JPH07107199A - Terminal equipment for data communication - Google Patents

Abstract

PURPOSE:To decrease the loss of power consumption and a signal level by supplying electric power only to one of a DTMF generating means or a detecting/analyzing means, based on transmitting and receiving permission signals supplied from a control means. CONSTITUTION:When a microcomputer 53 detects data supply from a consumption meter, a transmitting permission signal is sent out to an electric power supply selection switch 12. As a result, the electric power supply selection switch 12 applies a voltage of 5V to a DTMF (multiple frequency) dialer 13, a low-pass filter 15, and an amplifier 16 and drives the DTMF dialer 13, the low-pass filter 15, and the amplifier 16. In such a state, after data are transmitted, in the case a DTMF signal sent back from a host side is supplied, the cmicrocomputer 53 sends out a receiving permission signal to the electric power supply selection switch 12 after the data transmission is conducted. Accordingly, the electric power supply selection switch 12 applies the voltage of 5V only to a DTMF detection analyzer 17, and the DTMF detection analyzer 17 becomes an operating state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication terminal device using a telephone line, and a data communication terminal device for transmitting / receiving data by a dual tone multi-frequency signal.

[0002]

2. Description of the Related Art Conventionally, a telephone line is used to provide a multi-frequency (dual-tone multi-frequency) signal transmitter and a detector / analyzer for detecting and analyzing a received DTMF signal. ,
There is a data communication terminal device for bidirectional communication that transmits and receives data by a DTMF signal. In such a communication terminal device, only the transmitting device functions and the detection / analysis device is in a dormant state at the time of transmitting the DTMF signal,
On the contrary, when the DTMF signal is supplied and only the detection and analysis device functions during the detection and analysis of the DTMF signal, the transmission device is in the dormant state. However, the DTMF signal transmitter and D
In a conventional data communication terminal device equipped with a TMF signal detection / analysis device, power is supplied to both the transmission device and the detection / analysis device regardless of transmission / reception, resulting in high power consumption. There is. In particular, in a data communication terminal device in which the transmitter and the detection / analysis device use a battery provided in the data communication terminal device as a driving power source, the power consumption is large. This is a serious problem because it is largely related to the operating time of the device. Further, conventionally, the impedance at the output of the transmission device and the detection / analysis device is matched with the line impedance of the telephone line, so that the amplified DT is transmitted at the time of transmission.
There is also a problem that the level loss is large until the MF signal is transmitted to the telephone line, and the signal level loss supplied to the detection / analysis device at the time of signal reception is large. The present invention has been made to solve such a problem, and an object of the present invention is to provide a data communication terminal device that consumes less power and has less signal level loss.

[0003]

According to the present invention, a line transformer having a primary side connected to a telephone line and a DTMF signal supplied from the telephone line with an input side connected to the secondary side of the line transformer are provided. DTMF to detect and analyze
The detection / analysis means and the output side are connected to the secondary side of the line transformer, and have DTMF creating and sending means for creating and sending a DTMF signal showing the data content, and the DTMF showing the data content sent by the DTMF creating and sending means. A data communication terminal device for transmitting a signal through the line transformer using the telephone line, wherein the output side of the DTMF detection / analysis means and the input side of the DTMF creation / transmission means are connected to each other for transmission. The transmission permission state is set based on the data supply, and the reception permission state is set based on the data transmission end signal included in the data. On the other hand, during the data communication, the data supplied from the DTMF detection / analysis means. The transmission permission state is set based on the supply of the transmission end signal, and the transmission permission state is set in accordance with the transmission permission state or the reception permission state. A control means for sending a permission signal or a reception permission signal, an input side is connected to the power supply means, an output side is connected to the DTMF detection / analysis means and the DTMF making and transmitting means, and the transmission permission signal is supplied from the control means. At times, power is supplied to the DTMF creation / transmission means and power is not supplied to the DTMF detection / analysis means. When the reception permission signal is supplied from the control means, power is supplied to the DTMF detection / analysis means.
And a power supply selection unit that does not supply power to the TMF creation and transmission unit.

