U9 sends to modem 10. Modem 10 modulates a carrier signal of a predetermined frequency with transmission data, and modulates the signal with NC.
It is sent from U11 to the telephone line 7.

The received data is added from the NCU 11 to the modem 10 and demodulated.
It is sent from the PU 9 to the master station 1 via the transmission / reception unit 8. The communication device 6 on the slave station side has the same configuration and operation as the communication device 5 described above.

As described above, since the communication devices 5 and 6 are provided with the CPU, the operators on the transmission side and the reception side can simultaneously operate the connection to the modem, respectively, as in the conventional communication devices that do not use the CPU. And the necessary data can be automatically sent from the slave station to the master station or from the master station to the slave station at the required time without the help of the operator. Also,
For example, when the parent station 1 of the transmission destination is busy from the child station 2,
The fact of the fact that the CPU of the communication device 6 on the slave station side can transmit the information to each slave station 2 allows the communication status to be communicated by the presence of the CPU.

When commercially available communication devices 5 and 6 are used, in the communication system shown in FIG. 3, it is necessary to perform communication in accordance with the communication protocol of the data format B of the CPU in the communication devices 5 and 6. is there.

[0011]

SUMMARY OF THE INVENTION Conventional communication devices 5, 6
Is configured as described above. Therefore, when the communication system of FIG. 2 is modified to a system as shown in FIG. 3 using a telephone line, the data format A used in the system of FIG.
Is required to be changed to the communication protocol in the data format B of the CPU 9 of the communication devices 5 and 6. For this purpose, it is necessary to change the programs of the master station 1 and each slave station 2, which requires a huge amount of work time and labor, and has a problem that the cost is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a communication device that can realize a communication system using a telephone line without changing a program. And

[0013]

SUMMARY OF THE INVENTION The communication device according to the present invention, after the establishment of the line, connect or through the CPU to communicate with connecting the transceiver and modem directly
Selection means for selecting whether communication is to be performed.

[0014]

The communication device according to the present invention establishes a line.
If the communication protocol originally used by the master station and the slave station does not match the communication protocol of the CPU in the communication device at the time of communication after the Can directly communicate with the master station and the slave station using the communication protocol originally used. Therefore, there is no need to change the program using a telephone line. Also, after establishing a line,
The additional control functions of the CPU, such as the automatic alarm function, are not impaired.

[0015]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, portions corresponding to those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 1, 1
Reference numerals 2 and 13 denote switches provided as selection means provided between the transmission / reception unit 8 and the modem 10, and each has a contact a connected to the transmission / reception unit 8 and the modem 10 and a contact b connected to the CPU 9. I have. Reference numeral 14 denotes a switching control unit that switches the switches 12 and 13 according to an instruction from the CPU 9. The communication device having the above configuration is used as the communication devices 5 and 6 in FIG.

Next, the operation will be described. If the communication protocol of the communication system of FIG. 2 does not match the communication protocol of the CPU 9, the switches 12, 1 are in a communication standby state.
3 is connected to the contact b. Master station 1 or slave station 2 in FIG.
When a line connection request is made via the transmission / reception unit 8 from
The CPU 9 receives this line connection request via the switch 12. Alternatively, when a telephone call is made through the telephone line 7, the CPU 9 receives the call via the NCU 11.

After controlling the NCU 11 to establish a line, the CPU 9 switches the switches 12, 13 to the contact a side. Thereby, the master station 1 and the slave station 2 in FIG. 3 can use the NCU 11 and the modem 1 without using the CPU 9 of the communication devices 5 and 6.
0, switches 12, 13 and the transmitting / receiving unit 8 for direct communication.

Accordingly, the communication protocol of the data format A in FIG. 2 can be used as the communication protocol in this case. That is, even if the system of FIG. 2 is modified to a system using the telephone line 7 as shown in FIG.
It is not necessary to change the program of each slave station 2.

The switches 12 and 13 are initially connected to the contact b
Is transmitted to the master station 1 or the slave station 2 automatically by the CPU 9 or informs the slave station 2 that the master station 1 is busy. Additional functions, such as an automatic alarm function, that the CPU 9 originally has are guaranteed. The switches 12 and 13 are returned to the contact a when the communication is completed or when the maximum line connection time elapses.

If the communication protocol of FIG. 2 matches the communication protocol of the CPU 9, the switch 1
Since the terminals 2 and 13 are kept connected to the contact b, they are used as the conventional communication device of FIG.

[0021]

According to the present invention, a line is established.
Later, a transceiver and modem and so constructed as to communicate or connect via or CPU communicates directly connected can be selected, for example, a communication system as in FIG. 2 using a telephone line Figure In the case where the communication system is modified into a communication system such as the one described in No. 3, it is not necessary to change the program only by changing the switch part of the communication device, and a communication system using a telephone line can be easily realized. C
The effect that the function of PU is also guaranteed can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a communication device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional communication system.

FIG. 3 is a block diagram showing a communication system using a telephone line to which the present invention can be applied.

FIG. 4 is a block diagram showing a conventional communication device.

[Explanation of symbols]

 Reference Signs List 8 transmission / reception unit 9 CPU 10 modem 11 network control unit 12, 13 switch (selection means)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-152596 (JP, A) JP-A-63-236442 (JP, A) JP-A-62-115956 (JP, A) JP-A-2- 134945 (JP, A) JP-A-63-95766 (JP, A) JP-A-5-130293 (JP, A) JP-A-4-154344 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) H04L 29/06 H04L 29/08

Claims (1)

(57) [Claims] A transmission / reception unit for transmitting / receiving data to / from an external device; a modem for modulating transmission data and demodulating received data; a network control unit for controlling establishment / disconnection of a line; And establish a line with a CPU having the above-mentioned network control unit and other control functions.
And a selection unit for selecting whether the transmission / reception unit and the modem are directly connected to perform communication after communication or via the CPU to perform communication .