JP3394324B2 - False signal removal device and printer buffer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an erroneous signal removing device and a printer buffer, and more particularly to an erroneous signal removing device for removing an erroneous signal generated in a signal line between a computer and peripheral devices when the computer is turned on or off. The present invention relates to a device and a printer buffer including the false signal removing device.

[0002]

2. Description of the Related Art Conventionally, various parts of a computer are provided with various noise countermeasure techniques. For example, a shield that prevents the generation of noise due to the influence of external electromagnetic fields, a filter that attenuates noise from external power sources and noise in the transmission signal, insulation processing from noise sources using photocouplers, insulation transformers, etc. It has been known. These techniques are also applied to the connection between a computer and peripheral devices, and various types of noise are removed to ensure reliable data exchange.

[0003]

However, there is a problem in that when the power of the computer is turned on or off, the peripheral devices may behave abnormally even if the above noise removal technique is applied. The computer does not immediately enter an electrically established state when the power is turned on. During this time, the level of the input / output terminal of the computer becomes unstable, and an erroneous signal may be output to the signal line with the peripheral device. This signal may accidentally become a signal related to transmission / reception to / from the peripheral device. If the peripheral device is powered on at this time, the peripheral device receives the signal related to transmission / reception and operates according to the instruction. Indicates. Unlike the noise due to the influence of external electromagnetic fields and the noise entering from the power supply, this signal related to transmission and reception is output when the computer is in an unstable state where it is not electrically established. Cannot be removed. Similar problems occur when the computer is in an electrically unstable state immediately after it is turned off.

The erroneous signal removing device and the printer buffer of the present invention solve these problems and eliminate the erroneous signal generated in the signal line between the computer and the peripheral equipment at the time of turning on or off the power of the computer. The following configuration was adopted for the purpose of preventing malfunction of the peripheral equipment based on it.

[0005]

According to a first erroneous signal elimination device of the present invention, a power cable of a computer is connected,
Has an outlet that supplies commercial power to the computer
And controls the connection state of the switching on and off and the computer and peripherals power of the computer, erroneous removing false signal occurs in the signal line between the computer and the peripheral device at power up of the computer A signal removing device, which is a connector of an input / output interface of the computer.
Connector to the input / output interface of
Connected and send data between the computer and the peripheral
A connector part for receivable connection and the computer
And turning on or off and starting switch for starting the execution of the control of the connection state between the computer and peripherals power, the
If the start switch is turned off,
Turn off the power to the connector and
The kicking connection state between terminals in charge of signal permissibility of the transmission and reception of at least the data of the connection between the computer and the peripheral device, a state setting means for setting the non-receiving state in the normal operation of the computer, the starting Switch
The computer when the switch is changed from off to on.
Power on the, and summarized in that after the computer has shifted to the normal operation, and a state release unit operable to release the non-reception state and connection state of passing <br/> normal to said connector portion To do.

A second erroneous signal removing apparatus of the present invention, competent
Computer power cable is connected to the computer
The computer having an outlet for supplying commercial power
And controls the connection state of the switching on and off and the computer and peripherals power, in the false signal removing apparatus for removing false signal occurs in the signal line between the computer and the peripheral device power is interrupted when the computer Yes , the computer
Input / output interface connector and
Connected to the connector of the input / output interface,
The computer and the peripheral device so that data can be transmitted and received.
The connector part and the power on / off of the computer
Actual connection state control of the micro the computer and peripherals
Line start switch and the start switch
When it changed to the off from down, prior to the power <br/> shield interruption of said computer, at least transmission and reception of data among the connection state between the computer <br/> over data to the peripheral device in the connector portion permissibility State setting means for setting the connection state between the terminals that control the signal of 1 to a non-transmission / reception state during normal operation of the computer, and power cutoff means for cutting off the power of the computer after the non-transmission / reception state is set. The point is to have prepared.

