JP2898025B2 - I / O terminal - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output terminal for connecting information processing devices to each other via a cable, and more particularly to input / output of a busy signal exchanged between the information processing devices. The present invention relates to an input / output terminal that can automatically detect terminals.

[Related Art] For example, data transmission / reception between computers or between a computer and a printer or a CRT display device is performed via a cable by converting parallel data into serial data. Then, there is an RS-232C or RS-232D standard as a standard that defines an interface (boundary condition) when connecting each device.

The RS-232C standard is originally a standard for connecting, for example, a terminal device and a computer via a modem and a cable. However, in recent years, as shown in FIG. 4, in many cases, the modem is omitted and the terminal device 1 and the computer 2 are directly connected by the cable 3.

In this case, female connectors 6a and 7a having a shape specified by the RS-232C standard are attached to the input / output terminals 4 and 5 provided in the terminal device 1 and the computer 2, respectively. Male connectors 6b and 7b are attached to the three sides.

As shown in FIG. 5, connectors 6a and 7a have
There are provided twenty-five terminals 8 assigned with respective pin numbers of 5, and the types of signals input / output to / from each terminal 8 are defined. However, there is a terminal whose signal type is not yet defined among the 25 terminals 8. For example, as shown in FIG.
Terminal is a safety ground (F
G) terminal, terminal # 2 is a terminal for outputting transmission data (SD), terminal # 3 is a terminal for receiving reception data (RD), and terminal # 4 is a transmission request (RS) signal. # 5 is a terminal to which a transmission enable (CS) signal is input,..., # 7 are signal ground (SG) terminals other than the FG, and # 20 is a terminal device. A terminal 1 outputs a terminal ready (ER) signal indicating a data receivable state.

Therefore, data is actually input / output only to the # 2 transmission data (SD) terminal and the # 3 reception data (RD) terminal. Each terminal other than the ground terminals of the two FGs and SGs is It is used for transmitting and receiving various control signals for smoothly performing data transmission and reception between the terminal device 1 and the computer 2.

However, various combinations of the terminal device 1 and the computer 2 are conceivable, and the data processing speeds of the terminal device 1 and the computer 2 may greatly differ. Also, the data processing speed of the terminal device 1 differs naturally between the case where the terminal device 1 is a CRT display device and the case where the terminal device 1 is a printer. Further, even when the terminal device 1 is a data input device for inputting data to the computer 2, the input speed for inputting data to the computer 2 differs depending on the type. Also, in the computer 2, the processing speed is different if the processing content in the data processing is different. Therefore, when one of them is processing data, a busy signal is sent to the other so as not to accept a new data input.

However, since the RS-232C standard is originally used for an interface of data communication using a modem, transmission of a busy signal is not considered. Therefore, in general, when a busy signal is transmitted to the other processor, the signal level of each signal is inverted so that the other party is notified that it is busy.

[Problems to be Solved by the Invention] However, when a busy signal is transmitted to the other party by the above-described method, if the signal level of any input terminal is inverted for the receiving side of the busy signal, the other party becomes busy. It is necessary to check beforehand whether the state is in a state, and connect with a cable.

However, the signal level of which signal terminal is inverted as a busy signal is not standardized, and often differs depending on the type of each terminal device 1 and the type of each computer 2. Therefore, when the terminal device 1 is connected to the computer 2 or when the terminal devices 1 are connected to each other, the terminal 1 is connected to the output terminal of the busy signal of the other party, that is, the input / output terminal of the main device. It is necessary to search for an input terminal in the cable connector and wire the connection cable.

Also, it is necessary for the other party to check which input terminal receives the busy signal output from the main unit. That is, it is necessary for the main unit to check which output terminal of the main unit should transmit the busy signal, and wire the cable.

However, since the busy signal is not output during the period when each device is executing the data processing normally, it is very necessary to check the input terminal and the output terminal to which the busy signal is input / output, and to make a cable each time. It took time and effort. Therefore, when each device is newly connected or the connection is changed, the adjustment work until it actually operates becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and a bus signal is forcibly transmitted from an external device and a main unit to check a response from the external device, thereby easily inputting / outputting a busy signal. Terminals can be specified, and when processing devices are connected to each other using a cable, adjustment work related to the connection can be performed in a short time, correct data transmission / reception can be started immediately, and even if the input / output terminals of busy signals are unknown. It is an object of the present invention to provide an input / output terminal that can easily change the connection between processing devices.

