JPH0535589Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an RS232C interface connector that connects computers to each other via a connection circuit and serially transmits data, and in particular isolates the computer and the connection circuit. RS232C
The present invention relates to a connector for an interface.

[Prior Art] Recently, with the spread of microcomputers and personal computers, it has become necessary not only to use a single computer, but also to connect the computers to each other and perform data communication in order to make effective use of the data stored in each computer. It's starting to look like this. When connecting these computers to each other for data communication, use the RS232C interface, which is an interface for serial transmission, to connect two computers or to connect multiple computers to the same transmission path. In order to do this, we created a simple network interface based on Ethernet (a local area network jointly developed by Xerox, Intel, and DEC) that incorporates transistors so that an RS232C interface can be used, as shown in Figure 3. has also been proposed.

[Problem that the invention aims to solve] However, it is difficult to transmit data serially.
The RS232C interface is originally a standard for connecting a computer and a modem (modulator/demodulator), and depending on the communication method, it simplifies the number of connection wires and makes connection relatively easy, but it also reduces the length of the connection cable to 15m. If the cable is set above this value, the capacitance of the cable becomes large, which has the disadvantage that it is easily affected by external noise. Therefore, in a bus-type network using a simple network interface made of transistors, etc., computers are directly electrically coupled to the same long transmission path, which makes them more susceptible to external noise and noise from the power supply.
It is conceivable that this may cause computer malfunction or data corruption.

In view of the above points, the present invention proposes an RS232C interface connector that aims to electrically insulate the connection circuit of the RS232C interface and make it less susceptible to noise.

[Means for Solving the Problems] In order to achieve the above-mentioned objectives, the present invention uses an RS232C interface RXD (receive data) that connects computers to each other and serially transmits data.
A high-speed optical coupling isolator is inserted into the reception connection circuit connected to the reception connection circuit and the reception connection circuit connected to the TXD (transmission data) terminal, and the VCC (power supply) terminal of the high-speed optical coupling isolator of the reception connection circuit is connected to the The RS232C is characterized in that a power supply circuit is provided to directly operate the high-speed optical coupling isolator by coupling the RST (request to send) terminal of the RS232C interface, and both high-speed optical coupling isolators are housed inside a small connector. The present invention provides an interface connector.

[Function] In the present invention, the RS232C interface installed in the computer and the transmission line are connected in an electrically insulated state using a high-speed optical coupling assolator. Current due to noise does not flow to each device, and noise is no longer propagated. Then, the power to the VCC terminal of the high-speed optical coupling isolator inserted in the receiving connection circuit is always outputted as a carrier signal during data communication, and the power is set to high level.
Since it is taken from the RTS terminal, the high-speed optical coupling isolator of the receiving and transmitting circuits can be housed in a small connector, and a small RS232C connector with noise countermeasures can be constructed.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

Figure 1 shows an example of a network configured by connecting multiple computers to one bus-like transmission line. 1 is a personal computer that processes and stores various data, and a modem (modulator/demodulator) ) has a built-in RS232C interface 2. Reference numeral 3 denotes a coaxial cable forming a bus-like transmission path for transmitting data to each personal computer 1, which has a power supply section 4 at its end and a plurality of T-shaped branch connectors 5 at appropriate locations in the middle. A personal computer 1 is connected to the computer. Reference numeral 6 denotes a connection cable for connecting the RS232C interface 2 to the T-shaped branch connector 5. An RS232C interface connector 7 is provided at one end of the connection cable 6, and a T-shaped branch is provided at the other end. Connector 5
A connector 8 is provided to be connected to. this
The RS232C connector 7 has a 25-pin plug (not shown) connected to the input/output port of the RS232C interface 2 and houses a high-speed optical coupling isolator therein.

Figure 2 is a circuit diagram of the RS232C connector 7, and the left side of the figure is the RS232C interface 2.
Each pin connected to the input/output port is arranged, and the connection terminal of the connection cable 6 is arranged on the right side of the figure. A receiving high-speed optical coupling isolator 9a is arranged in the center of the receiving circuit above the circuit,
The anode and cathode of the isolator 9a on the light emitting element side are wired to be connected to the connection cable 6 via an LED. In addition, the RXD (reception data) and RTS (transmission request) terminals leading to the signal pin of the RS232C interface 2 are connected to the collector and VCC (power supply) terminal of the output transistor on the light receiving element side of the reception isolator 9a, A carrier signal is sent to the RTS terminal during data communication, and the fact that it is always at a high level is used as a driving power source for the transistor of the receiving isolator 9a.