The printer buffer of the present invention intervenes in the connection between the computer and the printer, and temporarily stores the control signal and the print data output by the computer toward the printer in accordance with the operation of the computer. A erroneous signal elimination device according to claim 1 or an erroneous signal elimination according to claim 2, which is a printer buffer comprising: an output means for outputting the stored control signal and print data in accordance with the operation of the printer. The gist is that at least one of the devices is provided so as to be interposed between the computer and the storage means.

[0008]

The first erroneous signal removing device of the present invention having the above-described structure is provided with the above-described outlet, connector section, and starting switch.
Equipped with a switch and the start switch is turned off,
When the state setting means turns off the computer
At the same time, among the connection states of the computer and the peripheral devices in the connector section, at least the connection state between the terminals that control the signal of permission / prohibition of data transmission / reception is set to the non-transmission / reception state during normal operation of the computer. Start switch off
When changed to ON from the state releasing means, power on the computer, the computer after the transition to normal operation, the connector portion and the normal connection state by releasing the non-reception state.

A second erroneous signal removing apparatus of the present invention is the above-mentioned
It is equipped with an outlet, a connector, and a start switch.
When switch is changed from ON to OFF, the state setting means, prior to shutdown the power supply of the computer, the connector portion
Among the connection states of the computer and the peripheral devices in the computer, at least the connection state between the terminals that control the signal of permission / prohibition of data transmission / reception is set to the non-transmission / reception state during normal operation of the computer. The power cutoff means cuts off the power of the computer after being set to the non-transmission / reception state.

In the printer buffer of the present invention, the error signal removing device according to claim 1 or the error signal removing device according to claim 2 may cause the computer to output to the printer when the power of the computer is turned on or off. Eliminates false signals. As a result, the printer buffer does not store an erroneous signal that the computer may output when the power is turned on or off, and does not output this erroneous signal to the printer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In order to further clarify the structure and operation of the present invention described above, an erroneous signal removing device 40 as a preferred embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram illustrating a schematic configuration of a computer system 10 in which an erroneous signal removing device 40 as a preferred embodiment of the present invention is used for connecting a computer 20 and a printer 30, and FIG. It is explanatory drawing which showed operation | movement of each circuit etc. at the time of ON and OFF. As shown in FIG. 1, the computer system 10 includes
Computer 20, printer 30, computer 2
0, and is provided with an erroneous signal removing device 40 that intervenes in the connection between the computer 20 and the printer 30.

The computer 20 is a CPU (not shown).
(For example, Intel 80486), ROM, RAM
And various interfaces, and is operated by receiving power supply from the power cable 22. A connection cable 26 is connected to a connector 23 of a printer interface (so-called Centronics interface) of the computer 20, and a connection connector 24 is attached to the tip of the connection cable 26. The connection connector 24 is connected to a connection connector 84a of the erroneous signal removing device 40 described later. Although not shown, various input / output devices such as a keyboard, CRT, HDD, FDD, and mouse are connected to various interfaces of the computer 20, and the computer 20 uses applications read from the input / output devices such as HDD and FDD. According to software processing, each processing including data exchange with each input / output device is performed.

The printer 30 has an input / output interface (not shown), and a connection cable 36 is connected to a connector 33 provided in this input / output interface. At the tip of the connection cable 36, the connection connector 3
4 is attached, and an erroneous signal removing device 40 described later is provided.
Is connected to the connector 84b.

The erroneous signal removing device 40 includes an erroneous signal removing device 4.
Power source unit 50 that supplies power to the computer 20 and power source to the computer 20.
Electronic circuit unit 70 that operates by receiving power supply via 0
And a connector section 80 for interposing the connection between the computer 20 and the printer 30. The electronic circuit unit 70 also turns on / off the power to the computer 20 and controls the connection state between the computer 20 and the printer 30.