[Means for Solving the Problems] In order to solve the above problems, the present invention transmits transmission data and various control signals output from a main unit to an external device of a data transmission / reception destination via output terminals of a connector and a cable. At the same time, at an input / output terminal for transmitting received data and various control signals input from the external device through the respective input terminals of the cable and the connector to the main unit, data is transmitted from the external device in response to a continuous data transmission request. A signal level inverting means for sequentially inverting each signal level of each output terminal during a continuous input period; and a method for stopping data input from an external device in response to the signal level inversion of each output terminal. A busy signal output terminal detecting means for determining the output terminal whose signal level has been inverted as a busy signal output terminal from the main unit, and an external device A signal level detecting means for detecting a signal level of each input terminal during a period in which a processing request having a large processing capacity is continuously transmitted; and an input terminal for which signal level inversion is detected by the signal level detecting means is connected to an external device. And a busy signal input terminal detecting means for determining a busy signal input terminal from the side.

[Operation] In the input / output terminal configured as described above,
When checking which output terminal should be used to send a busy signal from the main unit to an external device, first, a continuous data transmission request is sent to the external device to cause the external device to continuously send data. In this state, the signal level of the output terminal is sequentially inverted, and when the data input from the external device is stopped at the time of the inversion, it can be considered that the output terminal whose signal level has been inverted has transmitted the busy signal. Output terminal.

On the other hand, when checking which input terminal of the connector of the input / output terminal receives the busy signal output from the external device, a processing request exceeding the processing capacity of the external device is continuously sent to the external device. . Then, the signal level of each input terminal is monitored during the transmission period. The external device outputs a busy signal when it cannot satisfy the processing request. Therefore, the input terminal whose signal level is inverted can be specified as the input terminal of the busy signal.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a terminal device 21 such as a printer or a CRT display device in which the input / output terminal of the embodiment is incorporated, and a terminal device 2 such as this.
FIG. 1 is a schematic diagram showing an external device 23 composed of a host computer connected to a 1 via a cable 22 having the RS-232C standard.

At both ends of the cable 22, connectors 24 and 25 arranged in accordance with the aforementioned RS-232C standard are connected, and one of the connectors 24 is connected to an input / output terminal 26 in the terminal device 21. The other connector 25 has an external device 23
I / O terminal 27 is connected. A main device 28 is connected to an input / output terminal 26 in the terminal device 21.

In the input / output terminal 26, the # 1 security ground (FG) terminal of the connector 24 and the signal source ground (S
G) The terminals pass through the input / output terminals 26 and are connected to the frame of the main unit 28 and the signal ground, respectively.

# 2, # 4, # 20 output terminals 29a, 29b, 29c of connector 24
, An SD signal, an RS signal, and an ER signal are applied from the main unit 28 via the drivers 30a, 30b, and 30c, respectively.

The input terminals 31a, 31b, 31c, 31d, and 31e of # 3, # 5, # 6, # 8, and # 22 of the connector 24 are connected to the external device 23 from the R side, respectively.
D signal, CS signal, DR signal, CD signal, CI signal are input, and the input signals are receivers 32a, 32b, 32c, 32d, 32, respectively.
It is input to the main unit 28 via e.

The input terminals of each driver 30a, 30b, 30c are connected to each output port Q1, Q2, Q3 of the output interface 33, and the output terminal of each receiver 32a, 32b, 32c, 32d, 32e is connected to each input port of the input interface 34. Ports P1, P2, P3, P4, and P5 are connected.

The output interface 33 and the input interface
Reference numeral 34 is connected to a CPU (central processing unit) 36 via a bus line 35. The CPU 36, in addition to the output interface 33 and the input interface 34 via the bus line 35,
ROM 37 for storing control programs, RAM 38 for storing various variable data such as output pointer and input pointer, operation panel
Control 39. That is, the CPU 36, the ROM 37, the RAM 38, the output interface 33, and the input interface 34 constitute a control unit 40 that controls input / output signals to the input / output terminals 29a to 31e of the connector 24.