With this configuration, the power supply selection means supplies power to only one of the DTMF creation / transmission means and the DTMF detection / analysis means based on the transmission permission signal and the reception permission signal supplied from the control means. Therefore, the power consumption is reduced.

Further, according to the present invention, the DTMF creating and transmitting means is such that the input side is connected to the control means and indicates the data content based on the data supplied from the control means.
A DTMF dialer that creates a signal, and the DTM that is connected in series between the output side of the DTMF dialer and the secondary side of the line transformer and sent by the DTMF dialer.
An amplifier for amplifying the F signal may be provided, and further, the secondary side line of the line transformer and the D
A first resistor connected in series between a connection point of the TMF detection / analysis means with the input side line and the output side of the amplifier;
Second connection in series with the input side line of the TMF detection / analysis means
A resistor, and the primary side of the line transformer and 2
The impedance on the next side may be 600 ohms, the resistance of the first resistor may be less than 600 ohms, and the resistance of the second resistor may be greater than 600 ohms.

With such a configuration, the power supply selecting means does not supply power to the amplifier at the time of reception, and therefore operates so as to bring the output side of the amplifier into a high impedance state at the time of reception. Further, making the resistance value of the second resistor larger than the impedance of the secondary side of the line transformer acts so as to bring the secondary side of the line transformer into a high impedance state during reception. In this way, the power supply selection means and the second resistor act so that the supplied DTMF signal is transmitted to the DTMF detection / analysis means with a small transmission loss. Further, since the power supply selecting means does not supply power to the DTMF detection / analysis means during transmission, it operates so as to set the input side of the DTMF detection / analysis means to a high impedance state during transmission. Further, setting the resistance value of the second resistor larger than the impedance of the secondary side of the line transformer acts so as to bring the input side of the DTMF detection / analysis means into a high impedance state during transmission. Further, making the resistance value of the first resistor smaller than the impedance on the secondary side of the line transformer acts to reduce the transmission loss of the DTMF signal from the amplifier to the line transformer. In this way, the power supply selection means, the first resistor and the second resistor act so that the amplified DTMF signal is transmitted to the telephone line with a small loss.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a data communication terminal device of the present invention will be described below with reference to FIG. The data communication terminal device 1 of the present embodiment is for bidirectional communication for transmitting and receiving data by DTMF signals. Terminals L1 and L2 in the terminal device 1 for data communication in the present embodiment
Is connected to a telephone line, and terminals T1 and T2 are connected to a home telephone. The terminals L1 and L2 and the terminals T1 and T2 are connected to the divider 50, respectively, and the terminals L1 and L2 are connected to the terminals 2 and 3 of the relay 52 via the divider 50 and the filter 51. The slicing device 50 is switched between the "TEL" side and the "AUTO" side, and is normally switched to the "AUTO" side, and when an accident occurs in the data communication terminal device 1, " By switching to the "TEL" side, the telephone line is forcibly connected to the home telephone. The terminal of the divider 50 connected to the home telephone when the divider 50 is switched to the "AUTO" side is
It is connected to the terminals 5 and 7 of the relay 52 through the call detection circuit 8 which detects the usage state of the home telephone. Also, relay 5
The terminals 4 and 6 of 2 are connected to the line control circuit 9 described later. The relay 52 connects either one of the terminals 4 or 5 and the terminal 2 and one of the terminals 6 or 7 and the terminal 3, that is, a telephone line is used as the terminal device 1 for the present data communication. Or, it connects to either one of the home telephones. Also, normally, the terminal 2 of the relay 52
Is connected to the terminal 5 and the terminal 3 is connected to the terminal 7, and the relay 52 connects the telephone line with the filter 51, the call detection circuit 8 and the disconnector 5.
0 is connected to the home telephone, and when the data communication is performed, the call detection circuit 8 detects that the home telephone is not in use, and then the microcomputer 5
The terminal 2 of the relay 52 is connected to the terminal 4 and the terminal 3 is connected to the terminal 6 by the control signal sent from the relay 52. The relay 52 connects the telephone line and the terminal device 1 for data communication via the filter 51.

