JPH0320117B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a data processing circuit,
In particular, but not exclusively, it relates to such a circuit for use in a telephone device to receive bursts of data pulses from a data processing device.

[Prior Art] In a telephone system consisting of a central control unit and a large number of associated telephone terminals, the telephone terminals are often idle for long periods of time without any calls. However, the central controller is required to react quickly to any changes occurring at any of the telephone terminals.

SUMMARY OF THE INVENTION It is therefore desirable to continuously monitor each telephone terminal and to send data regarding changes occurring at that telephone terminal to a central control unit within a reasonable period of time.
Additionally, once the telephone system responds to pushbutton operations to establish the necessary communication paths between telephone terminals, the controller must also ensure that the control device responds to operations that involve pressing the pushbutton for only a short period of time.

It is therefore an object of the present invention to detect received pulse bursts quickly and accurately.

[Means for Solving the Problems] A data processing circuit of the present invention performs data processing for receiving a pulse burst consisting of a prefix pulse and a plurality of data pulses that follow this pulse and have a pulse width shorter than this pulse. the circuit, wherein the input signal is sampled during each burst at a first rate that is slower than the transmission rate of the data pulses and, upon detection of a prefix pulse, faster than the transmission rate of the data pulses; The data is sampled at a second rate, and when a first data pulse of the data pulses is detected, it is sampled at a third rate, which is the same as the transmission rate of the data pulses.

A first periodic rate is substantially less than the pulse transmission rate, a second periodic rate is substantially faster than the transmission rate, and a third periodic rate is substantially the same as the transmission rate. It is preferable that there be.

According to the present invention, it is possible to detect received pulse bursts quickly and accurately with the above-described configuration and operation.

[Operations and Examples] An example of a telephone device including a data processing device according to the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, a telephone system is shown comprising a central control unit 1, a line concentrator 2 and three telephone terminals 3, 4 and 5. Each telephone terminal 3, 4
and 5 have a data processing circuit or data interface 6, a telephone 7, a display panel 8 and a keypad 9. Each telephone set 7 is connected to a trunk line 10 via a subscriber line 11 and a line concentrator 2 under the control of the central control unit 1, respectively.

Referring also to FIG. 2, each data interface 6 has a microprocessor 13 whose operating speed is determined by a frequency controller 14, an input buffer circuit 1
5 and an output buffer circuit 16.

The microprocessor 13 connects the central controller 1 to each data transmission path 12 and input buffer circuit 15.
Receive data via. Microprocessor 13 uses the received data to determine which of the set of lamps or light emitting diodes 21-28, if any, should be lit. An audible alarm device (not shown) can also be controlled in a similar manner.

This microprocessor also detects whether any of the buttons or switch contacts 41 to 48 on the keypad 9 have been activated, and stores data regarding the operation of these buttons in an internal memory (not shown). . After receiving the data from the central control device 1, data regarding button operations is transferred to the central control device 1 via the output buffer circuit 16 and the data transmission line 12. In fact, one of the contacts 41 to 48 may be a contact of a corresponding telephone 7 switch.

When no data is being exchanged between the central control unit 1 and the data interface 6, the microprocessor 13 scans the contacts 41 to 48 of the keypad 9 to determine which of these buttons, if any, is activated. Determine whether That is, microprocessor 13 sequentially applies a signal to each of outputs 50-53 and examines inputs 17 and 18 for returning signals. For example, if only the corresponding button of contact 42 is operated, the signal at output 52 will appear only at input 17.
In this case the signals at outputs 50, 51 and 53 do not appear at either input 17 or 18. Upon completion of scanning keypad 9, microprocessor 13 samples input 19 to determine whether it is currently receiving a data burst from central controller 1. This is indicated by a prefix pulse, which represents a change in the binary state of input 19 and precedes this data burst. In the absence of this prefix, microprocessor 13 returns to scanning keypad 9 as described above.

When a prefix pulse is present at input 19, microprocessor 13 stops scanning keypad 9 so that a further change in the binary state of input 19 signals the end of the prefix and the beginning of the start bit of the input data burst. Iteratively samples input 19 until it represents . Here, microprocessor 13 varies the rate at which it samples input 19 to sample this input at substantially the bit rate of the input data burst.

The microprocessor 13 of each data interface 6 operates under the control of its respective internal clock (not shown), which clock is controlled by a respective frequency controller 14. Each clock of each microprocessor 13 is
The sampling of each input 19 when receiving data from the central controller 1 is arranged to occur at substantially the same rate as the bit transmission rate by the central controller 1. This speed is referred to herein as the bit speed. The time required by the central controller 1 to transmit one data pulse is called a bit period.