In addition, a transmission high-speed coupling isolator 9b is provided at the lower center of the circuit in the opposite direction to the reception isolator 9a, and TXD (transmission data) is connected to the anode and cathode of the transmission isolator 9b to the signal pin of the RS232C interface 2. and SG (signal ground) terminal are connected. The emitter of the output transistor is further wired to be connected to a connection cable 6 via a transistor. Also, connect the connection cable 6 to the VCC terminal.
The drive power is supplied from a power supply unit 4 connected to the terminal and connected to the coaxial cable 3 using a transmission line.

Thus, a plurality of personal computers 1 are connected using an RS232C connector with a built-in high-speed coupling isolator 9, and the personal computers 1 and the transmission line coaxial cable 3 are connected in a state where they are electrically insulated by the light emitting element and the light receiving element. When transmitting data from the personal computer 1, a carrier signal, which is a transmission request signal, is first sent to the RTS terminal of the RS232C interface 2, and as voltage is applied to VCC of the receiving isolator 9a, the transmitted data is transmitted from the TXD terminal. A signal corresponding to the data is applied between the anode and cathode of the light emitting element of the transmitting isolator 9b, causing the light emitting element to emit light. The light receiving element receives the received light, converts it into an electrical signal, amplifies it, and sends it to the transmission line coaxial cable 3.

Furthermore, when data is taken into the personal computer 1 from the transmission line coaxial cable 3, the data signal is transferred to the receiving isolator 9 on the transmission line.
The light emitting element a is caused to emit light, transmitted to the light receiving element, converted into an electrical signal, and sent to the RXD terminal, which is then captured as data.

At this time, the ground of the RS232C interface 2 and the transmission coaxial cable 3 is disconnected, and even if a potential difference occurs between the devices due to noise coming from the power supply or external noise, no current will flow, so noise will not be propagated. Data communication can be performed without being affected by noise.

[Effect of the invention] When a plurality of personal computers 1 are connected to each other via a bus for small-scale data communication, the personal computers 1 can be connected to the transmission coaxial cable 3 using the RS232C connector 7 with a built-in high-speed optical coupling isolator 9. By connecting them, an electrically insulated bus-like network can be constructed, which is less susceptible to noise and improves the reliability of data communication.

Also, the power to the VCC terminal of the high-speed optical coupling isolator inserted in the receiving connection circuit is always outputted as a carrier signal during data communication, and the power is set to high level.
Since it is directly connected to the RTS terminal, the high-speed optical coupling isolators for the receiving and transmitting circuits can be housed in a small connector, making it possible to create a small RS232C connector with noise countermeasures.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the connector of the present invention, Figure 2 is a diagram showing an example of a bus-like network configured using the connector of the present invention, and Figure 3 is a circuit diagram of a conventionally proposed connector. FIG. 2 is a circuit diagram showing a simple network interface in which a transistor is incorporated into an RS232C interface. 1...Computer, 2...RS232C interface, 3...Coaxial cable, 4...Power supply section,
5...T-shaped branch connector, 6...Connection cable, 7...RS232C interface connector,
8...Connector, 9a...Receiving isolator,
9b...Transmission isolator.

Claims (1)

[Scope of utility model registration request] A receiving connection circuit that connects computers to each other and connects to the RXD (receive data) terminal of an RS232C interface that serially transmits data;
Insert a high-speed optical coupling isolator into each transmission connection circuit connected to the TXD (transmission data) terminal,
High-speed optical coupling isolator for receiving connection circuit
A power supply circuit is provided that directly operates the high-speed optical coupling isolator by connecting the RST (request to send) terminal of the RS232C interface to the VCC (power supply) terminal, and both high-speed optical coupling isolators are housed inside a small connector. characterized by having done
Connector for RS232C interface.