JPS60180363A - Telephone terminal set - Google Patents

Abstract

PURPOSE:To open automatically a line at the same time when the transmission of an FAX signal is finished by providing a voltage polarity regulating means to an input side of a telephone set terminal having an on-hook dial function, providing a loop current detecting circuit to a DC loop circuit also and opening the said circuit when said current is detected. CONSTITUTION:A telephone terminal set TELa is provided with a loop detection circuit DET and a rectifier circuit REC is provided to fix the polarity. A pushbutton switch of the telephone set, a relay H is activated so as to close its contact h0, and after speaker reception SP is connected to the line via a contact h1 in place of a telephone set circuit Ta, the transmission button of the FAX is depressed by detecting the confirming tone. Thus, the transmission circuit is connected to the line side and the FAX signal is transmitted. In starting the transmission, since the TELa is disconnected from the line, a potential at a point P of a light emitting diode is changed. The H relay is restored by detecting the potential change. Thus, the line LINE is opened at the same time when the tranmission of the FAX signal is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) 1 Technical Field of the Invention The present invention relates to a telephone terminal, and particularly to a telephone terminal connected to a facsimile.

(b) Prior Art and Problems Recently, there have been many cases in which telephone terminals are used with various devices such as facsimile machines additionally connected thereto.

FIG. 1 is a schematic diagram showing an embodiment of a conventional telephone terminal connected to a facsimile machine.

FIG. 2 is a diagram explaining the operation of FIG. 1.

In the figure, LINE is the line, F is the facsimile, 5END is the transmitting circuit of the facsimile F, d is the contact of the switching relay D, POS is the telephone terminal, H3 is the hook switch, Ta is the telephone circuit, SP is the speaker receiving circuit, and h (1 and hl are the contacts of the switching relay H, respectively.The same reference numerals represent the same objects throughout the following description.

A conventional facsimile operating method will be explained below with reference to the drawings. When operating the facsimile F, the user goes off-hook on the telephone terminal side, closes the hook switch H3, makes a dial call, receives confirmation, and then presses the "send" button.

By pressing the "send" button, switching relay D is operated, and its contact d is operated, so that the transmitting circuit 5END of facsimile F is connected to line L'lNB and sends out a facsimile signal. If the telephone is on-hook when contact d of the switching relay is restored after transmission is completed, the line LINE will be released.

However, if the telephone is a one-touch dial type, the
Press the push button switch as shown in al to operate relay H and its contact point. is closed, and the contact h1 causes the speaker receiver circuit SP to connect to the line L instead of the telephone circuits T and a.
After connecting to INE, press the "Send" button on Facsimile F after detecting the confirmation tone.

Figure 2 (bl
As shown in FIG. 3, the contact d of the switching relay D operates, and the transmitting circuit 5END is connected to the line LINE and sends out a facsimile signal.

In this conventional method, when the relay contact d naturally recovers after sending the facsimile signal while heating, the second
Connect as shown in figure (C). Since LINE is in a closed state, the line LINE is in a loop closed state, and the line LINE is in a closed state.
E does not recover. There was a drawback in that the H-relay had to be restored manually using this high-side button switch.

(C)9 Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art;
To provide a telephone terminal capable of automatically opening a line upon completion of sending a facsimile signal.

(d) 9 Structure of the Invention According to the present invention, in a telephone terminal having an on-hook dialing function, means for defining voltage polarity is provided on the input side of the telephone terminal, and At least one loop current detection circuit using a photocoupler is provided in the DC loop circuit of the telephone terminal, and when the loop current detection circuit detects a loop current, the DC loop is switched off except when the telephone terminal is dialing or answering. This is achieved by providing a telephone terminal characterized by an open circuit.

Further, two sets of loop current detection circuits using photocouplers are provided in the DC loop circuit of the telephone terminal, and the light emitting parts of the two sets of photocouplers are connected in parallel with each other in opposite directions, so that the loop current detection circuit By providing a telephone terminal characterized in that when Rekahito Shirakawa detects a loop current, the telephone terminal opens the DC loop circuit except when the telephone terminal is dialing or hooking. This is accomplished without providing any means for defining polarity.

(e) 0 Embodiment of the Invention FIG. 3 is a schematic diagram showing an embodiment of a telephone terminal according to the present invention.

FIG. 4 is a diagram illustrating its operation.

In the figure, a is a telephone terminal according to the present invention, REC is a rectifier circuit, DIA is a dialing circuit, DET is a loop detection circuit, R1 is a resistor, and PC is a photocoupler.

