JPH01240055A - Terminal switching device - Google Patents

Abstract

PURPOSE:To eliminate the need for a hand at a field by switch-selecting either a terminal means for a remote place or another terminal means for the field when the terminal means becomes a transmitting state and holding the selected state until a communicating state is completed. CONSTITUTION:A first terminal means 1 is, for example, composed of a typewriter and a keyboard and provided in the field. A second terminal means 2 is provided in the remote place from a controller 4 and provided, for example, for a maintenance center, etc. Either an output signal from the first terminal means 1 or that from the second terminal means 2 is selected by a selecting means 3 and sent to the controller 4. The controller 4 is, for example, composed of an exchange, etc. The controller 4 sends information to inform the selecting circuit 3 and a selecting signal holding circuit 5 of the reception of the signal from either the terminal means 1 or the terminal means 2 through the selecting circuit 3 to the selecting circuit 3 and the selecting signal holding circuit 5. Further, the selecting signal holding circuit 5 holds the signal once selected by the selecting circuit 3. The holding of the signal is maintained while a state in which the signal from either the terminal means 1 or the terminal means 2, which is selected, is inputted to the controller 4 is continued.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a terminal switching device that selects one of a plurality of terminals and maintains input of a signal from the selected terminal, which requires on-site personnel. The purpose of the present invention is to enable switching between a local typewriter and a remote typewriter with a simple configuration without having to do so. 2
a selection circuit for selecting an output signal from either the first terminal means or the second terminal means, and a control device for receiving the signal selected by the selection circuit;
a selection signal holding circuit that holds the selection signal of the first terminal means or second terminal means to which the selected signal is sent when the control device receives the signal selected by the selection circuit; Configure it so that

[Industrial application field]

The present invention relates to a terminal switching device that selects one of a plurality of terminals and holds input of a signal from the selected terminal.

[Conventional technology]

As shown in FIG. 5, when a control device 11 such as a switchboard is maintained and operated using a typewriter 12 consisting of a keyboard or the like, a maintenance person is located near the control device 11 and performs the maintenance there. Recently, the need for centralized maintenance has increased, and by performing remote maintenance of the control device 11, maintenance operations are often performed using the typewriter 12 located remotely rather than from near the control device 11. It's here. However, even when performing remote maintenance, the typewriter 12 needs to be placed near where the control device 11 is located, that is, at the site.
are required to be installed both locally and in remote locations.

For this reason, as shown in FIG. 6, a switching device 14 is provided to switch between a local typewriter 12 installed near the control device 11 and a typewriter 13 installed at a remote location. The remote typewriter 13 is located, for example, at a maintenance center, and signals are transmitted via modems 15 and 16 and applied to the switching device 14.

A conventional example of this switching device 14 will be explained. In FIG. 7, a local typewriter 12 and a remote typewriter 1 are shown.
3 and 3 are manually switched by a switch SW using a switching device 17 including a switch SW. In this case, it is necessary to install the on-site typewriter 12 and the switching device 17 near the control device 11. Therefore, in order to operate the switch SW of the switching device 17, it is necessary to have someone on site or to use a special control line for switching instructions.

Further, as shown in FIG. 8, the local typewriter 12 and the remote typewriter 13 are connected to each other by a microprocessor unit (MPU) 181 and an asynchronous communication circuit (ACI).
There is also a method of switching using a switching device 18 such as 182.

That is, the local typewriter 12 is connected to the asynchronous communication circuit 182, the remote typewriter 13 is connected to the asynchronous communication circuit 183, and the control device 11 is connected to the asynchronous communication circuit 184. 181.3J1 step synchronous communication circuit 182゜183
and 184 are connected to each other via a bus.

(Problem to be solved by the invention) As in the conventional example shown in FIG. One possibility is to switch to the typewriter 12 side, but in this case, once switched to the local side, it would be impossible to operate from a remote location such as a maintenance center where there are highly skilled boat fishing technicians. turn into.

Therefore, when it becomes necessary to perform advanced operations from a remote maintenance center, etc., it is necessary to ask a person on site to switch to the remote typewriter 13, which reduces operability. It ends up.

In the example shown in FIG. 7, if a special control line is installed, one additional line is required in addition to the communication line, which increases the line cost.

In the system shown in FIG. 8, any switching processing can be performed by a program installed in the microprocessor unit 181 in the switching device 18, but there is a problem in that the amount of hardware increases and the cost becomes high.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to switch between a typewriter for on-site use and a typewriter for remote use without requiring on-site personnel and with a convenient configuration.

[Means to solve the problem]

FIG. 1 shows a diagram of the principle of the present invention. 1 is the first ÷: end means, which consists of a typewriter or keyboard, for example, and is installed at the site. 2 is a second terminal means and control f
It is located at a remote location from the f1l device 4, for example at a maintenance center.

