JPS6232863B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a system for selectively calling multiple stations using a push-button telephone. Conventionally, when calling a specific station on the route in an area connected by a round-trip telephone line route (for example, a construction zone for constructing a new wired relay line), it was necessary to connect the telephone to the telephone line attached to the cable. If the transmitting side sends the area code, place name, etc. from the telephone transmitter, it will be uttered from all the receivers of other stations, so when the operator near the telephone notices it, he can pick up the receiver and answer the telephone. I was able to make a call. This method is extremely simple, but because all stations are on standby, the noise is amplified, especially when the call signal is amplified through speakers, increasing the noise level during construction. Also, since calls from stations other than the own station can always be heard through the speaker, it is necessary to always be careful to only answer calls from the own station, which has many drawbacks. Therefore, a combination of a push-button telephone, a push-button signal oscillator, and a push-button signal receiver was proposed as a calling system that has a station selection function without being in a constant reception standby state. One of the buttons
When this button is pressed, the oscillator output is transmitted to all other stations, and the receiving side judges whether the signal is assigned to its own station or not.When a signal is generated at the output of the pushbutton signal receiver, a buzzer sounds. Since current push-button telephones have 12 buttons, it is possible to selectively call up to 12 stations. However, when calling 13 or more stations, the selection function is insufficient, so you must use a switch and connection lines, and even if it is a small switch, it is an expensive device, and in order to ensure stable operation, it requires a housing including a power supply. It is uneconomical to prepare. SUMMARY OF THE INVENTION An object of the present invention is to provide a system in which a relatively simple calling/receiving device is added to a push-button telephone, and it is possible to selectively call more stations than the number of push-buttons. Embodiments of the present invention shown in the drawings will be described below. FIG. 1 shows an example in which push buttons are divided into two groups, and the number of divisions is 2, 3, and 4 in current push button telephones, as will be described later. Button symbols 1, 2, 3, 0, 〓, #
The 12 symbols are divided into upper and lower groups by the dashed line in Figure 1, and when calling, one symbol from each group is used, and a total of two symbols are pressed continuously. This is the time it takes for the other party's calling buzzer to ring and for the caller to realize that he/she has been called, so it is assumed to be about 5 seconds. Then each group has 6 symbols, so
By combining 36 different signals, 36 different stations can be assigned station numbers as shown in the table below to enable selective calling. For example, if 4 in the first group and 9 in the second group are combined to create station number 16, this means that even if ``9'' is pressed after ``4'', ``4'' is pressed after ``9''. The configuration is simplified so that the same station can be selected.

