JPH0124388B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a push-button dial telephone in which power is supplied to a multi-frequency signal generating section only when a key is pressed. The aim is to eliminate signals with abnormal frequencies.

Recent push-button dial telephones (hereinafter referred to as PB telephones) always use multi-frequency (hereinafter referred to as MF
A method is adopted in which the power to the signal generating section (abbreviated as ) is turned off and turned on temporarily only when one of the dial push buttons is operated in synchronization with the operation. However, according to this method, the MF signal is sent immediately after the oscillation operation is unstable immediately after the power is turned on, so the frequency of the sent MF signal deviates from the specified value, especially in the first part, and the exchange may malfunction.

The present invention aims to improve this point, and its feature is to send out a multi-frequency signal that selectively combines one wave from the low group and one wave from the high group according to the pressed key. In a push-button dial telephone, in which the power of a multi-frequency signal generating section having a function is turned on for the necessary time in accordance with the depression of any key on the key input section, the key interface circuit receives key operation information from the key input section. , if the pressed key is a numeric key, a certain period of time after pressing the key;
a first control signal generation means for prohibiting the transmission of the multifrequency signal; and a second control signal generation means for prohibiting the transmission of the multifrequency signal for a certain period of time after pressing the key when the pressed key is a function key. and turning on and off the power supply of the multi-frequency signal generation unit in synchronization with the period during which the number key is pressed, and an instruction to continue powering on outputted from the second control signal generation means in accordance with the press input of the function key. comprising a power supply control circuit that keeps the power supply turned on for a certain period of time by receiving a signal, and a control signal that prohibits transmission of the multi-frequency signal output from the first control signal generation means; and the second control signal generation means. The point is that the output of the multi-frequency signal is controlled by performing an OR logic with a control signal that prohibits the transmission of the multi-frequency signal outputted from the control signal. This will be explained in detail below with reference to illustrated embodiments.

FIG. 1 is a diagram showing one embodiment of the present invention, and is a schematic configuration diagram showing the entire PB telephone. In the same figure, L is the line (central office line) connected to the exchange side,
HYB is a hybrid circuit, BN is a balanced network,
RAMP is the receiving amplifier, R is the receiver, T is the transmitter,
TAMP is the transmitting amplifier, MFSG is the MF signal generator,
KIF is a key interface circuit, and KEY is a key input section for dialing. MF signal generator
MFSG is a programmable counter PCTR _L for generating low group frequencies, a programmable counter PCTR _H and a ring counter for generating high group frequencies.
A mixer that combines the outputs of RCTR _H and ring counters RCTR _L and RCTR _H (one wave each for low group and high group).
MIX, and an oscillator OSC that uses a crystal oscillator X'tal to provide a clock of about 1 MHz to the programmable counters PCTR _L and PCTR _H. Key input section
KEY generally includes 10 numeric keys indicating 0 to 9 and 2 function keys. When the key interface circuit KIF receives the key operation information from the key input unit KEY, the key interface circuit KIF receives the key operation information from the key input unit KEY.
indicates the power supply line), and one wave of the low group L ₁ to _{L 4} and one wave of the high group H ₁ to _{H 4} corresponding to the key operation information are turned on.
Necessary values are preset in the programmable counters PCTR _L and PCTR _H so that one wave of the signals is sent out at the same time. Programmable counter PCTR _L ,
PCTR _H receives and counts the output of the oscillator OSC, and the overflow pulse is counted by the ring counter.
RCTR _L and RCTR _H are driven, and the ring counter generates low group and high group frequencies.

In the present invention, the above key interface circuit KIF
In addition, a control signal MFC is generated that prohibits the transmission of MF signals for a certain period of time after the power of the MF signal generator MFSG is turned on until the operating state of the oscillator OSC becomes stable.
It has a generation function. A specific example of this will be explained with reference to FIGS. 2 and 3. Figure 3 shows the MF signal sending control signal MFC in the key interface circuit KIF.
1 is a configuration diagram of the part that generates the power control signal POW ON. 1 is the MFC that generates the control signal MFC' in response to key input IN ₁ associated with normal dial operation.
The control circuit 2 is a key input IN ₂ associated with a redial operation (memorizing the number of the previous caller and then calling the caller again using a function key, etc.) or a repertoire re-dial operation (memorizing the caller's number in advance). A signal transmission time control circuit that generates a control signal MFC'' in response to a key input IN ₃ (an operation that is memorized and called up using a speed dial); 3 is an MF signal generation section;
This is a power control circuit that generates the power control signal POW ON that controls the power on and off of the MFSG.