The power supply unit 50 has a plug 52 for connecting to a commercial power supply, an outlet 54 for supplying power to the computer 20, and a power switch SW1 of the erroneous signal removing device 40.
And a relay R for supplying power to the computer 20
The contact point 56 of No. 1 is connected by a conductive line. A power unit 60 is connected to the power supply unit 50 on the downstream side of the power switch SW1. Power is supplied to the power unit 60 as long as the power switch SW1 is on even if the contact 56 of the relay R1 is not closed. The power supply to the computer 20 is such that the power switch SW1 is on and the contact 5 of the relay R1.
Delivered only when 6 is closed. The contact 56 of the relay R1 is normally open, and
Is closed when a low level signal is input from the electronic circuit section 70 and turned on, and is opened when the relay R1 receives a high level signal and is turned off.

The power unit 60 is supplied with electric power from the conductive line and is supplied with a predetermined voltage (for example, 5) from commercial alternating current.
V) is a unit for extracting a stable DC voltage. The high-potential-side terminal supplied from the power unit 60 is grounded via a resistor R and a mechanical start switch SW2. The contact point between the resistor R and the start switch SW2 is connected to the electronic circuit section 70. Therefore, the electronic circuit unit 70 has a start switch S.
When W2 is off, a signal pulled up to a predetermined voltage (high level signal) is input, and when the start switch SW2 is on, a grounded signal (low level signal) is input.

The electronic circuit section 70 includes a chattering removal circuit 72 for removing chattering when the starting switch SW2 is turned on and off, a delay circuit 74 for delaying and inverting the input signal for a predetermined time tw, and outputting the input signal. It is comprised of a NOT circuit 76 which inverts and outputs the signal, an AND circuit 78 which outputs a logical product of the input signals, and a NOR circuit 79 which outputs a logical sum of the input signals.
Here, the chattering removal circuit 72 is configured as a type of circuit that removes chattering by a one-shot multivibrator driven in synchronization with an input signal.

As shown in FIG. 1, the chattering removing circuit 72 removes the chattering when the starting switch SW2 is turned on and off.
4 and the NOT circuit 76. Delay circuit 74
The signal delayed by a predetermined time tw and inverted, and the signal inverted by the NOT circuit 76 are both input to the AND circuit 78 where they are ANDed and the AN of the connector section 80, which will be described later, is performed.
It is output to one input terminal of the D circuit 88. Further, the signal from the delay circuit 74 and the signal from the NOT circuit 76 are both input to the NOR circuit 79, logically summed and inverted, and output to the relay R1.

The connector section 80 includes a connection connector 24 on the computer 20 side and a connection connector 34 on the printer 30 side.
Is provided between the computer 20 and the printer 30, and controls the data exchanged between the computer 20 and the printer 30 when the start switch SW2 is turned on or off.
4 and the connection connector 3
4 and the computer 2
The signal receiver 86a that inputs the signal DATA.STB \ from 0, the AND circuit 88, and the signal driver 8 that outputs the signal DATA.STB \ to the printer 30 side.
6b. The signal receiver 86a and the signal driver 86b are Schmitt trigger type inverters that invert the input signal, adjust the waveform, and output. Here, as the data exchanged between the computer 20 and the printer 30, 8-bit data D0 to D7, a signal DATA.STB \ for notifying that the data D0 to D7 are valid, and the printer 30 currently operating and the data D0 To signal D7, a signal BUSY indicating that the data D0 to D7 have not been received, and a signal ACK \ indicating that the reading of the data D0 to D7 has ended normally. The symbol "\" added after the signal name indicates that the signal is low active (negative logic).

In the connector section 80 of the embodiment, the signal DAT
Each signal except A / STB \ is output as it is from the computer 20 to the printer 30 or from the printer 30 to the computer 20 via the connection connector 84a and the connection connector 84b. The signal DATA · STB \ output from the computer 20 is a signal receiver 86.
The signal is inverted and the waveform is adjusted by a, is input to the AND circuit 88, is ANDed with the signal from the AND circuit 78, is further inverted and the waveform is adjusted by the signal driver 86b, and is output to the printer 30 side. It Although not shown, the output of the signal driver 86b is an open collector, and the signal DATA.STB \
Is pulled up on the printer 30 side.

