JPS60237745A - Connection system for communication control signal between processor and external device - Google Patents

Abstract

PURPOSE:To correct interface devices for modem connection mutually by using a cable which allow only one cable line to be connected to one terminal by adding terminals to a modem interface device newly and wiring them in the interface device. CONSTITUTION:Two terminals, i.e. CD' terminal 80 and RS' terminal 81 and two wires between a CD terminal 79 and CD' terminal 80, and as RS terminal 75 and an RS' terminal 81 are added. Then, the state of a data carrier detection signal inputted from the terminal 79 is outputted to the terminal 80 and the state of a request-to-send signal outputted from the terminal 75 is outputted from the terminal 81. When modem interface devices 7 are connected directly to each other by using this interface, the CD' terminal is connected to the CS terminal of the opposite-side modem interface device 7 to constitute a transmitting circuit for the device 7 and the RS' terminal is connected to the CS terminal of the interface device 4 to constitute a transmission permitting circuit at the side of the device 4.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention performs communication between a processing device and an external device each having a modem connection interface (international standard R8232C interface), or between processing devices. Background of the Invention FIG. 2 shows the original modem connection interface (R, 8232C interface) that is the premise of the present invention. A modem is a repeater used to communicate between devices via a communication line such as a telephone line.
On the transmitting side, the digital signal sent from the device is converted into FM
This device modulates the FM waves into digital signals and sends them out to the line, and on the receiving side demodulates the FM waves sent from the circuit into digital signals and sends them to the other device. For example, when transmitting data from the processing device 110 to the external device 120, the data (digital signal) sent by the CPU 1 to the cable 9 via the modem interface device 4 is modulated into FM waves by the modem 5 in order to be sent to the communication line. communication line 12
is sent to modem 6 via. The modem 6 demodulates the signal modulated into the FM wave again into a digital signal, and sends it to the modem interface device 7 and device 8 of the external device 120 via the cable IO. In this type of connection, since the telephone line 12 is interposed in the middle, the distance between the devices can be increased. Therefore, it is used for communication between a large electronic meter and a remote terminal device. Because of these advantages, the modem interface device 4 is often used as a standard external interface for personal computers, display devices, and the like. However, when communicating between devices over a short distance of several meters to several tens of meters, there is no advantage of being able to increase the communication distance between the modem and the communication line.
Since the signals sent by the interface device have sufficiently low noise, attenuation, and distortion over such a short distance, the modem/interface device is often directly connected to the modem without going through a communication line. In addition, in Figure 1, 2
is the main memory, 3 is the input/output device 11 and system bus 13
It is a controller for input/output devices installed between the
The CPU 1 and modem interface device 4 are connected via a system bus 13.

FIG. 3 shows a connection form for direct connection, but in this case, handling of the signal line 20 becomes a problem. FIG. 4 is a connection diagram of the signal line 9 between the Hamodem and the modem interface device.

The electrical characteristics and meaning of each signal line are defined by JIS-06361. The transmission data signal line 33 is a signal line for outputting data to be transmitted via the modem, and is a signal line for outputting data to be transmitted via the modem. It handles digital signals with a voltage of (denoted by e). The reception data signal line 34 is a signal line through which the modem transfers the data received from the communication line (referred to as a "line" according to JIS 0636) to the modem interface device of the receiving device, and the modem interface device of the device is The voltage at ω is treated as “0” and the voltage at θ is treated as “1” as a digital quantity. 35 transmission request signal lines This is a signal line for controlling the transmission function to the line of the modem.When the voltage is . Stop. The transmission enable signal line 36 is a signal line that handles the signal sent from the modem in response to the state of the transmission request signal +1135. Indicates that the message cannot be sent because the message is currently being sent. The data set ready signal line 37 is a signal line that indicates whether or not the modem is operable; ON indicates that the modem is operable; OFF indicates that the modem is inoperable. Data/Terminal Ready Signal l1j38V: This is a signal line that indicates whether or not the modem/interface device of the i device is operable. If it is 0Nf), the modem/interface device of the device is operable, and if it is OFF, it is not. Show that something is true. The data reception carrier detection signal line 39 is a signal line that indicates whether the received signal on the line is within a predetermined range.When communicating by FM modulation, the carrier wave (carrier) of the signal is detected and Indicates whether there is a possibility that received data will be sent. As mentioned above, the signal line of the modem connection interface device was originally provided to control the modem when communicating with the modem via the communication line, and was used to connect 1α connected devices. It was not established for mutual communication control. Therefore, when directly connecting devices, (1) the object to be controlled by signals must be changed from the modem or line to the modem connection interface device of the other device.

(2) The communication control procedure must be the same whether the devices are connected directly or via a modem.

