JPS6076854A - Data terminal device - Google Patents

Abstract

PURPOSE:To prevent the starting mistakes of other terminal devices by providing a circuit between a terminal device and a telephone line to prevent a data transmitting AC signal while one of plural data transmitting terminal devices connected to a telephone line is transmitting data. CONSTITUTION:Terminal devices A1 and B101 and a telephone set 201 are connected to telephone lines 11 and 12. When the device A1 is under a data communication mode, a contact 33 is broken by a relay 31. At the same time, a contact 34 is made by a relay 32. With break of the contact 33, the data transmission signal is prevented from leaking out to the device B101. A capacitor 35 is charged with make of the contact 34. Under such conditions, a DC loop is formed for calling of the set 201 or the device B101. Then the capacitor 35 is discharged and a hook-off detecting circuit 10 works to inhibit the actuation of the device A1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a terminal device in a take transmission system using a general subscriber telephone line, and more specifically to a terminal device in which a single subscriber telephone line is connected to two in addition to the above. In situations where terminal devices are shared for take transmission, data terminal devices that have been carefully designed to avoid the evolution of one device or the start-up operation of another device are used. .

<Background> In recent years, water, waste, chambers, air, etc. have been used, automatic meter reading for logging, various types of electricity installed only in trenches, +! Small-sized data scattered over a wide area, such as monitoring ji, etc., and surveying the usage of vending machines, is generated from the master station to the slave stations in order! The most effective way to collect data in short time is to transmit data using a general Soviet telephone line (hereinafter referred to as a telephone line).
Attention has been paid. When transmitting data using such a telephone line, the cost of the system (interconnection) can be reduced by #large size A's 7 leaves & shares - no 1 hat.It is no exaggeration to say that the cost of the system In order to reduce costs, it is not a good idea to use the front power source as the operating power source, and instead the central power source from the exchange is used as is.

Recently, public facsimile machines that use general subscriber telephone lines as tX have become popular for home use, and are devised so that calls can be received per call using a special signal from a special facsimile communication network.

However, when two terminal devices with automatic call receiving functions, such as automatic meter reading and public facsimile, are connected together to a single telephone line, the data transmission signal of one terminal device There is a risk that the other device may be forced to start up. For example, if a special single frequency signal other than 16Hz (- or pulse) from the exchange side is generated for one ψ4i (terminal device), the frequency modulation (polarization) of the data communication of the other terminal device is It is conceivable that the single frequency component in the spectrum caused by the frequency (FS) signal may cause erroneous activation.

<Object of the Invention> The object of the invention is to prevent each other from influencing the other when two data terminal devices having an automatic receiving function such as an automatic side and a public facsimile are connected to a single telephone line. An object of the present invention is to provide a data terminal device that can perform a correct startup operation without having to do so. Another object of the present invention is to provide a data terminal device that allows telephone calls to be given priority over other data transmissions, and at the same time prevents erroneous activation due to the voice of the fourth episode. Our goal is to provide the following.

<Summary of the Invention> In the present invention, when two terminal devices each use a special single frequency signal as an activation condition, the terminal device located at the higher level with respect to the telephone line transmits at least a small amount of data during its own data transmission. Inserting a circuit that deactivates transmission signals into the communication path to lower-level terminal equipment prevents the lower-level terminal equipment from erroneous activation, and also detects the DC loop of higher-priority lower-level equipment when it is operating. to prevent its own accidental activation. In this case, the terminal equipment that uses the central power supply is located at the top of the telephone line, and the terminal equipment that uses the central power supply is usually located at the lowest level.
The ingredients are elevated.

<Example> Hereinafter, an example of the invention will be described in detail with reference to the drawings.

In the figure, 1 is a terminal device (5) according to the present invention, 40 in the terminal device I (5) is a part including a signal blocking circuit and an off-hook detection circuit, which are the key points of this invention, and IQ.
I ld the other terminal device t fB), 203 is a telephone. The terminal device (a) 1 operates using the local power source, and the terminal device 101 operates using the commercial power source 1. In the terminal device 1, the two diodes 2 are
The polarity of I and 12 is opposite to that when the phone is on standby./This 11
! J is on L27, a capacitor 5 is inserted into the center tap on the primary side of the coupling transformer 30 for the father flow signal, and this is 7 from λ1.
The connection wires 3a and 3b to the a source circuit 6 are taken out 4
, a single frequency receiving circuit 7 is connected to the secondary side of the transformer 3, and includes a modulation/modulation section for data communication via a switch circuit 8, a data processing section, and an interface section with external equipment. It is connected to the connection line 16 of.

In the section 40, the relay contact 33 is the contact of the relay 31 which is controlled to break when the terminal device f (All) enters the data communication mode, and the contact 34 is similarly controlled to make when the terminal device f (All) enters the data communication mode. Relay 3 controlled by
The off-hook detection circuit 10, which is the contact point of 2, and which detects that the lower terminal device FB+ 101-i take phone 12oz has made a call, that is, has formed a DC loop, connects the contact point 34, the charging capacitor 35, and the resistor 36 to jφ. terminal 21.2
Connected between the two. After the off-hook detection circuit 1o detects this, the off-hook detection circuit 1o turns off the off-hook circuit 8 via the control line 14. The connecting line 13id is a line that controls the switch circuit 8 when a single frequency signal is received by the receiving circuit 7, and the connecting line 15
are current supply lines for the power supply circuit 6 and each part of the terminal device (5), and terminals 21 and 22 are terminal device fit (Al
and terminal equipment (Bl 10 i ”f, or telephone clerk 2o1
This is the connection terminal.