The line control circuit 9 has a function of producing a rotary dial pulse (hereinafter referred to as DP) transmission signal, an off-hook function, and an on-hook function. After the connection with the telephone line is made by the relay 52, the off-hook state is established. Is set. Such a line control circuit 9 is used for the line transformer 5
4 and the input side of the full-wave bridge circuit 10. The output side of the full-wave bridge circuit 10 is connected to the power supply selection switch 12 via a DC / DC converter 11 that generates a 5V voltage.

On the other hand, the secondary side of the line transformer 54 is connected to the input side of the DTMF detection analyzer 17 via the second resistor 56. Further, the output side of the DTMF detection analyzer 17 is connected to the microcomputer 5 via the level converter 18.
3 is connected. The DTMF detection analyzer 17 uses the DTMF
When the signal is supplied, the data transmission end signal which is a part of the DTMF signal is detected and analyzed, and the data transmission end signal is sent to the microcomputer 53 via the level converter 18. The second resistor 56 is connected to the secondary side line of the line transformer 54 and the DTMF detection analyzer 1
7 are connected in series to the input side line.

The data output terminal of the microcomputer 53 is connected to the DTMF dialer 13 via the level converter 14. The DTMF dialer 13 is a level converter 1
The contents of the data supplied from the microcomputer 53 via 4 are created as DTMF signals and sent out.
The low-pass filter 15, the amplifier 16 and the first resistor 55 are connected in series to the output side of the DTMF dialer 13.
The first resistor 55 is a connection point between the secondary side line of the line transformer 54 and the input side line of the DTMF detection analyzer 17,
It is connected to the output terminal of the amplifier 16.

The data communication terminal device 1 is driven by electric power from a built-in lithium battery, and the operating voltage of the microcomputer 53 is 3.6 V which is the lithium battery voltage. Analyzer 17
Of the level converter 14 connected to the output side of the microcomputer 53 operates to convert the voltage of the signal from 5V to 3.6V.
Performs an operation of converting the voltage of data from 3.6V to 5V.

The impedances of the primary side and the secondary side of the line transformer 54 are both 600 ohms, the resistance value of the first resistor 55 is 220 ohms, and the resistance value of the second resistor is 22K ohms.

On the other hand, the output side of the power supply selection switch 12 is connected to the DTMF dialer 13, the low-pass filter 15, the amplifier 16 and the DTMF detection analyzer 17, respectively, and the power supply selection switch 12 is supplied from the microcomputer 53. The power supply destination is selected by the control signal. That is, when transmitting a DTMF signal, the power supply selection switch 12 supplies the transmission permission signal sent from the microcomputer 53 to the DTMF dialer 13, the low-pass filter 15, and the amplifier 16. Power is supplied, while no power is supplied to the DTMF detection analyzer 17. On the other hand, when receiving a DTMF signal, the reception permission signal sent from the microcomputer 53 is supplied to the power supply selection switch 12, so that the power supply selection switch 12 supplies power only to the DTMF detection analyzer 17. Power is not supplied to the DTMF dialer 13, the low-pass filter 15 and the amplifier 16.