FIG. 5 shows a typical conventional wiring connection method that satisfies these two conditions. Since the transmission data for one interface device is the reception data for the other interface device, the transmission data signal line and the reception data signal line are interchanged with each other. Also, since a transmission request for one interface device means that reception data for the other interface device may be sent, the transmission request signal line and the data reception carrier detection signal line are swapped with each other. ing. Furthermore, since there is no need to check whether the modem is operational, the data set ready signal line and the data terminal ready signal line are short-circuited to their respective interface sides. The transmission enable signal line is also connected to the transmission request signal line in response to a transmission request, since it is not necessary to check the operation of the modem and the congestion status of the line. In this connection method, mutual communication control is possible using the transmission request signal line and the data reception carrier detection signal line, and in response to the signal sent from the interface device, the same signal as when the modem is able to operate normally is returned. Therefore, you can use the same communication system as when connecting via a modem.

However, the conventional wiring method has the following drawbacks.

Conventionally, the connection work between the connector of the cable 20 and the cable wire has been done manually by soldering, which requires a lot of labor to manufacture. Recently, this work has been mechanized, and crimp-type cable processing equipment has come to be used. FIG. 6 shows the principle of the crimp-type cable processing device. 52 cables inserted into connector terminal 51 Connector cover 53
By crimping in the direction of the arrow, the vinyl coating of the cable is cut and the core wire of the cable is attached to the connector terminal 51.
come into contact with. When this crimp-type cable processing device is used, it is possible to realize a significant labor saving, that is, cost reduction, compared to the conventional soldering process using a handmade tool. However, when processing the cable to make the connection shown in Figure 5, contact 49.5
0, it is necessary to connect two cable wires to one terminal. Manual soldering is easy, but crimp-type cable processing equipment requires two or more cable wires to be inserted into a connector terminal. This is difficult to do with current technology, so it cannot be used. Therefore, when making the connection shown in FIG. 5, an expensive manually processed cable must be used.

[Purpose of the invention]

The purpose of the present invention is to enable connection of modem connection interface devices using a cable that can connect only one double-wire to the L terminal without a repeater and without impairing the modem connection function. The present invention provides a communication control signal line connection method between a processing device and an external device.

[Summary of the invention]

In the present invention, new terminals are added to the modem interface device and wiring is performed inside the interface device so that the same connection as in the conventional example can be made.

[Embodiments of the invention]

FIG. 7 is a block diagram of the modem-interface device 4 of the processing device. System bus interface 61
is connected to the system bus 13 and transfers control information and transmission/reception data to and from the CPUI. The communication control mechanism 62 handles parallel data handled on the system bus side (multiple bits of data are transferred simultaneously using multiple signal lines) and serial data handled on the modem (external device) side. It is a mechanism that performs mutual conversion with data (multiple bits of data are sequentially transferred bit by bit using one signal line) and input/output of communication control signals. Manufactured LSI” MC68
50", LSI "8251A" manufactured by Jnte1, etc.Modem interface circuit 63This circuit converts the signal voltage handled within the Vi processing device and the signal voltage handled by the modem, and is an embodiment of the present invention. The modem interface circuit 63 is different from the conventional example.

FIG. 6 is a circuit diagram of an embodiment of the i-modem interface F[63. As the driver 84, for example, 'l'e
A product equivalent to 8N75188 made by XAS Instrument is used, and a product equivalent to 5N75189 made by XAS Instrument is used for the receiver 85. In the present invention, compared to the conventional example, there are two terminals, CD' terminal 80 and R8' terminal 81, and CD terminal 79-CD' terminal 8.
0 and R8 terminal 75 to R8'8' terminal 81 are added, and the state of the data carrier detection signal input from CD terminal 79 is connected to CD' terminal 80 and R8'8' terminal 80.
R8' indicates the state of the transmission request signal output from the 8 terminal 75.
Terminal 81 is machined and outputs respectively. FIG. 1 shows a connection method for directly connecting modem ψ interface devices using this interface. The CD' terminal is connected to the C8 terminal of the other party's modem interface device 7 to form a transmittable circuit on the interface device 7 side, and the R8' terminal is connected to the C8 terminal of its own (interface device 4) and forms a transmittable circuit on the interface device 7 side. Configure a transmittable circuit. This connection method allows the use of an inexpensive crimp type cable that can connect only one signal line to one terminal of the connector.

FIG. 9 is a time chart of communication between interfaces when the connection method shown in FIG. 1 is used.

The contents of the communication are as follows: 1 piece of 8-bit data with Φ bits of parity is sent to the interface device 7 by the 4 interface devices, and then 8-bit data with φ bits of parity is sent from the interface device 7 to the interface device 4. This is synchronous half-duplex communication (a communication method that uses start/'stop bits to alternately transmit and receive). First, before starting communication, the interface device 4 turns on the data terminal ready ER. Since the data terminal ready output is connected to the data set ready input DRK of the interface device 4, the data
Set ready is turned on (timing 91). This operation is similarly performed at the data terminal ready and data set ready of the interface device 7. After confirming that the data set ready is ON, the transmission requests R, S, R, and S' of the interface device 4 are turned ON (timing 92).
).