Next, the operation of the thus-configured computer system 10 when the start switch SW2 is on or off will be described. As shown in FIG. 2, when the start switch SW2 is turned on, the one-shot multivibrator in the chattering removal circuit 72 outputs an inverted pulse signal at the first fall of the signal, and when the start switch SW2 is turned on. Remove chattering. Therefore, the signal from the chattering removal circuit 72 falls cleanly to the low level. This signal is NO
The NOR circuit 7 is inverted by the T circuit 76 and becomes high level.
9 is input. The signal from the delay circuit 74 input to the NOR circuit 79 is still low level when the signal from the NOT circuit 76 is high level.
The signal from the NOR circuit 79 becomes low level when the signal from the NOT circuit 76 becomes high level. As a result, the relay R1 is turned on and the contact 5 of the relay R1
6 is closed and the computer 20 is powered on. Since the computer 20 requires some time (establishment time T2) until it is electrically established even when the power is turned on, during that time, the computer 20 connects the connection cable 26.
The output signal to is in an unstable state. The establishment time T
The number 2 is different for each computer 20, but is set within a predetermined time.

The signal which is inverted by the NOT circuit 76 and becomes high level is also input to the AND circuit 78.
The signal from the circuit 78 remains low level until the signal from the delay circuit 74 becomes high level. After a lapse of a predetermined time tw from when the starting switch SW2 is turned on, the signal from the delay circuit 74 becomes high level, and therefore the signal from the AND circuit 78 also becomes high level. Therefore, the signal from the AND circuit 78 becomes high level after a lapse of a predetermined time tw after the power of the computer 20 is turned on.

The AND circuit 88 outputs a logical product of the signal from the AND circuit 78 and the signal from the signal receiver 86a. Therefore, when the signal from the AND circuit 78 is at the low level, the AND circuit 88 is irrelevant to the signal from the signal receiver 86a. Instead, it outputs a low level signal, and when the signal from the AND circuit 78 is at a high level, it outputs the signal from the signal receiver 86a as it is. Therefore, the AND circuit 88 outputs the low level signal for the predetermined time tw after the start switch SW2 is turned on, and thereafter outputs the signal from the signal receiver 86a as it is. The signal DATA.STB \ from the computer 20 is inverted by the signal receiver 86a, and the signal from the AND circuit 88 is inverted by the signal driver 86b.
The signal output to 0 is maintained at the high level for a predetermined time tw after the start switch SW2 is turned on, and thereafter has the same signal level as the signal DATA.STB \ from the computer 20. As a result, after the lapse of the predetermined time tw, the computer 20 is connected to the printer 3 in the same manner as in the case where the computer 20 is directly connected to the printer 30 without the error signal removing device 40.
It is possible to send and receive data to and from 0. For example, in FIG.
When the computer 20 outputs an inverted pulse signal from the port DATA.STB \ (the data D0 to D7 are valid) like the point P1 in the middle, the signal from the AND circuit 88 further inverts the inverted pulse signal. And the signal output to the printer 30 is the same inverted pulse signal as the signal output from the port DATA.STB \.

In the embodiment, the predetermined time tw is set to be equal to or longer than a time (establishing time T2) from when the starting switch SW2 is turned on to when the computer 20 is electrically established and a stable signal can be output. Therefore, an erroneous signal that may be output to the connection cable 26 when the computer 20 is in an electrically unstable state is not output to the printer 30.

Next, the operation when the starting switch SW2 is turned off will be described. When the starting switch SW2 is turned off, the one-shot multivibrator in the chattering removal circuit 72 outputs an inverted pulse signal at the first rising thereof to remove chattering when the starting switch SW2 is off. The high level signal that rises cleanly is inverted by the NOT circuit 76 and input to the AND circuit 78, so that the signal from the AND circuit 78 becomes low level regardless of the signal from the delay circuit 74. Since this low-level signal is input to the AND circuit 88 together with the signal DATA.STB \ from the computer 20, the signal from the AND circuit 88 becomes low level regardless of the signal DATA.STB \ from the computer 20. . Therefore, the signal output to the printer 30 is maintained at the high level (the state in which the data D0 to D7 are not valid). As a result, the computer 20 sends a low level signal (data D
0 to D7 are valid), the printer 3
0 does not work.