The microcomputer 53 switches between the transmission permission signal and the reception permission signal as follows. As will be described later, a sensor and the like are connected to the microcomputer 53 via an interface. When data is supplied from the sensor to the microcomputer 53, the microcomputer 53 detects the supply of the data to set the transmission permission state and sends a transmission permission signal.
Further, by recognizing the completion of transmission of the data transmission end signal included in the above data, the reception permission state is set and the reception permission signal is transmitted. After the data communication is started in this manner, the transmission permission signal is sent out based on the data transmission end signal included in the DTMF signal supplied from the host side. That is, as is well known, since the transmission end signal indicating the end of the transmission of the data is added to the data transmitted by the DTMF signal, the transmission end signal is transmitted by the DTMF detection analyzer 17 to which the DTMF signal is supplied. Detection analysis of
The DTMF detection analyzer 17 sends the transmission end signal to the microcomputer 53 via the level converter 18. The microcomputer 53 receives the supply of the transmission end signal, sets the transmission permission state, and sends out the transmission permission signal in response thereto. In this way, data communication is performed between the host side and the terminal device 1 for data communication, and when the microcomputer 53 detects an end signal for ending the communication, the microcomputer 53 ends the data communication.

Further, the amplifier 16 is connected with a gain switching circuit 57 for switching the gain so that a DTMF signal having a signal level conforming to the regulation is created and transmitted based on a control signal supplied from the microcomputer 53 in the transmission state. ing. Further, the data communication terminal device 1 in this embodiment can be connected to, for example, a fuel gas consumption meter, and the microcomputer 53 is connected to the above consumption meter via the interfaces 58 and 59. Connectors 60 and 61 are connected. Further, the interface 58 is connected to a connector 62 for writing data in a semiconductor memory provided in the microcomputer 53. The number and types of connectors are not limited to those described above.

The operation of the data communication terminal device 1 in this embodiment having the above-described configuration will be described below. Normal,
Since the divider 50 has been switched to the "AUTO" side,
The home telephone is connected to the telephone line via the call detection circuit 8, the relay 52, and the filter 51. On the other hand, when a signal is supplied from the external device, for example, the gas consumption meter described above, to the microcomputer 53 via the connectors 60, 61, etc., the microcomputer 53 sends the information supplied from the consumption meter to the telephone line. Start preparing to send. That is, the microcomputer 53
Drives the call detection circuit 8 to determine whether or not a call is currently in progress. When it is determined that the call is not in progress, the microcomputer 53 drives the relay 52 and switches the contacts connected to the terminals 5 and 7 in the relay 52 to the terminals 4 and 6. By this switching, the telephone line and the data communication terminal device 1 are connected via the filter 51 and the relay 52.

By connecting the telephone line and the terminal device 1 for data communication in this manner, the telephone line goes off-hook, and the full-wave bridge circuit 10 is connected to the telephone line via the line control circuit 9. The DC / DC converter 11 connected to the output side of the full-wave bridge circuit 10 generates a 5V voltage with the power supplied from the telephone line, and applies the 5V voltage to the power supply selection switch 12.

On the other hand, since the microcomputer 53 detects the data supply from the consumption meter, the microcomputer 53 sets the transmission permission state and sends the transmission permission signal to the power supply selection switch 12. Therefore, the power supply selection switch 12 applies a voltage of 5 V to the DTMF dialer 13, the low-pass filter 15, and the amplifier 16 to set the D
TMF dialer 13, low-pass filter 15, amplifier 1
6 is driven. On the other hand, the power supply selection switch 12
The above voltage is not applied to the DTMF detection analyzer 17, so that the DTMF detection analyzer 17 is in the inoperative state.

Next, the microcomputer 53 sends the information supplied from the consumption meter as 4-bit data to the level converter 14, and the level converter 14 converts the supplied data into 5V. DTMF dialer 13
Send to. The DTMF dialer 13 creates a DTMF signal based on the supplied data, and sends the above data as a DTMF signal. The DTMF signal sent from the DTMF dialer 13 is supplied to the amplifier 16 via the low pass filter 15. With the control signal supplied from the microcomputer 53, the gain switching circuit 57 causes the amplifier 16
Is set to a predetermined gain, the amplifier 16 amplifies the supplied DTMF signal at the set amplification factor, and the amplified DT
The MF signal is sent to the secondary side of the line transformer 54.

