JPH01128116A - Keyboard adaptor - Google Patents

Abstract

PURPOSE:To omit the mechanical parts like a key lock mechanism, etc., by transmitting a key code string received from a keyboard with reception of a gate control signal and then stopping the gate control signal. CONSTITUTION:A detecting circuit 4 sets a detecting signal (a) at an H level with push of a control key 5 of a keyboard 1. Thus the output signal of an AND circuit 6 is set at an H level. Receiving the signal (a), a gate control FF 11 sets a signal b-1 at an L level. Then a gate circuit 12 stops the transmission of a key code received from the keyboard 1. A memory circuit 8 stores an identification character string supplied with push of keys. Thus the key locking action is through. Then the output signal of an AND circuit 7 is set at an L level with push of the key 5 and the circuit 8 outputs the stored key code string. When the identification character string supplied with push of keys are coincident with the output of the circuit 8, a comparator 10 sets a coincidence signal at an H level. Receiving this coincidence signal, the circuit 12 transmits the key code received from the keyboard 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a keyboard adapter that provides a key lock mechanism in a keyboard used in information processing equipment such as a computer.

[Conventional technology]

Generally, information processing equipment such as computers uses a keyboard as a data input device. If the operator leaves his/her seat while the computer is in a usable state, or if a third party enters the wrong keys on the keyboard during the night, the system may malfunction, or a person with malicious intent may misuse the computer. There is a risk that it may be used.

In order to prevent such a situation, conventionally, the keyboard has been provided with a physical key lock.

[Problem that the invention seeks to solve]

As described above, conventional keyboards have a physical lock for key locking, which requires a mechanical part such as a key lock mechanism, which has the disadvantage of increasing manufacturing costs. Another disadvantage was that the keyboard became larger due to the need for space to install the key lock mechanism.

In view of these problems, it is an object of the present invention to provide a key locking device that does not require a physical lock.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a keyboard adapter provided with the following means.

A: Detection means that detects a control key code from among the key codes sent from the keyboard and outputs a detection signal.

B. A first logic operation means that outputs the AND of the detection signal and the gate control signal.

a second logical operation means for outputting an AND of the C detection signal and an inverted signal of the gate control signal;

D By receiving the output of the first logic operation means, it starts capturing the key code string sent from the keyboard and stores the same key code string, and by receiving the output of the second logic operation means, A storage means that outputs a memorized key code string.

E By receiving the output of the second logic operation means, the key code string sent from the keyboard and the key code string sent from the storage means are compared, and when all of these key code strings match, a match is determined. A comparison means that outputs a signal.

F. A gate control means that starts outputting a gate control signal upon receiving a coincidence signal, and stops outputting a gate control signal upon receiving a detection signal.

G. Gate means that transmits a key code string sent out from the keyboard by receiving a gate control signal, and cuts off the key code string sent out from the keyboard by stopping the gate control signal.

[Effect]

Control keys are set on the keyboard for controlling the keyboard adapter of the present invention. First, the operator presses this control key. This causes the control key code to be sent from the keyboard. The detection means detects the key code and outputs a detection signal.

Normally, the gate control means outputs a gate control signal. Therefore, upon receiving the detection signal, the first logic operation means outputs an output, and the second logic operation means does not output at this point. Further, upon receiving the detection signal, the gate control means stops outputting the gate control signal. As a result, the gate means stops and interrupts the transmission of the key code sent from the keyboard.

Next, the operator presses the required number of keys (password string). The storage means starts operating upon receiving the output of the first logic operation means, takes in the key code string of the password string, and stores it in memory. The key lock is now complete.

To release the key lock, the operator first presses the above control key. The detection means detects the control key code and outputs a detection signal. Since the gate control signal is not output at this time, the second logic operation means outputs the result of the logic operation. The storage means operates upon receiving the output of the second logic operation means, and outputs the above-mentioned stored key code string to the comparison means.

Next, the operator types the password string. The comparing means operates in response to the output of the second logical operation means, and compares the key code string sent from the keyboard with the key code string sent from the storage means. If the entered password string is correct, that is, if both key code strings match, a match signal is output. Upon receiving this coincidence signal, the gate control means starts outputting a gate control signal, and upon receiving this, the gate means resumes transmission of the key code sent from the keyboard. This releases the key lock.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the structure of a keyboard adapter according to an embodiment of the present invention.

First, each component in FIG. 1 will be briefly explained.

When a key is pressed, the keyboard 1 sends a key code assigned to the key to the keyboard adapter 2. The keyboard adapter 2 transmits the above-mentioned key code to the computer 3 in the normal state, and shuts it off in the key lock state.

Note that although the keyboard 1 and the keyboard adapter 2 are shown separately in the figure for convenience of explanation, the keyboard adapter 2 is normally built into (added to) the keyboard 1.