The signal from the delay circuit 74, which becomes low level after a predetermined time tw from the time when the starting switch SW2 is turned off, is input to the NOR circuit 79 together with the signal from the NOT circuit 76, and the logical sum is obtained. Therefore, the signal from the NOR circuit 79 is inverted by the NOT circuit 76.
Is kept low until a predetermined time tw elapses, and becomes high when the signal from the delay circuit 74 goes low after a predetermined time tw elapses. Therefore, the NOR circuit 79
The relay R1 which is operated by the signal from is kept on (the contact 56 is closed) for a predetermined time tw even when the start switch SW2 is turned off, and is turned off (the contact 56 is opened when the predetermined time tw elapses. Then, the power to the computer 20 is cut off.

When the power supply to the computer 20 is cut off, the computer 20 stops after an unstable state in which an unstable signal may be output to the connection cable 26. However, since the signal output to the printer 30 is maintained at the high level (the signal from the AND circuit 88 is the low level) regardless of the signal from the computer 20, the computer 20 in an electrically unstable state is connected. Even if an erroneous signal is output to the cable 26, the printer 30 does not operate.

According to the erroneous signal removing apparatus 40 described above, when the power of the computer 20 is turned on or off, the signal DATA is output regardless of the output signal from the computer 20.
Since STB \ is set to a high level to output to the printer 30 that the data D0 to D7 are not valid, the computer 20 outputs the data when the computer 20 has not electrically established its input / output state. An erroneous signal that may occur can be reliably eliminated. As a result, the printer 30 does not operate undesirably due to an erroneous signal output from the computer 20.

The erroneous signal removing apparatus 40 of the embodiment is
Although the chattering is removed by providing the one-shot multivibrator in the chattering removal circuit 72, the configuration in which the chattering is removed using the integrating circuit, R
A configuration in which chattering is removed by using an S latch, a configuration in which chattering is removed by using a shift register, and the like are also preferable.

Further, in the present embodiment, the computer 20 and the printer 30 are directly connected to the single error signal elimination device 40, but a structure in which a printer buffer is interposed in the connection between the error signal elimination device 40 and the printer 30 or a printer is used. A configuration in which the false signal removing device 40 is incorporated in the buffer is also suitable. A configuration in which the error signal removing device 40 is incorporated in the printer buffer 90 will be described.

In FIG. 3, the computer 20 and the printer 3 are arranged in a printer buffer 90 in which the error signal removing device 40 is incorporated.
It is explanatory drawing which shows a mode that 0 and were connected. As shown in the figure, the printer buffer 90 has an erroneous signal removing device 4 inside.
0, a buffer unit 92 having the original function of the printer buffer, and a connection connector 94b for connecting to the connection cable 36 of the printer 30. The false signal removing device 40 is
It is arranged between the computer 20 and the buffer unit 92.

The buffer unit 92 reads the print data and the control signal input from the computer 20 via the erroneous signal removing device 40 and sequentially stores them in the RAM 93 provided therein. The buffer unit 92 outputs the signal BUSY to the computer 20 while the data is being stored in the RAM 93, and when the storage is completed, the buffer unit 92 outputs the signal ACK \ to the computer 20.
Is output. Further, the buffer unit 92 determines the RA based on the signal BUSY and the signal ACK \ output from the printer 30.
The print data sequentially stored in M93 is sequentially output to the printer 30.

In the printer buffer 90 configured as described above, since the buffer section 92 inputs the data from the computer 20 via the erroneous signal removing device 40, the computer 20 is turned on and off when the power is turned on. The RAM 93 does not store an erroneous signal that may be output by the. Therefore, this erroneous signal is not output to the printer 30 and the printer 30 is not operated undesirably.