The winding ratio of the primary side and the secondary side of the line transformer 54 is 600 ohms to 600 ohms (1: 1), and the first resistor 55 connected to the output side of the amplifier 16 is used.
Since the resistance value of is set to 220 ohms, which is smaller than the conventional 600 ohms, the level loss of the signal between the amplifier 16 and the line transformer 54 can be reduced, and the DTMF signal appearing on the primary side of the line transformer 54 can be reduced. Can be made higher than before. still,
The impedance of the primary side of the line transformer 54 is matched with the impedance of the telephone line. Further, as described above, the DTMF detection analyzer 17 is in the inoperative state, and the resistance value of the second resistor provided in the input part of the DTMF detection analyzer 17 is larger than the conventional 600 ohms.
Since it is 2K ohms, the input side of the DTMF detection analyzer is in a high impedance state. In this way, the level of the DTMF signal can be easily secured when the DTMF signal is transmitted. The DTMF signal sent from the line transformer 54 is sent to the telephone line via the line control circuit 9, the relay 52, the filter 51, and the divider 50.

A case where the DTMF signal returned from the host side is supplied after the above-described data transmission will be described. At this time, the relay 52 connects the telephone line and the line control circuit 9 as in the transmission. After the data is transmitted as described above, the microcomputer 53 sets the reception permission state and sends the reception permission signal to the power supply selection switch 12. Therefore, the power supply selection switch 12
Applying a voltage of 5V only to the DTMF detection analyzer 17,
TMF dialer 13, low-pass filter 15, amplifier 1
No voltage is applied to 6. Therefore, the DTMF detection / analysis unit 17 is in the operating state.

The DTMF signal sent from the host side and supplied from the telephone line through the divider 50, the filter 51, the relay 52 and the line control circuit 9 appears on the secondary side of the line transformer 54. When the DTMF signal is supplied, the amplifier 16 is in the high impedance state because the amplifier 16 is in the inoperative state as described above. further,
Further, as described above, since the resistance value of the second resistor provided in the input part of the DTMF detection analyzer 17 is larger than that of the conventional one,
The secondary side of the line transformer 54 is in a high impedance state. Therefore, the supplied DTMF signal is DT
It can be transmitted to the MF detection analyzer 17 with a small loss. In addition, both the primary side and the secondary side of the line transformer 54 are 600 ohms.
Since the resistance values of the resistors are both 600 ohms, the data communication terminal device 1 can obtain a gain increase of at least 6 dB as compared with the conventional device.

In this way, the DTMF signal is supplied to the DTMF detection analyzer 17, and the DTMF detection analyzer 17 receives the D signal.
The transmission end signal attached to the TMF signal is detected, and the detection signal is sent to the level converter 18. Level converter 18
Converts the above detection signal into a voltage of 3.6 V and sends it to the microcomputer 53. As a result, the microcomputer 53 brings the data communication terminal device 1 into the transmitting state again as shown in FIG. Further, the microcomputer 53 detects the end of communication provided in the DTMF signal supplied from the host side, so that the microcomputer 53
Ends the data communication.

As described above, in the data communication terminal device 1, since the DTMF dialer 13 and the like and the DTMF detection analyzer 17 are alternately supplied with power, the power consumption of the data communication terminal device is reduced. This can be reduced, and in particular, in a data communication terminal device of a type driven by a battery having the DTMF dialer 13 and the like and the DTMF detection / analyzer 17 built therein, the operable time can be extended as compared with the conventional case. .

Since the DTMF dialer 13 and the like and the DTMF detection analyzer 17 are alternately supplied with electric power, the DTMF dialer 13 and the DTMF detection analyzer 17 do not operate at the same time. It is possible to prevent the DTMF detection / analysis device 17 from malfunctioning due to noise generated when the device operates.

[0026]

As described above in detail, according to the present invention, since the power supply selecting means is provided, the DTMF creating / transmitting means or the DTMF detection / analysis means based on the transmission permission signal and the reception permission signal supplied from the control means. Since power is supplied to only one of the means, it is possible to reduce power consumption.

