JPH06314245A - Data communication system - Google Patents

Abstract

(57) [Summary] [Purpose] To enable automatic correspondence even if the data transfer speed of communication data is increased due to version upgrades in POS systems and the like. [Structure] The secondary station 19 receives the synchronization data transmitted from the primary station 6 in an off-line state, and is provided with a time width measuring means 25 for detecting the time width of the synchronization data, and the time detected by the time width measuring means 25. A data communication system 2 provided with a line switching means 20 for variably setting a data transfer rate according to a width and switching an offline state to an online state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system in which a primary station and a secondary station are connected by a communication line.

[0002]

2. Description of the Related Art At present, chain stores, etc., which have stores in various locations and carry out sales operations, use a POS system to comprehensively grasp the sales situation of each store and implement sales strategies. We are planning comprehensively.

Here, the above-mentioned POS system is
For example, a large number of POS terminals, which are secondary stations, and a single store computer are installed in each of a large number of stores, and
Connected by a communication line such as AN (Local Area Network), a store computer installed in each of such a large number of stores is connected to a host computer installed in the headquarters at a PSTN (Pub).
lic Switched Telephone Network) is a structure that is connected to.

The PO of such a POS system
The S terminal is, for example, a store computer or another P terminal.
Communication data is received as binary data from an OS terminal, etc., and various kinds of work using data communication are executed by analyzing the communication data thus received at a preset data transfer rate. It is supposed to do.

Therefore, here, the PO having the above structure is used.
5 to 7 in which the S terminal is a conventional example of a secondary station.
It will be described below based on. First, P, which is this secondary station
The OS terminal 1 is a part of the POS system 2 which is a data communication system here, as illustrated in FIG. The POS system 2 connects a host computer 4 installed in one head office 3 and a store computer 6 which is a primary station installed in each of a number of stores 5 with a PSTN 7 which is a communication line. The store computer 6 installed in an office (not shown) in the store 5 and the POS terminal 1 which is a secondary station installed in each of a number of sales floors (not shown) are loop type. It has a structure in which it is connected by a LAN 8 which is a communication line.

The POS terminal 1 of the POS system 2 has input terminals 9 and 10 and output terminals 11 and 12 having different polarities of the LAN 8 as illustrated in FIG.
Are connected to an electromagnetic relay 13 which is a data receiving means. The electromagnetic relay 13 is connected to an SCC (Serial Communication Controll) via a receiver 14 and a driver 15.
er) 16 is connected. A transmission / reception clock 17 and a CPU (not shown) are connected to the SCC 16, and a relay controller 18 connected to the CPU is connected to the electromagnetic relay 13.

Therefore, in the POS terminal 1, the SCC 16 receives the communication data consisting of binary data from the LAN 8 through the electromagnetic relay 13, and at this time, the SCC 16 generates the transmission / reception clock 17 for the communication data. I am trying to receive at the data transfer rate. In this POS terminal 1, the CPU
Controls the switching operation of the electromagnetic relay 13 by the relay controller 18, so that the terminals 9 to 12 are
Is connected to the SCC 16, and an offline state in which the terminals 9 to 12 are directly connected to the through is set to be switchable.

Conventionally, it has been necessary to manually switch the data transfer rate to a value suitable for the system by using a dip switch or the like in advance.

[0009]

In the POS terminal 1 described above, the binary data transmitted from the external store computer 6 or the POS terminal 1 located at a higher level is received at the preset data transfer rate, It is designed to perform various types of data communication.

Here, in the POS system 2 as described above, the data transfer speed of communication data may be increased, for example, to upgrade the version of the store computer 6. Therefore, in such a case, the same store 5
It is necessary to reset the data transfer rates of all the POS terminals 1 installed in. This is not preferable because the work is complicated and requires a large cost.

Further, in the above-mentioned POS system 2, since the store computer 6 and a large number of POS terminals 1 and the like are performing data communication at the same data transfer rate, a new POS system is added to such a POS system 2. When adding the terminal 1, it is necessary to synchronize the data transfer rates. However, this requires measuring the data transfer speed of the operating POS system 2 and setting it in the POS terminal 1 to be added, which is not desirable because the work is complicated and the cost is also high.

[0012]

[MEANS FOR SOLVING THE PROBLEMS] A primary station and a secondary station having a synchronous data transmitting means for transmitting synchronous data composed of binary-coded 0 data and a predetermined number of consecutive binary-coded 1 data as a start signal via a communication line. In the connected data communication system, when the secondary station receives the synchronization data in an offline state, a time width measuring means for measuring the time width of continuous binary 1 data based on the oscillation clock of the own station,
It has line switching means for setting the data transfer rate corresponding to the time width measured by the time width measuring means and switching the own station from the offline state to the online state.