Next, each part of the keyboard adapter 2 will be explained. A key code sent from the keyboard 1 is input to a detection circuit 4, a memory circuit 8, a comparator 10, and a gate circuit 12. The detection circuit 4 detects the control key code from among them, and outputs a detection signal when the key code is detected. The control key code is a key code given to the control key 5 set on the keyboard 1. The first AND circuit 6 is
It outputs the AND of the detection signal and a gate control signal, which will be described later. The second AND circuit 7 outputs the logical product of the detection signal and an inverted signal of a gate control signal, which will be described later. Upon receiving the output signal of the first AND circuit 6, the memory circuit 8 starts capturing the key code string, stores the same key code string, and receives the output signal of the second AND circuit 7. This outputs the stored key code string. The backup circuit 9 is
This is to back up the memory circuit 8 in order to save the memory contents of the memory circuit 8 when the power (not shown) is turned off. The comparator 10 receives the key code string sent out from the keyboard 1 and the key code string sent out from the memory circuit 8, and receives the output signal from the second AND circuit 7 to input both key code strings. Compare the
When the two match, a match signal is output. The gate control flip-flop 11 starts outputting a gate control signal when receiving a coincidence signal, and stops outputting a gate control signal when receiving a detection signal. The gate circuit 12 transmits the key code sent from the keyboard 1 to the computer 3 by receiving a gate control signal, and interrupts transmission of the key code by stopping the gate control signal.

Next, the operation of this keyboard adapter will be explained with reference to FIG. FIG. 2 shows the waveforms of each part of this keyboard. First, the key lock operation will be explained. To operate, press the control key 5 on the keyboard 1. As a result, the control key code is sent out from the keyboard 1. The detection circuit 4 detects the same key code, and the detection signal (a in the figure) becomes "l" and becomes a bell.

Normally, the gate control signal (low 1 in the figure) is at H level, and the gate circuit 12 transmits the key code sent from the keyboard 1. Note that row 2 in the figure shows an inverted signal of the gate control signal. Therefore, at this time, the output signal of the first AND circuit 6 (FIG. 3C) becomes H level. Upon receiving this detection signal, the gate control flip-flop 1
1 sets the gate control signal to L level. As a result, the gate circuit 12 stops and cuts off the transmission of the key code.

The operator then enters a PIN string, for example rHIRAKE.
Press GOMAJ. The memory circuit 8 starts operating in response to the fact that the output of the first AND circuit 6 is at H level, takes in and stores the key code string "rHrRAKEGOMΔ".

The key lock is now complete. Thereafter, even if the power is turned off, the backup circuit 9 backs up the memory circuit 8 and the stored contents are preserved.

To release the key lock, the operator first presses the control key 5 mentioned above.

Then, the detection circuit 4 detects the control key code and sets the detection signal to H level. At this time, since the gate control signal is at L level, the output signal of the second AND circuit 7 (FIG. 2) becomes H level. And the memory circuit 8 is
When the output signal is at H level, the stored key code string is output to the comparator 10.

Next, the operator types the password string. At this time, the comparator 10 detects that the output signal of the second AND circuit 7 is H.
In response to the level, the key code string sent from the keyboard 1 and the key code string sent from the memory circuit 8 are compared.

If the entered password string is correct, that is, if both key code strings match, the match signal (E in the figure) is set to H level. Furthermore, in response to this, the gate control flip-flop 11 sets the gate control signal to H level. In response to this, the gate circuit 12 resumes transmission of the key code sent from the keyboard 1. This releases the key lock.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide a keyboard adapter for key locking that is composed only of electrical elements, and unlike the past, mechanical parts such as a key locking mechanism are not required. It has the advantage of being inexpensive. Moreover, when this keyboard adapter is built into (added to) the keyboard, there is an advantage that the keyboard does not become larger.

Furthermore, this keyboard adapter allows you to instruct key lock and key unlock using a common control key.
When built into (added to) a keyboard, it has the advantage that it is only necessary to prepare one control key on the keyboard.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a keyboard adapter according to an embodiment of the present invention, and FIG. 2 is a waveform diagram showing waveforms of various parts in FIG. 1. DESCRIPTION OF SYMBOLS 1... Keyboard, 2... Keyboard adapter, 3... Computer, 4... Detection circuit, 5... Control key, 6. ...First AND circuit, 7... Second AND circuit, 8... Memory circuit, 9... Backup circuit, 10...・Comparator, 11...Gate control flip-flop, 12...Gate circuit. Applicant: NEC Corporation

Claims (1)

[Scope of Claims] Detection means for detecting a control key code from among the key codes sent from the keyboard and outputting a detection signal; and a first logic for outputting the AND of the detection signal and the gate control signal. a key code sent from the keyboard by receiving the output of the arithmetic means, the second logical arithmetic means that outputs an AND of the detection signal and the inverted signal of the gate control signal, and the first logical arithmetic means; a storage means for outputting the stored key code string by starting to import the key code string and storing the same key code string, and receiving an output from the second logical operation means; By receiving the output,
Comparing means for comparing a key code string sent from the keyboard with a key code string sent from the storage means and outputting a match signal when these key code strings match; , a gate control means that starts outputting a gate control signal and stops outputting the gate control signal upon receiving the detection signal; and upon receiving the gate control signal, transmits a key code sent from the keyboard. 1. A keyboard comprising: gate means for blocking a key code sent from the keyboard by stopping a gate control signal.