JPH0113261B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching system for a dial signal system of a communication line.

Currently, two types of dial signal systems are used for communication lines: a direct current dial pulse signal (hereinafter referred to as DP signal) and a multifrequency dial signal (hereinafter referred to as MF signal). The DP signal is mainly used as a line selection signal to select the other party's terminal.
In addition to being used as a line selection signal, MF signals are also used for telephone calculation services, Shinkansen reservation services, etc.
It is also used as a means of communicating data, etc. with a terminal on the other end.

Lines that currently receive and identify dial signals using DC dial pulse signals (hereinafter referred to as DP lines)
When using various services or data communications using MF signals, the circuit that generates the DP signal and
A circuit that generates an MF signal is provided, and a circuit that sends out a DP signal is first driven to select a line using the DP signal. Thereafter, the circuit is switched to the circuit that sends out the MF signal, and the MF signal is sent out.

Conventionally, switching between the DP signal and the MF signal was done manually by operating a switch or the like. For this reason, the user is required to perform a switching operation during a call, which is not only extremely troublesome, but also may result in disconnection of the line if the user makes a mistake in the switching operation. For example, after calling the other party's terminal using a DP signal,
Or after answering an incoming signal and entering the talking state.
If you forget to switch to MF signal and operate the dial switch, the line may be disconnected.

Also, switch to the mode that sends MF signals and
After the signal transmission is finished, the mode must be restored to the DP signal transmission mode.

In order to improve these shortcomings, there is a method in which a means is provided to detect that the other party's terminal has responded, and the detection output automatically switches from the DP dial circuit to the MF dial circuit (Japanese Patent Application Laid-Open No. 1983-1999).
(See No. 44257). This method sends a line selection signal using a DP signal, and when the other party's terminal responds, the MF dial is switched to an operational state.
When transitioning from a call operation to a call state, data communication using MF signals can be performed without any manual operation. However, if you want to perform data communication using MF signals after answering an incoming call and entering the talking state, you still have to manually switch the dial mode by operating a switch, etc., which causes troublesome switching operations. problem has not been completely resolved.

In order to eliminate these drawbacks, the present invention includes means for detecting that an incoming call has been answered and means for detecting that the other party's terminal has responded. The present invention provides a dial mode switching system configured to automatically switch the dial mode from a dial pulse transmission mode to a multifrequency signal transmission mode when a response is received.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which 1 is a connection terminal with a line, 2 is a switch for opening and closing the DC loop, 3 is a communication circuit, and 4 is a DP signal generation circuit (first dial circuit). , 5 is an MF signal generation circuit (second dial circuit), and 6 is a dial push button switch. Further, 7 is a switch interface circuit, and this circuit 7 includes a decoder, absorbs chatter and poor contact of the dial push button switch 6, and shapes the signal waveform when the switch is pressed. Press button information for dial push button switch 6
This signal is transmitted to the DP signal generation circuit 4 and the MF signal generation circuit 5. Reference numeral 8 denotes an incoming call circuit consisting of a bell or tone ringer circuit. 9 is an incoming call response detection circuit (first detection circuit) that detects a response to an incoming call, and 9a is a detection output. 10 is a detection circuit (second detection circuit) that detects that the other party's terminal has responded, and 10a is a detection output. Methods for detecting a response from a terminal on the other end include a method of detecting that the polarity of the line is reversed when the terminal on the other end responds, and a method of detecting the presence or absence of a ringback tone. 11 is power-on reset (P.
This is a circuit (OR) circuit which has a contact point that interlocks with the switch 2 and generates a reset output 11a for a certain period of time when the switch 2 is closed and the DC loop is closed. 12 is the DP signal generation circuit 4
12a is an output that operates the DP signal generation circuit 4, 12b is an output that operates the MF signal generation circuit, and 12a and 12b are complementary outputs. It is in. The input/output signals of the control circuit 12 are the power-on reset signal 11a, the incoming call response detection output 9a, and the other party's terminal response detection output 10a. After the power-on reset signal 11a is input, the output 12a operates the DP signal generation circuit 4. Output 9a
Alternatively, after inputting 10a, it is configured to output 12b.