Next, a description will be given of a case where the error signal elimination device 140 as the second embodiment of the present invention is interposed in the connection (RS-232C interface) between the computer 20 and the modem. The erroneous signal elimination device 140 of the embodiment has the same configuration as the erroneous signal elimination device 40 of the first embodiment except for the connector section 180, and therefore the same components are designated by the same reference numerals and their description is omitted. Is omitted. FIG. 4 is a partial block diagram showing the connector section 180 of the false signal removing apparatus 140,
FIG. 5 is an explanatory diagram showing how the AND circuits 188a, 188b and the like operate when the start switch SW2 of the erroneous signal removing device 140 is turned on and off.

RS-23 (not shown) of the computer 20
The connection cable 126 is connected to the connector provided in the 2C interface, and the connection connector 124 is attached to the tip of the connection cable 126. On the other hand, the connection cable 136 is also connected to the connector provided in the interface of the modem, and the connection connector 134 is attached to the tip of the connection cable 136.

The connector section 180 includes a connection connector 124 on the computer 20 side and a connection cable 136 on the modem side.
For controlling the data exchanged between the computer 20 and the modem when the start switch SW2 is turned on or off, and the connection connector 184a connected to the connection connector 124 and the connection connector 34.
Connector 184b connected to the computer 2 and the computer 2
Two signal receivers 186a and 187a for inputting a signal DTR \ and a signal RTS \ from 0 and two ANDs
Circuits 188a and 188b and a signal DTR \, to the modem side
Two signal drivers 186 that output the signal RTS \
b, 187b. Two signal receivers 18
6a, 187a and two signal drivers 186b, 1
87b is a Schmitt trigger type inverter that inverts the input signal, adjusts the waveform, and outputs. Here, as the data exchanged between the computer 20 and the modem, the transmission data TxD, the reception data RxD, the signal DSR \ for notifying the computer 20 of whether or not the data can be transmitted by the modem, and whether or not the state of the computer 20 can be received. Signal DTR \ to inform modem, computer 20
There is a signal RTS \ for notifying the modem whether or not there is transmission data from the computer, a signal CTS \ for the modem requesting the computer 20 to cancel the transmission data, and the like.

In the connector section 180 of the second embodiment, each signal except the signal DTR \ and the signal RTS \ is directly output from the computer 20 to the modem or from the modem to the computer 20 via the connection connector 184a and the connection connector 184b. To be done. The signal DTR \ and the signal RTS \ output from the computer 20 are inverted and waveform-adjusted by signal receivers 186a and 187a, respectively, and input to AND circuits 188a and 188b,
The logical product of the signals from the AND circuit 78 is obtained, the signals are inverted and the waveforms are adjusted by the signal drivers 186b and 187b, and output to the modem. Although not shown, the outputs of the signal drivers 186b and 187b are open collectors.

Therefore, the signal DTR \ and the signal RTS \ output from the error signal eliminating device 140 to the modem are
When the signal from the AND circuit 78 is low level, regardless of the signal from the computer 20, a high level (AND
Circuits 188a and 188b go low) and A
When the signal from the ND circuit 78 is at the high level, the signal level from the computer 20 is obtained (the AND circuits 188a and 188b are inverted levels) (see FIG. 5).

Since this erroneous signal removing device 140 also has the same configuration as the above-mentioned erroneous signal removing device 40, when the start switch SW2 of the erroneous signal removing device 140 is turned on or off, the same operation as that shown in FIG. 2 is performed. Indicates. When the start switch SW2 is turned on, the signal DTR \ and the signal RTS \ output to the modem are irrespective of the signal from the computer 20 for a predetermined time tw until the signal from the delay circuit 74 becomes high level. As a high level (AND circuits 188a and 188b are low level), it informs the modem that the computer 20 is in the unreceivable state and that the computer 20 has no data to be transmitted.
Therefore, even if the computer 20 which is turned on immediately after the start switch SW2 is turned on and outputs an erroneous signal, the computer 20 does not communicate with the modem.