Before microprocessor 13 takes the first sample of its input data stream, ie, detects the end of the prefix pulse, there is a delay of half a bit period. Since microprocessor 13 is sampling input 19 substantially at its bit rate, this ensures that each bit of the input data burst is sampled substantially only half of the time during each bit period. Become.

Upon receiving the input data burst, the microprocessor 13 delays by approximately two bit periods and then forwards the accumulated data regarding the operation of the contacts 41 to 48 to the central controller 1.

After completing the transfer of the stored data, the microprocessor 13 uses this data received from the central controller 1 to turn on or off designated lamps on the display panel 8, or to set off an audible alarm (not shown). ) to start or stop the sound.

The signaling system between the central control unit 1 and each of the telephone terminals 3, 4 and 5 will now be described in detail with reference to FIG.

The central control unit 1 sequentially scans the data transmission paths 12 of each of the telephone terminals 3, 4 and 5. When the central control unit 1 starts scanning the data transmission line 12 of the telephone terminal 3, for example, a signal 60 representing a binary "1" is thereby applied to the data transmission line 12. This signal 60, referred to herein as a prefix pulse, is held by the central controller 1 for three bit periods. As previously mentioned, the data interface 6 of the telephone terminal 3 initially samples the data transmission line 12 at a low sampling rate, e.g. The sample points made at the low sample rate are represented by arrows 68 in FIG.

Since the prefix 60 is held in the data transmission path 12 for 3 bit periods, at least 1
Prefix 6 is generated after 68 sample points are generated.
0 must be removed. When data interface 6 detects prefix 60, the sampling rate increases to six times the bit rate, as indicated by sample point 69.

When three bit periods have elapsed, the central controller 1 applies a binary "0" signal to the data transmission line 12.
This signal, called start bit 61, is held by central controller 1 for one bit period. Changes in the binary state of the data transmission line 12 are detected by the data interface 6 within 1/6 of one bit period, and the interface 6 then changes its sampling rate substantially as indicated by the sample point 70. Change the bit speed to .

At the end of the start bit 61, the central controller 1 sequentially applies a binary data signal 62 to the data transmission line 12, representing eight data bits.
Data signal 62 is received and stored by data interface 6 as previously described.

The central control unit 1 must now receive data relating to the operation of the contacts 41 to 48 of the keypad 9 of the telephone terminal 3. The transmission of this data begins after period 20, which is approximately 2 bit periods. During this period 20, the central controller 1
The data transmission line 12 is repeatedly sampled at a rate of about 6 times per bit period, as indicated by 1. Data interface 6 represents a binary "1". A signal 64 is applied to the data line 12 which indicates to the central controller 1 the beginning of a burst of data pulses representing stored data relating to the operation of the buttons on the keypad 9. Central controller 1 detects signal 64 and then changes its sampling rate to a bit rate as shown at sample point 72. Upon completion of the start signal 64, the data interface 6 applies a binary signal 65 to the data transmission line 12 representing eight data bits relating to the operation of the buttons on the keypad 9. Signal 65 is central control unit 1
received and stored by.

The central controller 1 then delays for one bit period 66 and then starts scanning each data transmission line 12 of the next telephone terminal 4;
2 on the data transmission path before each data burst of
This is done by providing a binary ``1'' signal 67.

Each data transmission path 12 of telephone terminals 3, 4 and 5
If all are scanned using the method described above,
In response to the received data, the central control unit 1 establishes a connection between one of the telephone terminals 3, 4 and 5 and the trunk line 10 in the line concentrator 2, for example. During this period (although this does not necessarily have to be a fixed period), the data transmission line 12 is not scanned.

When the central controller 1 has completed all its tasks required by the data received from the telephone terminals 3, 4 and 5, it repeats the scanning sequence described above.

For example, the connection from the telephone terminal 3 to the trunk line 10 is performed as follows. This indicates that a connection to the trunk line 10 is requested by lifting the handset of the telephone 7 and operating the buttons on each keypad 9. These handset-up and button-actuating actions are detected by each data interface 6, which, when scanned, transmits data relating to these actions to the central control unit 1. All telephone terminals 3, 4 and 5
When the scanning is completed, the central control unit 1 uses the line concentrator 2 to establish a connection between the trunk line 10 and each communication path 11 of the telephone set 7 of the telephone terminal 3. The dial impulse and transmission of the call are then performed in a known manner.

As the telephone terminals 3, 4 and 5 are sequentially scanned, the central control unit 1 sends data to the respective data interface 6 of each telephone terminal indicating to the data interface 6 that the trunk line 10 is in use. Upon receiving this data, the data interface 6 lights up the lamp on the corresponding display panel 8 to indicate that the relay point 10 is in use.

