JPH07129297A - Keyboard extension device - Google Patents

Abstract

PURPOSE:To prevent a malfunction from an occurrence and an operation mode from becoming discrepant without generating a discrepancy in ON/OFF periods between a power source on the side of a computer and a power source on the side of a keyboard in a keyboard extension device which is used in the case where a computer body or computer terminal and the keyboard are installed at an extended distance. CONSTITUTION:A keyboard side extension device (2) 14 detects breaking/making of the power source of a computer body 11 based on variation of data (SD-1) sent to it and breaking/connection of a keyboard power supply line (+5V-2) from the power source that the extension device (2) 14 is equipped with to the keyboard 12 are controlled; start/stop of the power source of the computer body 11 is accompanied by start/stop of the power source of the keyboard 12 at nearly the same period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyboard extension device used for installing a computer main body or a computer terminal and a keyboard in such a manner that the keyboard and the keyboard are separated and extended.

[0002]

2. Description of the Related Art Generally, in an installation environment of a computer system, a keyboard operated by an operator and a computer main body are installed relatively distant from each other so that, for example, an operator room and a computer room are separated from each other. Often.

Normally, when the keyboard is installed close to the computer main body, the computer main body also directly supplies power to the keyboard, and various command data from the computer main body and key input data from the keyboard are directly transmitted and received. It

However, when the computer main body and the keyboard are installed at a distance of, for example, 2 m or more, problems such as a drop in the power supply voltage and mixing of noise in the transmitted / received signal occur between them, so that a relay device as a keyboard extension device is produced. The above problem is solved by intervening.

That is, the computer side extension device is installed within 2 m from the computer main body, the keyboard side extension device is installed within 2 m from the keyboard, and the extension devices are extendedly connected by a signal transfer cable of RS232C standard, for example. In this case, the power supply voltage for the keyboard is supplied from the power supply provided in the keyboard side extension device independently of the power supply in the computer main body.

Then, the RS232C signal transmitted from the computer main body or the keyboard is converted into a current loop signal in each corresponding extension device, and again converted into an RS232C signal in the counterpart extension device and received.

[0007]

On the other hand, as described above,
Using the keyboard extension device has the advantage that the power supply to the keyboard can be easily performed and the reliability of the transmitted and received signals can be secured even if the computer main body and the keyboard are installed separately. Since the power supply of the computer main body and the power supply of the keyboard are independent and separate, new problems as described below occur.

First, when only the power source of either the computer main body or the keyboard is turned off, the transient noise accompanying the fall of the power source becomes command data from the computer main body or key input data from the keyboard. There is a problem in that the keyboard or the computer main body, which is transmitted by mistake and remains powered on, may malfunction.

Secondly, when the power is turned on after turning off the power of only one of the computer main body and the keyboard in the power-on state of both, only the computer main body or the keyboard which is turned on is initialized. However, there is a problem that the operation mode does not match with the keyboard or the computer main body.

The present invention has been made in view of the above problems,
An object of the present invention is to provide a keyboard extension device capable of preventing occurrence of malfunction and inconsistency in operation mode without causing inconsistency in on / off periods between the main body power supply and the keyboard power supply. To do.

[0011]

That is, in a keyboard extension device according to the present invention, a keyboard and a main body device operated by the keyboard are connected via the extension device, and the keyboard power source is independent of the main body device power source. In the extension device, in the extension device, a main body power source detection means for detecting power off / on of the main body device, and a power source cutoff / power off of the main body device detected by the main body power source detection means are provided. A keyboard power supply control means for controlling shutoff / power-on of the keyboard power supply provided in the extension device in response to the power-on is provided.

[0012]

In other words, the keyboard power supply is also turned off / on in response to the power off / on of the main body device by the main body power supply detection means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a computer system using a keyboard extension device. For example, a computer main body 11 installed in a computer room and a keyboard 12 installed in an operator room are connected via a main body side extension device (1) 13 and a keyboard side extension device (2) 14.

The computer main body 11 and the extension device (1) 13
The distance between the keyboard 12 and the extension device (2) 1
All of the distances to 4 and 4 are set to a distance (for example, within 2 m) in which the drop of the power supply voltage and the mixing of noise do not occur.