When a predetermined time tw has passed since the start switch SW2 was turned on, the signal from the AND circuit 78 becomes high level, so the signal DT output to the modem is given.
R \ and signal RTS \ have the same signal level (AN as signal DTR \ and signal RTS \ from computer 20).
The D circuits 188a and 188b have inverted levels). For this reason, the computer 20 can communicate after a predetermined time tw as in the case where the computer 20 is directly connected to the modem without passing through the error signal elimination device 140.

On the other hand, when the start switch SW2 is turned off, the signal from the AND circuit 78 immediately becomes low level, so that the signal DTR \ and the signal R output to the modem are output.
TS \ is at a high level (AND circuits 188a and 188b are at a low level) regardless of the signal from the computer 20. Therefore, the computer 20 then
Unable to communicate with the modem. Start switch SW2
Is turned off and when a predetermined time tw has elapsed, the signal from the delay circuit 74 becomes low level, so NOR
The signal from the circuit 79 becomes high level, the relay R1 is turned off (contact 56 is opened), and the power supply to the computer 20 is cut off. At this time, the computer 20 may be in an electrically unstable state by the time it is completely stopped and output an erroneous signal to the connection cable 126. However, as described above, the computer 20 cannot communicate with the modem. Does not cause undesired operation.

According to the erroneous signal removing device 140 described above, when the power of the computer 20 is turned on or off, the signal DTR \ is output regardless of the output signal from the computer 20.
And the signal RTS \ is set to high level, and the computer 2
An error signal that may be output by the computer 20 when the computer 20 has not electrically established its input / output state, since 0 is output to the modem side indicating that it is not receivable and there is no transmission data. Can be reliably excluded. As a result, the modem does not operate undesirably due to an erroneous signal output from the computer 20.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. Of course. For example, RS
-A configuration in which an erroneous signal elimination device is interposed in another connection using the 232C interface (for example, a computer-to-computer connection), a configuration in which an error signal elimination device is interposed in a connection using the GPIB interface, and an erroneous signal elimination is performed in a connection using the SCSI interface. A configuration in which the device is interposed is also suitable. The erroneous signal removing device in these configurations outputs a control signal indicating that the computer is in a non-transmission and reception disabled state (non-transmission / reception state) regardless of the control signal output from the computer when the computer is not powered on. When the output is output to the peripheral device and it is instructed to turn on the computer, the non-transmission / reception state is released after the computer is electrically turned on and the computer is electrically established, and the computer and the peripheral device are normally connected. When the power of the computer is turned off, a control signal indicating that the computer is not transmitting and cannot receive regardless of the control signal output by the computer is sent to the peripheral device before the power of the computer is turned off. It outputs and then shuts off the computer power.

[0044]

As described above, according to the first erroneous signal elimination device of the present invention, the starting switch is turned off.
In this case, turn off the computer and
The connection state between the computer and peripheral devices in the connector was set to the non-transmission / reception state during normal operation of the computer, and the start switch was changed from off to on.
When the computer is not electrically established , the power is turned on and the non-transmission / reception state that was set after the computer has moved to normal operation is released and the connector section is set to the normal connection state. An erroneous signal that may be output to the device can be reliably eliminated. As a result, the peripheral device does not perform an undesired operation due to an erroneous signal output from the computer.

According to the second erroneous signal removing apparatus of the present invention,
When the start switch is changed from on to off, the connection
The computer power is turned off after the connection state between the computer and peripheral devices in the computer is set to the non-transmission / reception state during normal operation of the computer. Therefore, the computer is electrically unstable immediately after the power is turned off. It is possible to reliably eliminate an erroneous signal that may be output by the computer at. As a result, the peripheral device does not perform an undesired operation due to an erroneous signal output from the computer.

According to the printer buffer of the present invention, the erroneous signal removing device according to claim 1 or the erroneous signal removing device according to claim 2 outputs the data to the printer when the computer is turned on or off. Since an erroneous signal that may occur is eliminated, it is possible to prevent erroneous signals that may be output by the computer from being stored when the computer is turned on or off. Therefore, without outputting this erroneous signal to the printer,
Undesired operation of the printer due to an erroneous signal can be eliminated.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an erroneous signal removing device 40 as an embodiment of the present invention.
2 is a block diagram illustrating a schematic configuration of a computer system 10 using the.