When the handset of the telephone 3 is put back on, it is detected by the corresponding data interface 6 and sends this information via the transmission line 12 to the central control unit 1 in the manner already described. When the scanning of each data transmission path 12 is completed, the central control device 1 causes the line concentrator 2 to restore the connection between the trunk line 10 and each communication path 11 of the telephone terminal 3. Next, by scanning the data transmission line 12, the central control unit 1 sends data to the data interface 6 of each telephone terminal 3, 4, and 5, and turns off the lamp indicating that the trunk line 10 is in use. let

For example, by using other buttons on keypad 9, you can request a connection to one of the other telephone terminals;
You may also request that incoming calls not be connected to the telephone terminal associated with that keypad.

Other lamps on the display panel 8 may be used to indicate which of the telephones 7 is in use or to indicate which of the telephone terminals 3, 4 and 5 an incoming call is directed to that display panel. It may also be possible to display a message indicating that the transfer is being automatically transferred to the selected telephone.

In other larger systems (not shown) similar to the apparatus described above, there may be a large number of telephone terminals. In that case, the scanning cycle of the central control unit 1 becomes long; for example, in a system including 10 such telephone terminals, the time required to scan all the data transmission lines 12 is on the order of 37.5 milliseconds. There is a period on the order of about 25 milliseconds between scanning the last of the data transmission paths and scanning the first of the data transmission paths.
Meanwhile, the central control unit 1 carries out its control functions. Therefore, for example, a period on the order of 62.5 milliseconds elapses between scanning the data transmission line 12 of the telephone terminal 3 once and scanning it again.

This 62.5 millisecond period is longer than the minimum movement and recovery time of the button contacts 41-48 of the keypad 9;
It is on the order of 40 milliseconds. Therefore, if the data relating to the contacts 41 to 48 are sent directly to the central control unit 1, the minimum time for operating one button of the keypad 9 will elapse.

The microprocessor 13 has contacts 41 to 4.
These contacts are configured to be sampled at intervals much shorter than the minimum operation and recovery times of 8. The microprocessor 13 has its output 50
By sequentially applying signals to contacts 41-53, it is determined which, if any, of contacts 41-48 are closed by examining their inputs 17 and 18. For example, if only contact 44 is closed, the signal provided by microprocessor 13 at its output 50 will appear only at input 17. In this case the signals at outputs 51, 52 and 53 do not appear at any of inputs 17 and 18. Upon detecting the closure of a set of contacts, microprocessor 13 sets each bit in an internal memory (not shown) associated with the set of contacts detected as closed.

Microprocessor 13 closes contact 4 until a change in the binary state of input 19 indicates receipt of a start signal.
Further scan for 1 to 48 state changes. This start signal precedes the transmission of a data burst from the central controller 1.

If the microprocessor detects another change in the state of a set of contacts before it has transferred data regarding the first change in the state of that set of contacts, it will not be able to wait until it has transferred the data to the central controller 1. It does not modify each bit in its internal memory. Data regarding such further changes in the state of the contact set is transferred to the central control unit 1 as each data transmission line 12 is scanned one after the other.

[Effects of the Invention] To summarize the present invention, a central processor controlled telephone system includes a telephone set having respective data circuits. Each data circuit scans stored data regarding the state of each keypad and its buttons. Each stored data is sent to the central processor in response to requests from the central processor. The data circuitry scans the keypad buttons, which in turn scan the data inputs connected to the central processor. Upon detection of a prefix pulse from the central processor, the data circuit repeatedly samples this data input until a start pulse is detected. When a start pulse is detected, the data circuit scans the data input at that bit rate. If one button on the keypad changes state more than once between each request from the processor, the respective data for the next change will not be modified by this data circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the apparatus of the present invention, FIG.
The figure shows a part of Fig. 1 in detail, and Fig. 3 shows the details of Fig. 1.
FIG. 3 is a diagram showing waveforms illustrating the operation of the data interface and central control unit shown in the figure. Explanation of symbols for main parts, 1...Central control unit, 6
...Data interface, 8...Display panel, 9...Keypad, 12...Data transmission line,
13...Microprocessor, 14...Frequency control device, 15...Input buffer circuit, 16...Output buffer circuit.

Claims (1)

[Claims] 1. A data processing circuit for receiving a pulse burst consisting of a prefix pulse and a plurality of data pulses that follow this pulse and have a pulse width shorter than this pulse, wherein each input signal is sampled at a first rate slower than the transmission rate of the data pulses during the burst;
When detecting a prefix pulse, sampling is performed at a second rate faster than the transmission rate of the data pulse, and when detecting a first data pulse of the data pulses, the sampling rate is faster than the transmission rate of the data pulse. Data processing circuitry sampled at the same third rate.