Then, the CPU 36 of the control unit 40 incorporated in the input / output terminal 26 detects the output terminal of the busy signal output from the main unit 28 and the external device 23 according to the flowcharts of FIGS. The program is configured to execute a process of detecting the input terminal of the transmitted busy signal.

When connecting the terminal device 21 and the external device 23, the connectors 24 and 25 of the cable 22 are connected to the input / output terminals 26 and 27 of the terminal device 21 and the external device 23, respectively. Then, the power to each of the devices 21 and 23 and each of the terminals 26 and 27 is turned on to bring them into an operating state.

In this state, the operation panel 39 of the control unit 40 is operated to input a detection command of the busy signal output terminal. Then, the CP
U36 starts the output terminal detection processing of FIG. When the flowchart is started, a data continuous transmission request signal is sent from the output port Q1 of the output interface 33 to the driver 30a in S (step) 1. Then, the data continuous transmission request signal is transmitted to the # 2 transmission data (SD) terminal 29a and the cable 22.
Is input to the # 3 received data (RD) terminal of the connector 25 of the external device 23 composed of the host computer via the.

The external device 23 that has received the data continuous transmission request signal is connected to the terminal device via the # 2 transmission data (SD) terminal of the connector 25.
The predetermined data is continuously transmitted to the # 3 reception data (RD) terminal 31a of the connector 24 on the 21 side.

When this continuous data is received via the receiver 32a and the input port P1 of the input interface 34, the output pointer Q of the RAM 38 is set to the initial value 1 in S2. Next, in S3, the output signal level of the Q-th output port designated by the output pointer Q of the output interface 33 is inverted. Therefore, the signal level of one output terminal 29a to 29c connected to this output port is inverted. In S4, in response to the signal level inversion, it is checked whether or not continuous data input to the # 3 reception data (RD) terminal 31a has stopped.

If the data input is not stopped, the Q-th output terminal is not a busy signal output terminal, so the signal level of the output terminal is returned to its original level, and 1 is added to the output pointer Q in S5.
When it is confirmed in S6 that the output pointer Q after addition does not exceed the maximum value 3, the process returns to S3, inverts the output signal level of the Qth output port specified by the output pointer Q after addition, and returns the received data. (RD) It is determined whether or not the data input to the terminal 31a stops.

When continuous data input stops in S4, the external device 23
However, the signal level inversion in S3 is performed by the main unit of the terminal device 21.
By judging that the busy signal has been input from 28, it can be judged that continuous data transmission has been stopped. Therefore, in S7, the output terminal corresponding to the output port designated by the output pointer Q is transmitted to the main unit 28 as the output terminal of the busy signal.
The main unit 28 stores the output terminal in the storage unit as a busy signal output terminal.

Thereafter, in S8, the continuous data transmission request signal to the external device 23 is released. If the output pointer Q after the addition exceeds the maximum value 3 in S6, the external device 23 determines that the busy signal is not accepted, and outputs the busy signal no information to the main device 28.
Send to

Next, when a search command for a busy signal input terminal is input from the operation panel 39, the CPU 36 executes the flow chart of FIG.

When the flowchart starts, the input pointer P of the RAM 38 is determined in S9.
Is set to the initial value 1. Next, in S10, for example, a processing request command accompanied by a mechanical operation is continuously transmitted to the external device 23 via the output interface 33 and the driver 30a. The processing request command accompanied by the mechanical operation may be, for example, a print output command or a paper feed command in a printer connected to the external device 23. In addition, a processing request command for executing a large amount of data processing in a short time such as image processing may be used. In other words, any processing request having a processing capacity that the processing cannot keep up with the processing requests sequentially input on the external device 23 side may be used. Therefore, the external device 23
Should output a busy signal to the terminal device 21.