The extension device (1) 13 and the extension device (2) 14 are extendedly connected between the computer room and the operator room, and transmission / reception between the computer main body 11 and the keyboard 12 is performed. The data conforms to the RS232C standard, and transmission data (SD-1), (SD-2) from the computer main body 11 to the keyboard 12 and the keyboard 12 are transmitted.
From the received data (RD-1) to the computer main body 11,
(RD-2) is + 8V at logic "0" and logic "1"
Is set to -8V and logic "1" when there is no data
It is held as it is (mark hold).

Here, when the power of the computer main body 11 is turned off, the transmission data (SD-1) is held constant at 0V, but in this case, it is treated as a logical "0". Between the computer main body 11 and the extension device (1) 13, (+ 5V-1) is a power supply line (unused), and (LG-1) is a ground line.

Further, the keyboard 12 and the extension device (2) 1
(+ 5V-2) between 4 and keyboard power supply line,
(LG-2) is a ground line. The transmission data (SD-1) from the computer main body 11 is converted into a transmission current loop signal (SD-c) and transferred between the extension devices (1) 13 and (2) 14 and the keyboard 1
The received data (RD-2) from 2 is converted into a received current loop signal (RD-c) and transferred, and each of the above current loop signals (SD-c) and (RD-c) is The current drive is turned off by the logic "0", and the current drive is turned on by the logic "1".

FIG. 2 shows a keyboard side extension device (2) 14 in a computer system using the keyboard extension device.
3 is a block diagram showing the internal configuration of FIG. The keyboard side extension device (2) 14 has a current / TTL conversion circuit 1
5, TTL / RS232C conversion circuit 16, RS232C
A current conversion circuit 17 is provided.

The current / TTL conversion circuit 15 converts the transmission current loop signal (SD-c) from the main body side extension device (1) 13 into a TTL level signal. This TTL signal (TTL) is A logic "0" sets 0V, and a logic "1" sets + 5V.

The above-mentioned TTL / RS232C conversion circuit 16
Is for converting the TTL signal from the current / TTL conversion circuit 15 into RS232C level transmission data (SD-2). The transmission data (SD-2) from the extension device (2) 14 is a keyboard 12 is transferred.

The RS232C / current conversion circuit 17
Is for converting RS232C level reception data (RD-2) from the keyboard 12 into a reception current loop signal (RD-c), and a reception current loop signal (RD-c) from the extension device (2) 14. Is transferred to the main body side extension device 13.

On the other hand, the current / TTL conversion circuit 15
The transmission data (SD-1) and the transmission current loop signal (SD-c) from TTL signal (TTL) are also supplied to the break detection circuit 18.

The break detection circuit 18 is based on the TTL.
When the duration "t" of the logic "0" at which the signal (TLL) becomes 0V has passed the predetermined time Dt measured by the timer T, the main body power is cut off to perform break detection. The break detection signal BR is supplied to the relay circuit (R) 19 and the relay switch S is turned off (cut off).

The relay switch S is a keyboard power supply line (+5) from the power source 20 to the keyboard 12.
V-2) is connected and disconnected, and the power supply voltage from the power supply 20 is also used as an internal power supply for the extension device (2) 14.

Here, the predetermined time Dt measured by the timer T of the break detection circuit 18 is the computer main body 1
Transmission data from 1 to keyboard 12 (SD-1)
It is set as the transfer time for one word of (SD-2).

That is, for example, when 1 word consists of 8-bit data and 1 ms is required for 1-bit transfer,
The predetermined time Dt is set as 8 ms, and in this case, the duration t of the logic "0" of the TTL signal (TTL) is
When 8 ms (= Dt) has passed, that is, when there is no data for one word, the break detection signal BR is output.

Next, the operation of the computer system using the keyboard extension device having the above configuration will be described. Figure 3
3 is a timing chart showing a power supply control operation of a computer system using the keyboard extension device.

That is, the keyboard power supply line (+ 5V) for the power supply of the computer main body 11 and the keyboard 12
-2) In the operating state of the computer system in which both are on, the transmission data (SD-1) (SD-2) and the reception data (RD-1) between the computer main body 11 and the keyboard 12
(RD-2) is an RS23 of 1-bit 8-bit configuration
It is transmitted and received as 2C level data, and is transmitted between the main body side extension device (1) 13 and the keyboard side extension device (2) 14 as a transmission current loop signal (SD-c) or a reception current loop signal (RD-c). Converted and transferred.