[0013]

When the time width measuring means of the secondary station receives the synchronous data in the off-line state, it measures the time width of continuous binary 1 data based on the oscillation clock of its own station, and the line switching means of this secondary station By setting the data transfer rate corresponding to the time width measured by the time width measuring means and switching the own station from the offline state to the online state, for example, data transfer of communication data for version upgrade of the data communication system, etc. Even if the speed is increased, it is possible to respond automatically without the need for setting parts, and even when a secondary station is newly added to the active data communication system, There is no need to measure and reset the data transfer rate in advance.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As for the POS terminal 19 illustrated as an example of the secondary station, the same parts as those of the POS terminal 1 and the POS system 2 described above as a conventional example have the same names and reference numerals. Detailed description is omitted. First, this secondary station, POS Terminal 1
Is a POS system 2 which is also a data communication system
Is connected to the store computer 6 as a primary station and another POS terminal 19 by a loop type LAN 8.

As shown in FIG. 1, the POS terminal 19 includes an electromagnetic relay 13 to which terminals 9 to 12 of the LAN 8 are connected, a receiver 14, and a driver 1.
5 is connected to the SCC 16 via
A CPU (not shown) and a clock unit 20 which is a line switching unit are connected to 16. Here, in the clock unit 20, the frequency divider 22 is connected to the output terminal of the system clock 21 in which the data transfer rate is fixedly set in advance, and the frequency divider 22 is connected to the four output terminals which are conducted to the SCC 16. The structure is such that the buffer circuit 24 is connected to the control terminal of the provided data selector 23. The output terminal of the rate detection circuit 25 is connected to the input terminal of the buffer circuit 24 of the clock unit 20, and a predetermined data transfer rate is fixed in advance to the two input terminals of the rate detection circuit 25. The detection clock 26, which is set to be specific, is connected to one input terminal 9 of the LAN 8.

More specifically, this POS terminal 19
In the rate detection circuit 25 of FIG. 2, two input terminals to which the detection clock 26 and the input terminal 9 are connected are connected to a counter circuit 28 via an AND gate 27 as illustrated in FIG. The four output terminals of the circuit 28 are combined by the AND gate 29 and are connected to the buffer circuit 31 together with one output terminal provided with the latch circuit 30. A reset circuit 33 is connected to one input terminal of the AND gate 32 whose output terminal is connected to the control terminal of the buffer circuit 31, the counter circuit 28, and the latch circuit 30, and the reset circuit 33.
One input terminal 9 of the LAN 8 connected to the inverter circuit 34 is connected to the other input terminal of the AND gate 32 and the buffer circuit 35.

Therefore, in this POS terminal 19,
The four output terminals of the buffer circuit 31 of the rate detection circuit 25 are the buffer circuit 24 of the clock unit 20.
Are connected to the four input terminals by a data bus. Further, in the POS terminal 19, an interrupt port connected to the buffer circuit 35 of the rate detection circuit 25, a rate detection port connected to one input terminal of the AND gate 32, and the clock unit 20. The clock switching port connected to the control terminal of the buffer circuit 24 is connected to the control bus of the CPU.

In the POS terminal 19, the SCC 16 receives communication data composed of binary data from the LAN 8 via the electromagnetic relay 13, and at this time, the SCC 16 receives the communication data by the clock unit 20. It receives at the data transfer rate that occurs. In the POS terminal 19, the CPU controls the switching operation of the electromagnetic relay 13 by the relay controller 18, so that the terminals 9 to 12 are connected to the SCC 16 in an online state and the terminals 9 to 12 are connected. Is set to be switchable between the offline state in which is directly connected to the through.

Then, the store computer 6 of the POS system 2 transmits synchronous data composed of binary 0 data and a predetermined number of consecutive binary 1 data as a start signal at the start of data communication. (Not shown) is provided by a CPU (not shown) or the like.

Further, in the POS terminal 19 of the POS system 2, when the synchronous data is received in the offline state, the time width measuring means for measuring the time width of continuous binary 1 data based on the oscillation clock of the own station is the above-mentioned. It is formed by the rate detection circuit 25 and the CPU.
The line switching means for setting the data transfer rate corresponding to the time width measured by the time width measuring means such as PU and switching the own station from the offline state to the online state is the S
It is formed of the CC 16, the clock unit 20, the CPU, and the like.

In the POS terminal 19, for example, the rate detection circuit 25 detects the time width of the communication data received by the initial setting immediately after the start-up, and the clock corresponding to the time width detected by the rate detection circuit 25. Unit 20
Is designed to variably set the data transfer rate. By doing this, this POS terminal 19
For example, even if the data transfer speed of the communication data of the store computer 6 is increased due to a version upgrade or the like, it can be automatically coped with without setting manually by a dip switch or the like. New POS terminal 19 in POS system 2
Even in the case of adding more, since it is not necessary to measure and reset the data transfer rate in advance, the productivity can be improved.