The transmission request output of the interface device 4 is connected to the data reception carrier detection input CD of the interface device 7 and the transmission enable input C8K of the interface device 4 via the R8' terminal of the interface device 4, and receives the data reception carrier detection signal of the interface device 7, respectively. Since the line is connected to the transmission enable signal H of the interface device 4, the transmission enable signal of the interface device 4 and the data reception carrier detection of the interface device 7 are both turned ON (timing 93). By turning on the transmitting enable circuit, the interface device 4 becomes capable of transmitting operation, and the transmitting data circuit starts transmitting data (timing 94). Since the transmission data circuit of the interface device 4 is connected to the reception data signal line of the interface device 7,
Data is received by the interface device 7vC via the reception data signal line of the interface device 7 (timing 95). When the transmission is completed, the interface device 4 turns off the transmission requests R and S, and in response, the transmission enable of the interface device 4 and the data reception carrier detection of the interface device 7 are turned off (timing 96).
. Next, data is transmitted from the interface device 7 to the interface device 4. Since the transmission request signal line of the interface device 7 is connected to the data reception carrier detection signal line of the interface device 4, the transmission request of the interface device 7 is turned ON. As a result, data reception carrier detection of the interface device 4 is turned on (timing 97). The data reception carrier detection input of the interface device 4 is outputted from the CD' terminal via internal wiring. Since the CD ``;'m child is connected to the transmit enable signal line of the interface device 7, the transmit enable of the interface device 7 is turned ON (timing 98). Transmission of circuit error data is started (timing 99). The reception data signal line of the interface device 4 connected to the transmission data signal line of the interface device 7 receives this data (timing 100).
. After the transmission is completed, the interface device 7 sends the transmission request to 0FFL, and accordingly, the data reception carrier detection of the interface device 4 is turned OFF, and then the interface device 7 is turned OFF to enable transmission (timing 10).
1.102). When the communication is completed, both the interface devices 4 and 7 are set to data terminal ready OFF, and in response, data set ready is set to OFF, thereby completing the communication. As described above, the connection system shown in FIG. 1 can realize communication control using communication control signals of the modem using a connection cable to which only one signal line can be connected at one end. Further, in this embodiment, compared to the conventional example, only two terminals and two wires are added, so there is almost no increase in cost.

〔Effect of the invention〕

According to the present invention, two devices can be connected to each other via a modem connection interface using a cable that can connect only x cable lines from l end to f-, without a repeater, and without impairing the modem connection function. It is possible to use inexpensive cables that can be connected and manufactured using crimp-type cable processing equipment.

[Brief explanation of drawings]

Fig. 1 is a wiring diagram of an embodiment of the present invention, Fig. 2 is a diagram showing the connection form of a communication method via a modem and a communication line, which is the premise of the present invention, and Fig. 3 is a diagram showing the connection form of a communication system via a modem and a communication line, which is the premise of the present invention. Diagram 4 showing the form of direct connection between interfaces
The figure shows the connection method with the modem, Figure 5 shows the connection method in the case of conventional direct connection, and Figure 6 shows the principle of the crimp-type cable processing device to which the present invention is applied. figure,
7 and 8 are diagrams showing an embodiment for realizing the method of the present invention, and FIG. 9 is a diagram showing a time chart of the embodiment of the present invention. 4.7...Modem interface device, 20...
Communication cable, 63...Modem interface circuit, 80.81...Added terminal, 82.83...
wiring. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. A processing device and an external device are connected to each other by a communication cable that is physically detachable, and each of the processing device and the external device has a connection with the communication cable. As a signal connection terminal, in addition to the terminal for the transmission data signal and the reception data signal, there is also a first terminal that outputs a transmission request signal that is turned on when a transmission request is made, and a terminal that outputs a transmission request signal that is turned on when the request signal is turned on. In a communication control signal connection system having a second terminal for inputting a data reception carrier detection signal that is turned on and a third terminal for inputting a send enable signal that is turned on when transmission is possible, the signal between the processing device and the communication cable is Fourth and fifth terminals are provided as connection terminals, and the fourth terminal is internally connected to the second terminal, and is activated when the data reception carrier detection signal input to the second terminal is turned on. A communication control signal connection method between a processing device and an external device, characterized in that the signal is connected as a transmission enable signal and is configured to output the same signal as a transmission request signal outputted from a first terminal. 2. The communication cable according to claim 1 connects the first, second, and third terminals of the external device to the second, eleventh, and fourth terminals of the processing device, respectively, and A communication control signal connection method between a processing device and an external device, characterized in that a third terminal and a fifth terminal are connected.