Here, for example, at the timing T0,
When the power of the computer main body 11 is cut off, the transmission data (SD-1) becomes a logic "0" of 0V, and accordingly,
The transmission current loop signal (SD) transferred from the main body side extension device (1) 13 to the keyboard side extension device (2) 14
-When c) becomes the logic "0" of current drive off, current /
The TTL signal output from the TTL conversion circuit 15 (TT
L) also becomes 0V logic "0".

The time after the power of the computer main body 11 is cut off is the transfer time of one word data (8 m
s), and when it is determined that the duration time t in which the TTL signal (TTL) is logic "0" has exceeded the predetermined time Dt (= 8 ms) by the time counting operation of the timer T in the break detection circuit 18, The break detection signal BR from the break detection circuit 18 is supplied to the relay circuit (R) 19, and the relay switch S thereof is turned off.

Then, the keyboard side extension device (2)
14 to keyboard 12 power supply line (+5
V-2) is shut off, and this causes the computer body 1
When the power supply of No. 1 is cut off, the power supply to the keyboard 12 is also cut off.

In this case, the breakage detection of the main body power supply in the break detection circuit 18 is carried out by judging that the logic "0" of the transmission data (SD-1) has continued beyond 1 word, so Break detection is not accidentally made during command data transfer.

Thus, the power supply of the computer main body 11 and the keyboard power supply line for the keyboard 12 (+ 5V)
-2) are both off, the computer system 11 is turned off at the time when the computer system is stopped, for example, at the timing T1, the data-free state in the initial state is the transmission data (SD-1). ) Logic "1" to the main body side extension device (1) 13, and the transmission current loop signal (S) from the extension device (1) 13 is given.
D-1) and T on the keyboard side extension device (2) 14
When both the TL signals (TTL) become the logic "1", the break detection signal BR supplied from the break detection circuit 18 to the relay circuit (R) 19 is turned off.

Then, the relay switch S in the relay circuit (R) 19 is turned on, and the power supply line (+ 5V-2) from the keyboard side extension device (2) 14 to the keyboard 12 is connected. Due to
When the power of the computer main body 11 is turned on, the keyboard 12 is also supplied with power.

Therefore, according to the computer system using the keyboard extension device having the above-mentioned configuration, the transmission / reception data (SD-1) of turning off / on the power source of the computer main body 11 is transmitted.
The keyboard side extension device (2) 14 detects the change based on the change of the keyboard power supply line, and the keyboard power supply line (+
Since the disconnection / connection of 5V-2) is controlled, the power supply to the keyboard 12 can be started / stopped at approximately the same time as the power supply to the computer main body 11 is started / stopped. Then, like before, power on /
It is possible to prevent the occurrence of malfunction due to the mismatch of OFF and the mismatch of operation modes.

[0036]

As described above, according to the present invention, the keyboard and the main body device operated by the keyboard are connected via the extension device, and the keyboard power supply is independent of the main body device power supply inside the extension device. In the extension device, the main body power supply detecting means for detecting power off / on of the main body equipment and the power off / on of the main body equipment detected by the main body power supply detecting means are provided. Since the keyboard power control means for controlling the turning off / on of the keyboard power provided in the extension device is provided, it is turned on between the main body side power supply and the keyboard side power supply,
It is possible to prevent occurrence of malfunction and inconsistency in operation mode without causing inconsistency in the off period.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a computer system using a keyboard extension device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a keyboard side extension device in a computer system using the keyboard extension device.

FIG. 3 is a timing chart showing a power control operation of a computer system using the keyboard extension device.

[Explanation of symbols]

11 ... Computer main body, 12 ... Keyboard, 13 ... Main body side extension device (1), 14 ... Keyboard side extension device (2), 1
5 ... Current / TTL conversion circuit, 16 ... TTL / RS2
32C conversion circuit, 17 ... RS232C / current conversion circuit, 18 ... Break detection circuit, 19 ... Relay circuit (R), 20 ... Power supply, T ... Timer.

Claims (2)

[Claims] 1. A keyboard extension device in which a keyboard and a main body device operated by the keyboard are connected via an extension device, and a keyboard power supply is provided in the extension device independently of the main body device power supply. In the apparatus, a main body power supply detecting means for detecting power off / on of the main body equipment, and a power supply for the main body equipment detected by the main body power supply detecting means are provided in the extension device. A keyboard extension device, comprising: a keyboard power control means for controlling the turning off / on of the keyboard power. 2. The keyboard extension device according to claim 1, wherein the main body power supply detecting means detects power off / on based on a change in data transmitted from the main body device to the keyboard.