JPS6345958A - Line connection device - Google Patents

Abstract

PURPOSE:To improve the reliability of signal input/output between the titled device and a data processing unit and to make the device small in size and light in weight by connecting a telephone line and a communication line via a resistance hybrid circuit, a 2/4-wire conversion speech network circuit and a magnetic coupling means. CONSTITUTION:The device is connected to a line via a diode 20. An output signal of a speech network circuit 17 is inputted to the primary winding of a transformer 21 via a DC blocking capacitor. The output of the secondary winding of the transformer 21 is inputted to an amplifier 14 via a DC blocking capacitor 24. The output of the amplifier 14 is fed to a MODEM 10. On the other hand, the output of the MODEM 10 is given to the primary winding of the transformer 22 via a DC blocking capacitor 26 and the secondary output is inputted to the speech network circuit 17 via the DC blocking capacitor 25. The DC and AC impedance viewed from the telephone line are kept within a prescribed reference value by the resistance hybrid circuit and the speech network circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a line connection device, and particularly to a line connection device for connecting various data processing devices such as computer systems, facsimile machines, and word processors to telephone lines.

[Prior Art] In various data processing systems that apply microprocessor elements, such as facsimile machines and personal computers, devices are connected via telephone lines and communication is performed between devices installed in far away locations. The method is known. The data that can be sent through a telephone line may include images, 9 characters, and other digitized data, but 2
Wire telephone lines are originally analog lines intended for transmitting voice signals, and have a relatively small passband, so when inputting and outputting data to the line, analog modulation and demodulation processing based on methods such as differential phase modulation is required. is required. In addition, in order to achieve both the traditional transmission of voice signals and the transmission of various data via telephone lines, this type of data processing equipment, which is different from telephone voice terminals, uses line connection equipment that meets predetermined standards. connection to the line.

One of the important conditions for this connection is that the line side and the data processing device side be DC-insulated.

FIGS. 3 and 4 show conventional configurations for connecting a line and a data processing device while satisfying the above conditions. In the configuration shown in FIG. 3, the data processing device and the line are directly connected via a modem. In the figure, reference numeral 1.1 is a connection terminal for connecting a telephone line. This connection terminal is equipped with a polarity reversal detection circuit 2 for detecting a response from the other party when making an automatic call. A calling signal detection circuit 8 is connected to detect a calling party when automatically receiving a call. Connection and disconnection between the telephone line and the data processing device are controlled by a hook switch 4. The hook switch 4 is composed of a relay element and is driven via the driver 3. The telephone line side and the data processing device side are insulated by a direct current blocking transformer 7.

Also, set the DC resistance of the terminal as seen from the telephone line side to 50 to 30.
In order to set the AC impedance to 0Ω and 800Ω,
A choke coil 5 and a capacitor 6, which can flow a direct current of 100 mA or more and have a reactance of about IH, are connected. The capacitor 6 is a non-polar and high voltage 2
．． A value of about 2 pF is used.

A hybrid circuit 9 that separates a transmission signal and a reception signal is connected to the output side of the transformer 7, and the separated output signal is input to the modem 10 via an amplifier 14. Also,
The output signal of modem 10 is input to hybrid circuit 9 via amplifier 15. The modem 10 performs analog modulation and demodulation of input/output signals for the line in accordance with various standards such as CCI TT, and exchanges input/output data in a digital signal format such as TTL level with the data processing device 13. do. A dial signal generation circuit 12 is provided which generates a dial signal of a predetermined format, such as a dial pulse or dial tone, and applies it to an amplifier 15 in accordance with data output by the data processing device for automatic dialing.

[Problems to be Solved by the Invention] When implementing the above configuration, there are two methods: a method of integrating the data processing device and the above structure, a method of connecting a modem and a line connection unit between the data processing device and the line, or Various configurations are conceivable, such as a system in which the above configuration is further provided with a communication circuit, etc., and the telephone, processing device, and connection device are all integrated. However, in either configuration, it is necessary to provide a capacitor for direct current isolation and a choke coil for impedance matching seen from the line side. These elements have a large inductance and a large capacitance as described above, and therefore have a large shape, making it difficult to miniaturize the overall structure of the device.

In the configuration shown in FIG. 4, in view of the above-mentioned problem, a polarity-crossover diode 20 and a resistive hybrid circuit 16 are used to connect the line and the data device side. That is, through these, the DC impedance seen from the telephone line side is approximately matched to the above value. In the configuration shown in FIG. 4, separation of input and output signals is performed by a resistive hybrid circuit 16, which is also connected to a two-wire terminal circuit consisting of a speaker 18 and a microphone 19 using a condenser microphone, a condenser speaker, etc. Tame Speech Network 17
is provided. The speech network circuit is composed of integrated circuits and the like.