This terminal device (branch) 1 is a station from telephone lines 11 and 12.
It uses the it, j source (7, and is designed to start and operate with a reverse polarity and single frequency signal.In addition, when in data communication mode, the relay contact 34 is first made and the capacitors 3 and 5 are connected. Charge and store the potential from the line,
Next, the relay contact 33 breaks and works to prevent leakage of data transmission signals such as the FFI signal to the lower terminal device 1B and the telephone 201 when the data 1111 is input. Terminal device fB) 1 during data communication
When '01 or telephone 201 forms a DC loop for making a call, the energy stored in the capacitor 35 flows through the DC loop, and the off-hook detection circuit 1° detects the call. Normally, relay contact 33 (rL make, contact 34 is broken and data can be passed. Among them, relay contact 34, capacitor 35, and resistor 'dl; :36 have a sufficiently high impedance for the telephone line side in terms of AC. I keep it.

1jli terminal device FB+ Next, in the i/lTh terminal device FB+ 101, an AC signal coupling transformer 103, a DC blocking capacitor 105.1-sink inserted in the primary side of the transformer 103]03
The transmission circuit 109 is connected to the secondary side of the transformer 03 via a single frequency receiving circuit 107 and a switch circuit 108 connected to the secondary side of the transformer. Transmission circuit 109
consists of a modulation/demodulation section and a data processing section for performing final data communication.

The off-hook detection circuit 110 detects that the telephone 201 is in use, and the switch circuit 10 detects that the telephone 201 is in use.
Turn off 8. Resistor 132 for automatic incoming call response
A switch 131 for creating a DC termination is connected between terminals 1] and 112, and the switch 131 is controlled by the transmission circuit 109. A current supply line 115 from the TV circuit 106 that uses commercial power is connected to the terminal device (B
It is connected to each part of l. Terminals 121 and 122 are telephone 2
01 connection terminal. This terminal device (13) 101
It operates using an external commercial power source, and is designed to automatically wake up a call only when it receives a predetermined single frequency signal.

If we consider normal data communication with 2 ji (j is a frequency modulated signal, whose spectrum is determined by the ratio of 1:+, the frequency between marks/spaces (+:6) and the dot frequency. is the frequency determined by the JJfI speed and the pattern component of logic 1 or 0 (for details, see "Data Transmission", published by Cityis 1, translated by Shogo Ri, etc.).This 6::Una spectrum has different levels. appears as various frequency components depending on the code being passed, and
This may lead to the erroneous activation of the terminal device 1 due to switching to a single frequency, which is the activation condition for the i-terminal device.

. In Jin's invention, in order to prevent false activation due to the spectrum of the FS (N, etc.) during data communication, the lower terminal p-: ij
I': (B) At least a data transmission intersection jf? such as a relay contact 33- or a band-eliminating P-wave device is connected to the trace path connected to 16e of 101. , a circuit is inserted to stabilize the signal 1, and furthermore, when the lower terminal device 101 is in operation, J-7y 19'+:ll
i++4乍b low+l-eggplant r J-kr? h off-hook detection times 1 to 410 to prevent false activation due to data transmission signal interruption of other terminal devices or telephone voice, etc.;
110 is provided. This off-hook detection circuit can also serve as a priority determination circuit that can simultaneously stop the data communication of this terminal device by a high priority terminal device or telephone connected to the next stage or later.

<Effects> As described above, according to the present invention, one subscriber telephone line can be connected to a telephone and at least two data processing devices (At, (
The multi-purpose high reliability shared by Bl" will be realized by the communication system.In addition, among the 6 brothers, the 4-terminal installation (3) of this invention is explained in 17 as using the local power supply (↓II t, but 6. Although the AC blocking circuit has been described using relay contacts, any circuit that can block data transmission signals may be used.The off-hook detection circuit is also just one example.In summary, the AC blocking circuit of the present invention and off-hook detection circuit -] ψ"lX: end device (although it is assumed that it can be included in
City of Leh Ore,? Sakutomi sword 1. Therefore, consider batteries, etc. as the energy for the cold output.

[Brief explanation of the drawing]

Figure (d) is a connection and block diagram of a terminal device according to Akira Hontsu.
toc+, : transmission circuit, ], ]0, 110 : off-fluid output circuit, ]-i, ]-2: subscriber telephone line, 1
01: Terminal device, 201: Telephone. Agent WJ Takashi

Claims (2)

[Claims] (1) In a device in which two or more terminal devices for data transmission are connected to one subscriber telephone line, a circuit is installed to prevent at least the take transmission AC/1g from passing during data transmission. , is inserted into the connection communication path between another terminal device and the above telephone line, and other 11
? ii. q11' to prevent the terminal device from starting up accidentally.
A data terminal device with a characteristic. (2) One subscriber': Take two lines of transmission to the telephone line.
In a device to which three or more terminal devices are connected, a circuit for preventing at least the AC line 48 for data transmission from passing through is connected to one other terminal device and the other terminal device. ■An old coin inserted into the connection communication channel with the 2 telephone lines.”
(2) Detecting that another terminal device is in a calling state,
A data terminal device characterized in that it is equipped with an off-hook detection circuit for stopping the sequential operation of the data terminal device, and prevents erroneous start-up of the data terminal device.