Further, according to the invention described in claims 2 to 6, electric power is supplied to only one of the DTMF creating and sending means and the DTMF detecting and analyzing means, and the resistance value of the first resistor is set to that of the line transformer. Make it smaller than the impedance on the secondary side and set the resistance value of the second resistor to 2
By making the impedance larger than the impedance on the secondary side, the transmission loss of the DTMF signal from the amplifier to the line transformer can be reduced during transmission, and the amplified DTMF signal can be transmitted to the telephone line with little loss, and reception of the DTMF signal is possible. Sometimes DTMF with little loss to DTMF detection and analysis means
A signal can be transmitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a data communication terminal device of the present invention.

FIG. 2 is a diagram for explaining the operation of the data communication terminal device shown in FIG.

[Explanation of symbols]

9 ... Line control circuit, 10 ... Full wave bridge circuit, 11 ... D
C / DC converter, 12 ... Power supply selection switch, 13 ...
DTMF dialer, 15 ... Low-pass filter, 16 ... Amplifier, 17 ... DTMF detection analyzer, 53 ... Microcomputer, 54 ... Line transformer, 55 ... First resistor, 5
6 ... Second resistance.

Claims (6)

[Claims] 1. A line transformer whose primary side is connected to a telephone line, and a DTMF detection / analysis means for detecting and analyzing a DTMF signal supplied from the telephone line, the input side being connected to the secondary side of the line transformer, The DTMF showing the data contents with the output side connected to the secondary side of the line transformer
DTMF creating and sending means for creating and sending a signal,
A data communication terminal device for transmitting a DTMF signal indicating the content of data transmitted by the DTMF creating and transmitting means using the telephone line via the line transformer, the output side of the DTMF detecting and analyzing means and the DTMF. The input side of the creating and transmitting means is connected, and the transmission permission state is set based on the supply of the data to be transmitted, and the reception permission state is set based on the data transmission end signal included in the data. In this case, the transmission permission state is set based on the supply of the data transmission end signal supplied from the DTMF detection and analysis means, and the transmission permission signal or the reception permission signal is set in correspondence with the transmission permission state or the reception permission state, respectively. The control means for sending out, the input side is connected to the power supply means, and the output side is the DTMF.
It is connected to the detection / analysis means and the DTMF creation / transmission means, and when the transmission permission signal is supplied from the control means, power is supplied to the DTMF creation / transmission means to generate the D
No power is supplied to the TMF detecting / analyzing means, and when the reception permission signal is supplied from the control means, the DT
A data communication terminal device, comprising: a power supply selection unit that supplies power to the MF detection and analysis unit and does not supply power to the DTMF creation and transmission unit. 2. The DTMF creating and sending means includes a DTMF dialer whose input side is connected to the control means and creates a DTMF signal indicating data contents based on data supplied from the control means, and an output side of the DTMF dialer. 2. The terminal device for data communication according to claim 1, further comprising: an amplifier connected in series with the secondary side of the line transformer for amplifying the DTMF signal transmitted by the DTMF dialer. 3. The data communication terminal device according to claim 1, wherein the power supply means is the telephone line. 4. The data communication terminal device according to claim 1, wherein the power supply means is a battery provided in the data communication terminal device. 5. A first resistor connected in series between a connection point between a secondary side line of the line transformer and an input side line of the DTMF detection / analysis means and an output side of the amplifier, and the DTMF detection / analysis. A second resistor connected in series to the input side line of the means, and the impedance on the primary side and the secondary side of the line transformer is 600 ohms,
The resistance value of the first resistor is less than 600 ohms,
5. The data communication terminal device according to claim 2, wherein the second resistor has a resistance value of more than 600 ohms. 6. The data communication terminal device according to claim 5, wherein the first resistor has a resistance value of 220 ohms, and the second resistor has a resistance value of 22 K ohms.