FIG. 2 is an explanatory diagram showing the operation of each circuit and the like when a starting switch SW2 is on and off.

FIG. 3 is an explanatory diagram showing a state in which a computer 20 and a printer 30 are connected to a printer buffer 90 incorporating an erroneous signal removing device 40.

4 is a partial block diagram showing a connector section 180 of the false signal removing apparatus 140. FIG.

FIG. 5 is an explanatory diagram showing a state of operation of each circuit when the start switch SW2 of the erroneous signal removing device 140 is on and off.

[Explanation of symbols]

10 ... Computer system 20 ... Computer 22 ... Power cable 23 ... Connector 24 ... Connector 26 ... Connection cable 30 ... Printer 33 ... Connector 34 ... Connector 36 ... Connection cable 40 ... False signal remover 50 ... power supply 52 ... Plug 54 ... Outlet 56 ... Contact 60 ... Power unit 70 ... Electronic circuit section 72 ... Chattering removal circuit 74 ... Delay circuit 76 ... NOT circuit 78 ... AND circuit 79 ... NOR circuit 80 ... Connector part 84a ... Connector 84b ... Connector 86a ... Signal receiver 86b ... Signal driver 88 ... AND circuit 90 ... Printer buffer 92 ... buffer section 93 ... RAM 94b ... Connector 124 ... Connector 126 ... Connection cable 134 ... Connector 136 ... Connection cable 140 ... False signal remover 180 ... Connector part 184a ... Connection connector 184b ... Connection connector 186a, 187a ... Signal receiver 186b, 187b ... Signal driver 188a, 188b ... AND circuit

Claims (3)

(57) [Claims] 1. A computer power cable is connected
An outlet that supplies commercial power to the computer.
A, and controls the connection state of the switching on and off and the computer and peripherals power of the computer to remove the false signal occurs in the signal line between the computer and the peripheral device at power up of the computer An erroneous signal removing device, comprising: an input / output interface connector of the computer;
Connect to the I / O interface connector of the peripheral device
Data transmission between the computer and the peripheral device
A connector section which connected, to start the execution of the control of the connection state of the switching on and off and the computer and peripherals power of the computer
The start switch and the companion if the start switch is off.
Turn off the power to the computer and
The connection state between the terminals responsible for definitive least data signals permission of transmission and reception of the connection between the computer and the peripheral device, a state setting means for setting the non-receiving state in the normal operation of the computer, the starting When the switch is changed from off to on,
Apply power to the serial computer, after the computer has shifted to the normal operation, the to cancel the non-reception state
An erroneous signal removing device comprising: a state releasing means for bringing a connector portion into a normal connection state. 2. A computer power cable is connected
An outlet that supplies commercial power to the computer.
A, and controls the connection state of the switching on and off and the computer and peripherals power of the computer to remove the false signal occurs in the signal line between the computer and the peripheral device to the power-off of the computer An erroneous signal removing device, comprising: an input / output interface connector of the computer;
Connect to the I / O interface connector of the peripheral device
Data transmission between the computer and the peripheral device
A connector section which connected, to start the execution of the control of the connection state of the switching on and off and the computer and peripherals power of the computer
When a start switch, the start switch is changed from on to off, prior to shutdown the power supply of the computer, the connector portion
A state setting means for the connection state between terminals in charge of permission signal transmitting and receiving at least the data of the connection between the computer and the peripheral device is set to a non-reception state in the normal operation of the computer in, non-reception An erroneous signal removing device comprising: a power-off means for turning off the power of the computer after being set to the state. 3. A storage means interposed between a computer and a printer, for temporarily storing a control signal and print data output by the computer toward the printer in accordance with the operation of the computer, and the stored means. It is a printer buffer provided with an output means which outputs a control signal and print data according to the operation of the printer, and at least one of the false signal removing device according to claim 1 or the false signal removing device according to claim 2. And a printer buffer provided between the computer and the storage means.