[Table] In Figure 1, L1, L2, L3, and L4 represent the low frequency of the push button signal oscillator, and H1, H
2 and H3 indicate the same high frequency, and their intersecting symbols are indicated by one frequency for each high and low frequency. Therefore, the push button signal receiver outputs that it has received a signal indicating a certain symbol only when one high frequency and one low frequency exist at the same time. In current pushbutton telephones, L1 = 697Hz, L2 = 770Hz, L3 =
852Hz, L4=941Hz, H1=1209Hz, H2=1336
Hz, H3=1477Hz is selected. FIG. 2 is a configuration diagram showing an embodiment of the present invention.
UTL is the uplink telephone line (in reality, two lines are often used) DTL is the downlink telephone line, transmitter
For example, the SND is connected to the upstream line UTL, the receiver RCV is connected to the downstream line, and the handset HST is connected to both lines. When the pushbutton is operated, the transmitter SND including the pushbutton signal generator operates, and when the receiving section RCV of the other station to be called operates, the handset can be picked up and a conversation can be made. FIG. 3 is a diagram showing a specific example of the configuration of the transmitter/receiver. PB-SW
is the push button switch, SMT1 and SMT2 are the first
Symbol matrix, second symbol matrix, which selects the L line and H line so as to generate a frequency corresponding to each operated button, FF is a flip-flop, and CL is the period at which symbol signals are switched (for example, 1 to 1). 20Hz). Pushbutton switch PB-SW is the first
When two symbols are operated as a symbol and a second symbol, each line of l ₁ to l ₄ and h ₁ to h ₃ is selected in each symbol matrix SMT1 and SMT2, and for example, the output of the first symbol matrix SMT1 is pressed when the push button is pressed. Assume that a signal line connected to the signal oscillator PB-OSC is selected. Frequencies corresponding to the two selected lines L1-L4 and H1-H3 are generated, and the telephone line
Get on UTL. Next, after a time determined by the flip-flop FF and the clock pulse oscillator CL (for example, 100 msec when the clock frequency is 10 Hz), the frequency corresponding to the second symbol matrix SMT2 output is applied to the telephone line UTL. The oscillator PB-OSC alternately outputs the combined outputs of L1 to L4 and H1 to H3 corresponding to the first and second symbols at predetermined intervals (for example, every 100 msec in the above case) and sends them to other stations. At this time, two push buttons defining the first and second symbols may be pressed at the same time, or two push buttons may be pressed one after another.
Since the output of both buttons is output alternately by FF, 2
This is because it is only necessary that one button be pressed for about 5 seconds as described above. Then each oscillator PB
-The time chart of OSC output and button operation is in the 5th page.
The result will be as shown in the figure. The upper part of FIG. 5 is a diagram showing button operations, and two buttons may be operated one after another or simultaneously. The lower part of Figure 5 shows the oscillator output, and shows that if the clock frequency is 10Hz, the first symbol frequency (hatching downward to the left) and the second symbol frequency (hatching downward to the right) are sent out alternately for 100ms each. ing. Next, the lower part of Figure 3 shows the receiving section PCV, and the PB-
REC is a push-button signal receiver, and SSL is a symbol selection and identification unit. After receiving and selecting the arrival or non-arrival of the locally determined first and second symbol signals for each cycle of the transmitter's clock pulse, and identifying them, the system selects and receives them for each symbol. What is applied to the signal temporary hold circuits HLD1 and HLD2, AND indicates a logical product circuit, and BZ indicates a buzzer. Now, when the push button signal receiver PB-REC receives the push button operation symbol signal, the output lines L1 to L4 according to the given number,
One each of H1 to H3 is selected and turned on at the same time. The symbol selection identification section SSL is a circuit for connecting the output line of the push button signal receiver PB-REC and the signal temporary hold circuits HLD1 and HLD2, and is composed of, for example, two NAND circuits as shown in FIG. has been done. In Figure 4, symbol “1”
(L1, H1) and symbol "8" (L3, H2) are selectively received and identified. Next, the signal temporary hold circuits HLD1 and HLD2 are
As shown in the figure, each is composed of, for example, a monostable multivibrator. When the two symbol signals arrive alternately and are repeatedly received, the output of the AND circuit AND remains on.
When such an output from the AND circuit is obtained, the buzzer BZ is activated to indicate that a valid calling signal has arrived. The oscillation period of the monostable multivibrator corresponds to the holding time of the symbol signal, and is set to a value more than twice the clock period. The above describes the case where the push button is divided into two groups, and it is possible to selectively call up to 36 stations, but if it is necessary to call even more stations, it is divided into three groups, for example [1, 4, 7〓〕
[2, 5, 8, 0] [3, 6, 9, #]. At this time, by selecting and pressing three buttons from each group, it is possible to selectively call up to 4×4×4=64 stations, that is, up to 64 stations. Further divide it into 4 groups, for example [1, 2, 3] [4, 5, 6] [7, 8, 9] [〓,
0, #], the result is 3 x 3 x 3 x 3 = 81 ways, and up to 81 stations can be selectively called using 12 buttons, which is the maximum value. When the number of divided groups increases, it is necessary to combine a large number of symbol matrices and logical operation circuits, and to appropriately select the switching timing using clock pulses, but even if the order of symbol combinations changes, it will not affect the selective recall. Therefore, even if it is divided into multiple parts, the configuration will not become so complicated. In this way, according to the present invention, when making a selective call, the buttons of the push-button telephone are grouped and operated, and the combined operation of the push-button signal oscillator and the receiver makes it possible to easily and reliably make a selective call. Since there is no need to order each group when grouping, there is no need to provide a memory device in the operation circuit, making it simple, and the oscillator and receiver for the push button signal are a single component. Its performance is extremely stable,
Since it is inexpensive, the overall configuration is simple, operates stably, and is relatively inexpensive, making it effective when applied to temporary telephone lines in construction zones.

[Brief explanation of the drawing]

Figure 1 shows how to use the pushbutton in two parts,
An explanatory diagram of the frequency at which each symbol is obtained, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing a specific configuration example of the transmitting section and receiving section in FIG. 2, FIG. 4 3 is a diagram showing a specific circuit configuration example of the symbol selection identification section and the signal temporary hold circuit, and FIG. 5 is a time diagram showing the operation of the pushbutton in FIG. 3 and the output of the signal oscillator. It's a chat. UTL...uplink telephone line, DTL...downlink telephone line, SND...transmitter, RCV...receiver,
HST...Handset, PB-SW...Push button switch, SMT1, SMT2...Symbol matrix, PB-OSC...Push button signal oscillator, PB-
REC...Push button signal receiver, SSL...Symbol selection identification unit, HLD1, HLD2...Signal temporary hold circuit.

Claims (1)

[Scope of Claims] 1. In a selective calling method using push button telephones, in which a plurality of push button telephones are connected to the same telephone line and selective calling is performed by selectively receiving oscillation signals based on push button operations, the transmitting unit includes: is equipped with means for operating a push button signal oscillator corresponding to the operated push button,
The operating means is a means for intermittently operating the push button signal oscillators for the number of groups obtained by dividing the push buttons into a plurality of groups, and the receiving section is provided with a detection means for detecting the push button signal, and the detection means 1. A selective calling system comprising a number of reception discriminators equal to the number of reception discriminators, signal holding circuits corresponding to the reception discriminators, and a synthesis circuit for outputs of the signal holding circuits.