Therefore, such a POS terminal 19
The processing operation will be described in detail below with reference to FIGS. 3 and 4.
First, in the POS terminal 19, as shown in FIG. 4, the CPU controls the switching operation of the electromagnetic relay 13 by the relay controller 18 in the initial setting immediately after the start-up, so that the terminals 9 to 12 are directly connected to the offline. It is in a state. Therefore, in this state, when the communication data received from the one input terminal 9 of the LAN 8 by the POS terminal 19 becomes "H", the rate detection circuit 25 detects the clock 2 while the communication data is "H".
The counter circuit 28 counts the number of 6 clock pulses. Therefore, when the communication data received from the input terminal 9 of the LAN 8 becomes "L" in such a state, the CPU reads the count data held in the counter circuit 28.

At this time, the data transfer rate of the clock pulse of the detection clock 26 is preset to a fraction of the data transfer rate of the communication data as shown in FIG. The count data held in 28 is "4 pulses" in the case shown in (a).
Here, if the count data held in the counter circuit 28 exceeds a reference value such as "16 pulses" as in the case shown in (b), it is determined that this is an overflow and the latch circuit 30 holds it. Has become.

In the above-mentioned state, C can be input to the buffer circuit 35 for a preset detection time.
Due to the iNT interrupt of the PU, the CPU causes the AND gate 32
When the rate detection port connected to is activated, sampling of the count data is performed, and after the sampling is completed, the counter circuit 28 and the latch circuit 30 are reset by the reset circuit 33, and when the pulse number overflows or underflows, It waits until the communication data becomes "H".

Then, the CPU, which has determined the time width as described above, determines the data transfer rate corresponding to the determined time width, and sets the data selector 23 of the clock unit 20 to realize this data transfer rate. Buffer circuit 2
Control with 4. The data selector 23 selectively transmits one of the clock pulses obtained by dividing the clock pulse of the system clock 21 by the frequency divider 22 in four stages to the SCC 16. By doing this, this POS terminal 1
In 9, the data transfer rate of the SCC 16 is automatically synchronized with the data transfer rate of communication data.
The POS terminal 19 which has been completed as the initial setting as described above has the terminal 9 when the CPU controls the switching operation of the electromagnetic relay 13 by the relay controller 18.
Various data communications will be started by setting the above-mentioned elements 12 to 12 connected to the SCC 16 in an online state.

[0026]

As described above, according to the present invention, a primary station and a secondary station having synchronous data transmitting means for transmitting synchronous data composed of binary 0 data and a predetermined number of continuous binary 1 data as a start signal are provided. In a data communication system in which the secondary station is connected by a communication line, when the secondary station receives the synchronization data in an offline state, a time width measuring means for measuring the time width of continuous binary 1 data based on the oscillation clock of the own station. By having a line switching means for setting the data transfer rate corresponding to the time width measured by the time width measuring means and switching the own station from the offline state to the online state, for example, the version upgrade of the data communication system, etc. Therefore, even if the data transfer speed is increased, it is possible to automatically respond without the need for setting parts, In addition, even when a new secondary station is added to an operating data communication system, it is not necessary to measure and set the data transfer rate in advance, which can contribute to labor saving and cost saving. It has the effect of being able to do so.

[Brief description of drawings]

FIG. 1 is a circuit diagram illustrating a main part of a POS terminal which is an embodiment of a secondary station of the present invention.

FIG. 2 is a circuit diagram illustrating an internal structure of a rate detection circuit which is a time width measuring means.

FIG. 3 is a time chart exemplifying waveforms of communication data and a detection clock.

FIG. 4 is a flowchart illustrating a processing operation for setting a data transfer rate.

FIG. 5 is a schematic diagram illustrating the overall structure of a POS system including a POS terminal, which is a conventional example of a secondary station.

FIG. 6 is a circuit diagram illustrating a main part of a POS terminal.

FIG. 7 is a time chart for measuring a waveform of communication data.

[Explanation of symbols]

 1 Secondary station 2 Data communication system 6 Primary station 8 Communication line 20 Line switching means 25 Time width measuring means

Claims (1)

[Claims] 1. Data communication in which a primary station and a secondary station are connected by a communication line and which has a synchronous data transmitting means for transmitting synchronous data consisting of binary 0 data and a predetermined number of consecutive binary 1 data as a start signal. In the system, when the secondary station receives the synchronous data in an offline state, the time width measuring means for measuring the time width of continuous binary 1 data based on the oscillation clock of the own station, and the time width measuring means measure the time width. A data communication system comprising: a line switching means for setting a data transfer rate corresponding to the time width and switching the own station from an offline state to an online state.