When the input from the key input unit KEY is IN ₁ , IN ₁ is intermittently turned on for the period of time when the key is pressed according to the caller's number, as shown in FIG. 2a. Power supply control circuit 3 outputs POW in synchronization with this input IN _1.
Turn ON on and off. On the other hand, the MFC control circuit 1 turns on the output MFC' with a delay of a certain time t after IN ₁ turns on. This output MFC' becomes an MF signal transmission control signal MFC through an OR gate 4 and AND gates 5 and 6. The falling edge of the communication MFC may be delayed by t than the falling edge of the signal POW ON, but may be simultaneous as shown. If at the same time, the first period t of the period T ₁ during which power is applied to the MF signal generator MFSG from POW ON
Only the remaining period T ₂ except counter RCTR _L ,
RCTR _H becomes operational and the MF signal is sent during this period, but normally the key press time is long enough so there is no particular problem. If the rise is delayed by t, the oscillator OSC will stabilize its operation during this time and can send out MF at a predetermined frequency. In this regard, conventionally, the MF signal was sent out immediately after the power was turned on, so the frequency of the MF signal during the period t during which the oscillation operation was unstable was not guaranteed. In the present invention, even if key input IN ₁ is received, the FM signal transmission period is limited to T ₂ during which the oscillation operation is stable, so malfunctions on the exchange side are prevented.

If the input from the key input section KEY is IN ₂ or IN ₃ as shown in Figure 2b, the other party's number will be read out from the memory even after the key operation is finished.
Sends MF signal. Therefore, when the signal transmission time control circuit 3 receives the input IN ₂ /IN ₃ , it sends a signal CNT to the power supply control unit 3 instructing the output POW ON to remain on for a certain period of time, and
A control signal MFC'' is generated with a delay of t from the rising edge of ON. Each rectangular wave of MFC'' corresponds to that of MFC', but of course it is not synchronized with each key press, but a continuous wave with a predetermined period. Since the power remains on, only the first wave has the delay time t. In the case of redial or repertoire redial, the key input prohibition signal INH prevents the control signal MFC' from being output by mistake due to normal key operation.
MFC" becomes the MF signal transmission control signal MFC through gates 4 to 6. Gates 5 and 6 are open under normal conditions, but if the high group key is pressed twice or the low group key is pressed twice, Then, it closes due to the detection signal and prevents the output of the signal MFC.

As described above, according to the present invention, it is possible to prevent a power-saving PB telephone in which the power is turned on to the MF signal generating section only when necessary, from sending out a signal with an abnormal frequency immediately after a key operation. can do.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention;
FIGS. 2 and 3 are waveform diagrams and blocks showing essential parts of the present invention. In the figure, KEY is the key input section, KIF is the key interface circuit, MFSG is the multi-frequency signal generation section,
IN ₁ to IN ₃ are key inputs, POW ON is a power control signal, and MFC is a multifrequency signal transmission control signal.

Claims (1)

[Scope of Claims] 1. A power supply of a multi-frequency signal generating section having a function of transmitting a multi-frequency signal in which one wave from the low group and one wave from the high group are selectively combined according to a pressed key, In a push-button dial telephone that is turned on for the required time in response to the pressing of any key on the key input section, a key interface circuit that receives key operation information from the key input section is provided with a key that applies when the pressed key is a numeric key. a first control signal generating means for prohibiting the transmission of the multi-frequency signal for a certain period after pressing a key; and a first control signal generating means for prohibiting the transmission of the multi-frequency signal for a certain period after pressing the key when the pressed key is a function key; turning on and off the power of the control signal generating means of No. 2 and the multi-frequency signal generating section in synchronization with the period during which the number key is pressed;
The first control signal generating means includes a power control circuit that keeps the power on for a predetermined period of time by receiving an instruction signal to keep the power on, which is output from the second control signal generating means in response to a press input of the function key. a control signal for prohibiting transmission of the multi-frequency signal output from the second
1. A push-button dial telephone, characterized in that the transmission of the multi-frequency signal is controlled by performing an OR logic with a control signal for prohibiting the transmission of the multi-frequency signal output from the control signal generating means of the telephone.