The present invention will be described in detail below with reference to the drawings. According to the present invention, the telephone terminal device a shown in FIG. 3 is used instead of the telephone terminal device shown in FIG. 1, and in FIG. 3, the loop detection circuit DET detects whether or not the line is blocked. The rectifier circuit REC is a circuit for fixing the polarity. That is, which terminal L1 or R2 is positive is determined by the wiring, but in the present invention, the rectifier circuit REC is used because it is necessary to ensure that a forward current flows through the light emitting diode in the loop detection circuit DET.

As mentioned in the section on the prior art, if the telephone is of the one-touch type, the push button switch is pressed to operate the relay H as shown in FIG.

is closed, the speaker receiver SP is connected to the line instead of the telephone circuit Ta by the contact h1, and after detecting a confirmation tone, the "send" button of the facsimile F is pressed.

By pressing this "Send" button, the message shown in Figure 4 fc)
As shown in the figure, the contact d of the switching relay operates, and the transmitting circuit 5
END is connected to the line side and sends out facsimile signals. When the facsimile signal transmission starts, the telephone terminal device a according to the present invention is disconnected from the line, so the loop detection circuit D
No current flows to the light emitting diode inside the ET, and Figure 4 f
As shown in b), the potential at point P changes. This potential change is detected and the H relay is restored.

Therefore, as soon as the sending of the facsimile signal is completed, the
The line LINE is opened as shown in l.

FIG. 5 is a schematic diagram showing another embodiment of the telephone terminal according to the present invention.

In the figure, position b is another telephone terminal according to the present invention, DETa is a loop detection circuit according to the present invention, R' is a resistor, and PC' is a photocoupler.

As described in the explanation of FIG. 3, the rectifier circuit REC is used when the voltage polarities of the terminals L1 and L2 are not determined, but the present invention shows an embodiment in which the rectifier circuit REC is not used.

The loop detection circuit DETa according to the present invention is composed of a bidirectional loop detection circuit, and when the terminal L1 has a higher potential than the terminal L2, the photocoupler PC operates, and the terminal L1 is connected to the terminal L2.
When the potential is lower than 2, the photocoupler PC' operates.

Therefore, the relay H can be restored by a change in the potential at points P and P'', and the line can be opened at the same time as sending of the facsimile signal is completed.

In this case, not only can the loop detection circuit DETa detect whether the DC loop is on or off, but also the reversal of polarity can be detected using the loop detection signal (change in potential at points P and P'). Therefore, it can also be used, for example, to count call time.

Figure 6 shows the potential of relay H1, relay D1, point P, point P'', and line usage status in the above explanation.The potential of point P and the potential of point P' depend on the polarity of the line. change.

(f) 1. Effects of the Invention As explained in detail above, according to the present invention, it is possible not only to realize a telephone terminal that can automatically open the line upon completion of sending a facsimile signal, but also to detect reversal of the polarity of the line. There are great effects that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a conventional telephone terminal connected to a facsimile machine. FIG. 2 is a diagram explaining the operation of FIG. 1. FIG. 3 is a schematic diagram 7 showing an embodiment of a telephone terminal according to the present invention. FIG. 4 is a diagram illustrating the operation of FIG. 3. FIG. 5 is a schematic diagram showing another embodiment of the telephone terminal according to the present invention. FIG. 6 is a diagram illustrating the operation of FIG. 5. In the figure, F is a facsimile, 5END is a transmitting circuit of facsimile F, d is a contact of switching relay D, is a telephone terminal, H3 is a hook switch, Ta is a telephone circuit, SP is a speaker receiving circuit, ho and hl are respectively The contacts of the switching relay H, location a is the telephone terminal according to the present invention, REC is the rectifier circuit, DIA is the dialing circuit, DET is the loop detection circuit, R, and R' are resistors, and pc and pc' are the photovoltaic terminals, respectively. coupler, position b is another telephone terminal according to the invention, DE
Ta is a loop detection circuit according to the invention. (LnD sh'c-1--------J--------
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l/NE Tada 5in 7NE

Claims (1)

[Claims] 1. In a telephone terminal having an on-hook dialing function, means for regulating voltage polarity is provided on the input side of the telephone terminal, and a photocoupler is provided in a DC loop circuit of the telephone terminal. At least one loop current detection circuit is provided for use, and when the loop current detection circuit detects a loop current, the DC loop circuit is opened except when the telephone terminal is dialing or answering. telephone terminal. 2. Two sets of loop current detection circuits using photocouplers are provided in the DC loop circuit of the telephone terminal, and the light emitting parts of the two sets of photocouplers are connected in parallel with each other in opposite directions to detect the loop current. The telephone terminal according to claim 1, characterized in that when one of the Shirakawa circuits detects a loop current, the telephone terminal opens the DC loop circuit except when the telephone terminal is dialing or dialing. Machine.