Next, the operation of this embodiment will be explained. When you turn off the hook to make a call and close the switch 2, the contact that works with the switch 2 turns the P.
The O/R circuit 11 operates, and the control circuit 12 outputs an output 12a that operates the DP signal generation circuit 4 in response to the power-on reset output 11a. When the dial switch 6 is operated in this state, the switch information of the pressed switch is inputted to the DP signal generation circuit 4 via the switch interface circuit 7, and a dial pulse signal is sent out.

When the transmission of a series of dial pulse signals is completed and the other party's terminal responds, the detection output 10a of the other party's terminal response detection circuit 10 is input to the control circuit 12, and the control circuit 12 outputs an output that operates the MF signal generation circuit 5. 12b is output, and when the dial switch 6 is operated from this point on, the MF dial signal is sent out.

When an incoming call signal (calling signal) is answered, the control circuit 12 outputs an output 12b that operates the MF signal generation circuit 5 based on the output 9a of the incoming call response detection circuit 9, so when the dial switch 6 is operated, MF dial signals can be sent.

FIG. 2 shows a specific example of the power-on reset circuit 11 and control circuit 12 used in the embodiment of FIG. In FIG. 2, 11-1 is a contact that operates in conjunction with the switch 2 of FIG. 1, 11-2 is a resistor, 11-3 is a capacitor, and 11-4 is an inverter. In addition, 12-1 is an OR circuit, 12-
2 is a set/reset type flip-flop.

In the power-on reset circuit 11, when the contact 11-1 linked to the switch 2 is closed,
The configuration is such that a rising pulse determined by the time constant of a resistor 11-2 and a capacitor 11-3 is obtained from the output of an inverter 11-4. This power-on reset signal 11a resets the set-reset type flip-flop (hereinafter referred to as FF) 12-2, and the Q output of the FF 12-2 goes to "L" level and the output goes to "H" level. , the DP signal generation circuit 4 becomes operable and the MF signal generation circuit 5 becomes inoperative.

Next, if either the incoming call response detection output 9a or the other party's terminal response output 10a is input to the OR circuit 12-1, the output of the OR circuit 12-1 causes the FF1
2-2 is set, and the output Q of FF 12-2 is inverted to "H" level and to "L" level.

Therefore, the DP signal generation circuit 4 becomes inoperative, and the MF signal generation circuit 5 becomes operable.

As explained above, according to the present invention, by providing a DP signal generation circuit, an MF signal generation circuit, a circuit for detecting that an incoming call has been answered, and a circuit for detecting that the other party's terminal has responded, The DP signal generation circuit operates when dialing, and automatically switches to the MF signal generation circuit after the other party answers or after the incoming call is answered, allowing the user to switch the dialing mode on the DP line. This has the advantage that various services can be realized through terminal-to-terminal communication, etc., without requiring any operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a circuit diagram including blocks showing an example of a power-on reset circuit (P.O.R.) and a control circuit used in the embodiment of FIG. 1. 4...First dial circuit, 5...Second dial circuit, 9...First detection circuit, 10...Second
detection circuit, 11, 12... control circuit.

Claims (1)

[Claims] 1. A first dial circuit that generates a dial pulse signal, a second dial circuit that generates a multi-frequency dial signal, a first detection means for detecting a response to an incoming call, and a terminal at the other end. a power-on reset circuit that detects an off-hook state and outputs a reset output; and a power-on reset circuit that detects an off-hook state and outputs a reset output; and the second dial circuit respectively between an operable state and an inoperable state, and in a state where the power-on reset circuit outputs the reset output, the first detection means or the second detection means is controlled. A dial mode switching system comprising: a control circuit that controls switching of the first dial circuit and the second dial circuit to an inoperative state and an operable state, respectively, when a detection output of the means is received.