In such a configuration, connection to the data processing device 13 is made by a connection means such as an acoustic coupler including a modem, and insulation from the data processing device side is also performed by this acoustic coupler.

According to the configuration shown in Fig. 4, there is no need to use large-capacity choke coils or capacitors, so it is possible to make the telephone for connecting the data processing device smaller and lighter, but data input and output is performed using audio signals. Therefore, there are problems in that reliability is low and high-speed data transmission is impossible.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a direct current connection between the data processing device and the two-wire telephone line is provided between the data processing device and the data processing device. In a line connection device having a communication circuit that connects in an insulated state and performs signal conversion of transmitted and received signals by a predetermined method between the two to perform data communication between a data processing device and a telephone line, the telephone line and the communication circuit A configuration was adopted in which the resistive hybrid circuit is coupled to the speech network circuit for 2-wire/4-wire conversion and via magnetic coupling means.

[Function] According to the above configuration, the terminal device side connected to the telephone line side can be electrically interrupted by the resistance hybrid circuit, the speech network circuit, and the magnetic coupling means.

[Example] Hereinafter, the present invention will be described in detail based on the implementation shown in the drawings. Hereinafter, the same reference numerals will be given to constituent members that are the same as or correspond to those of the above-mentioned conventional example, and detailed explanation thereof will be omitted.

FIG. 1 is a block diagram showing the configuration of a line connection device according to the present invention. In this embodiment, as in the case of Fig. 4,
A connection to a line is made via a diode 20. The configuration from the diode 20 to the speech network circuit 17 is the same as that shown in FIG. The output signal of the speech network circuit 17 is sent to the transformer 21 via a DC blocking capacitor (low withstand voltage and capacity of about 0.IJLF).
is input to the primary winding of the The output of the secondary winding of the transformer 21 is input to the amplifier 14 via the same DC blocking capacitor 24 as described above. The output of the amplifier 14 is the modem 10
is input.

Meanwhile, the output of modem 10 is also coupled in a similar manner. That is, the output of the modem 10 is input to the primary winding of the transformer 22 via the amplifier 15 and the DC blocking capacitor 26, and the output on the secondary side is input to the DC blocking capacitor 25.
The signal is input to the speech network circuit 17 via.

With this configuration, the DC and AC impedances seen from the telephone line side are maintained within predetermined standards by the diode-coupled resistive hybrid circuit and the speech network circuit. In addition, according to this embodiment, the transformer that insulates the telephone line and the terminal processing device after the modem is not used for loop maintenance, and no direct current flows, so it can be smaller than a conventional choke coil. In addition, DC blocking capacitors can be made with lower withstand voltage and smaller capacitance.
The entire circuit can be configured to be significantly smaller and lighter.

FIG. 2 shows a modification of the configuration of FIG. 1.

In FIG. 2, in addition to the configuration shown in FIG. 1, a speaker 8 and a microphone 19 are added. These speakers 8 and microphone 19 constitute the handset of the telephone, and are connected to transformers 21 and 22, respectively.
Connected in parallel to the primary and secondary windings.

With such a configuration, the line connection device and the telephone can be easily integrated, and manual calls can be made and received.

[Effect] As is clear from the above, according to the present invention, it is provided between a data processing device and a two-wire telephone line, connects the line and the data processing device in a DC-insulated state, and In a line connection device having a communication circuit that performs signal conversion of transmitted and received signals according to a predetermined method between the two to perform data communication between a data processing device and a telephone line, the telephone line and the communication circuit are connected to a resistive hybrid circuit and a two-wire / Since it uses a configuration in which coupling is performed through a speech network circuit for 4-wire conversion and magnetic coupling means, the device is significantly smaller and lighter than the conventional circuit coupling method using choke coils and capacitors. In addition, the reliability of signal input/output between the data processing device and the data processing device can be greatly improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of a line connection device adopting the present invention, Fig. 2 is a block diagram showing a modification of the circuit in Fig. 1, and Figs. 3 and 4 respectively show conventional lines. FIG. 2 is a block diagram showing the configuration of a connecting device. 2... Polarity reversal detection circuit 4... Hook switch 13... Data processing device 14.15... Amplifier 1
6... Resistance hybrid circuit 17... Speech network circuit 21.22... Transformer

Claims (1)

[Claims] It is installed between a data processing device and a two-wire telephone line, and connects the line and data processing device in a DC-insulated state, and performs signal conversion of transmitted and received signals between the two using a predetermined method. In a line connection device having a communication circuit for performing data communication between a telephone line and a telephone line, the telephone line and the communication circuit are connected to a resistive hybrid circuit and a two-wire/
A line connection device characterized in that it is coupled via a speech network circuit for four-wire conversion and magnetic coupling means.