Then, in S11, the signal level of the P-th input port designated by the input pointer P is monitored. If the signal level of the input port does not change in S12, the input terminal connected to this input port is not a busy signal input terminal, so the process proceeds to S13, where 1 is added to the input pointer P. When it is confirmed in S14 that the input pointer P after the addition does not exceed the maximum value 5, the process returns to S10 and sends the above-mentioned processing request command to the external device 23 again.

Then, in S12, when the signal level of the P-th input port designated by the input pointer P is inverted, the input terminal corresponding to the input port becomes the input terminal on the terminal device 21 side of the busy signal output from the external device 23. Is determined to be. Then, in S15, the corresponding input terminal is transmitted to main device 28 as a busy signal input terminal. The main unit 28 stores the input terminal in the storage unit as a busy signal input terminal.

If the input pointer P after the addition exceeds the maximum value 5 in S14, the external device 23 determines that the busy signal is not to be output, and transmits the no busy signal information to the main device 28.

With the input / output terminal configured in this manner, for example, an output terminal of a busy signal output from the external device 23 on the other end of the connection, that is, an input terminal 31a of the terminal device 21 side
Even if the input terminal through which the external device 23 receives a busy signal, i.e., the output terminals 29a to 29c on the terminal device 21 side are unknown, the internal terminal is incorporated into the input / output terminal 26. The control unit 40 automatically searches for the input / output terminal of the busy signal on the terminal device 21 side.
28 storage units.

Therefore, the operator connects the devices 21 and 23 with the cable 22 to which all pins # 1 to # 25 are connected, and
Only by inputting the search command of the busy signal input / output terminal at 39, the busy signal input / output terminal is automatically registered in the main unit 28, so that the data transmission / reception between the devices 21 and 23 can be started immediately. Can be. Therefore, the adjustment work when newly connecting the processing devices is greatly simplified,
The burden on the operator can be greatly reduced.

By using the method of the present invention, not only the busy signal input terminal can be detected, but also the directions of the driver and the receiver can be easily determined by the same method, so that the input / output terminal is very easy to handle. Can be.

[Effects of the Invention] As described above, in the input / output terminal of the present invention, a busy signal is forcibly transmitted from the external device and the main unit, and data transmission from the external device to each input / output terminal is stopped. By examining the response related to the signal level inversion, the input / output terminal of the busy signal is specified. Therefore, when the processing devices are connected to each other using the cable, the adjustment work related to the connection can be performed in a short time, and correct data transmission and reception can be started immediately. Therefore, even if the input / output terminal of the busy signal is unknown, the connection between the processing devices can be easily changed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a terminal device incorporating an input / output terminal and an external device according to an embodiment of the present invention.
FIGS. 3 and 3 are flowcharts showing the operation of the embodiment, FIG. 4 is a schematic diagram showing a general connection method, and FIG. 5 is a diagram showing a terminal arrangement of a general connection connector. 21 Terminal device, 22 Cable, 23 External device, 2
4, 25 connector, 26 input / output terminal, 28 main unit, 29a to 29c output terminal, 30a to 30c driver, 31a to 31e input terminal, 32a to 32e receiver
33 ... output interface, 34 ... input interface, 36 ... CPU, 40 ... control unit.

Claims (1)

(57) [Claims] A transmission data and various control signals output from a main unit (28) are transmitted to respective output terminals (29) of a connector (24).
a to 29c) and a data transmission / reception destination external device (23) via a cable (22), and from the external device, input terminals (31a to 31e) of the cable and the connector.
An input / output terminal (26) for transmitting received data and various control signals input through the main unit to the main unit, wherein the data is continuously input from the external device in response to a data continuous transmission request. Signal level inversion means (S3) for sequentially inverting each signal level of each output terminal;
Busy signal output terminal detecting means for judging an output terminal whose signal level has been inverted when data input from the external device has stopped in response to the signal level inversion of each output terminal to be a busy signal output terminal from the main unit side ( S4, S7), signal level detecting means (S11) for detecting a signal level of each of the input terminals during a period in which a processing request having a large processing capacity is continuously transmitted to the external device, and the signal level detecting means. An input / output terminal provided with busy signal input terminal detection means (S12, S15) for judging an input terminal for which signal level inversion has been detected as a busy signal input terminal from the external device side.