One of the output signals from the first terminal means 1 and the second terminal means 2 is selected by the selection circuit 3, and the selected signal is sent to the control device 4. This control device 4 consists of, for example, a switching equipment.

The control device 4 sends, via the selection circuit 3, to the selection circuit 3 and the selection signal holding circuit 5, the fact that a signal from either the first terminal means 1 or the second terminal means 2 has been received. The selection signal holding circuit 5 is controlled to continue holding the selection signal of one of the first input terminal means 1 and the second terminal means 2 once selected by the selection circuit 3.

[For production]

A circuit 3 selects either the first terminal means 1 disposed locally or the second terminal means 2 disposed at a remote location.
When the selection is made, the selection state is transferred to the selection signal holding circuit 5.
held by. This retention is maintained as long as the signal from the selected terminal means I or 2 continues to be input to the control device 4. When the selection state from one terminal means is completed, the terminal means can be switched by selecting that a signal from another terminal means is input next.

(Example〕 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, a signal from a local typewriter 21 is received by a receiver 20 in a switching device 22. In FIG.

Similarly, the signal from the remote typewriter 23 is sent to the modem 2.
4 and 25 at the receiver 26. A multiplexer 27 selects the output signals of the receivers 23 and 26, and transmits the output signal of the multiplexer 27 to a control device 29 via a driver 28. When this control device 29 receives a signal from the driver 28 , it transmits a signal indicating this to a receiver 30 in the switching device 22 , and the output of this receiver 30 is applied to a demultiplexer 31 . The output of the demultiplexer 31 is transferred to the local typewriter 21 via the driver 32 or
via the modem 25.24 and applied to the remote typewriter 23. The output signals of the receivers 20 and 26 are applied to a priority selection circuit 34, which selects one output signal from the typewriter to be given the highest priority, and connects the resulting output to a selection signal holding circuit 35, which selects one output signal from the typewriter to be given the highest priority. Should keep the signal from the typewriter selected,
The selection signal holding circuit 35 controls the multiplexer 27 and the demultiplexer 31.

Further, the output of the receiver 30 is output from a timing signal circuit (TI
The ACT output of the priority selection circuit 34 and the output of the timing signal circuit 36 are applied to an AND circuit 37, and the output of this AND circuit 37 is applied as an enable signal to the selection signal holding circuit 35.

Local typewriter 21 and remote typewriter 23
When both lines are inactive, all lines have A polarity as shown in FIG. Here, A polarity is a no-communication state (recovery state). Both the typewriter 23 and the control device 29 maintain the transmission line at A polarity.

At this time, it is assumed that a command is input from the remote typewriter 23. The transmission line of the remote typewriter 23 changes to Z polarity, that is, start polarity transmission (start press). The priority selection circuit 34 allows the remote typewriter 2 to
Assume that the Z polarity signal from No. 3 is selected as the signal with priority.

The resulting output is applied to the selection signal holding circuit 35. This priority selection circuit 34 is a circuit that, when commands are input from a plurality of typewriters at the same time, selects a predetermined typewriter in order according to a predetermined priority order. Then, a signal indicating that the remote typewriter 23 has been selected by the selection signal holding circuit 35 is applied to the multiplexer 27, and a signal from the remote typewriter 23 is applied to the control device 29 via the driver 28. . Then, the control device 29 controls the typewriter 23 for remote location.
The control device 29 outputs a Z polarity signal indicating that it has received a signal from the control device 29 . That is, in FIG.
9 changes from A polarity to Z polarity, and thereby the transmission line of control device 29 changes from A polarity to Z polarity.

This Z polarity signal is applied to a demultiplexer 31 via a receiver 30. The demultiplexer 31 is connected to the remote typewriter 23 by the aforementioned selection signal holding circuit 35.
is configured to select the signal corresponding to
This signal is sent again to the remote typewriter 23 via the driver 33. This connects the remote typewriter 23 and the control device 29. At this time, the priority selection circuit 34 outputs an ACT signal, and the control device 29
A Z polarity signal is applied to the timing signal circuit 36 via the receiver 30. The operation timing of the timing signal circuit 36 is shown in FIG. In FIG. 4, when the input signal rises from the A polarity to the Z polarity, the output signal of the timing signal 36 becomes O, and the AND of the AND circuit 37 is not established and the enable signal becomes O. Therefore, the output signal of the selection signal holding circuit 35 is held as a signal for selecting the remote typewriter 23.

Activation of the control device from the typewriter will be explained in more detail with reference to FIG. When the remote typewriter 23 receives a command and changes to Z polarity, the receiving line of the control device 29 that receives the command changes to Z polarity, and then 210 to 4
90. Start detection is performed, and when this start detection is performed, a buzzer sounds in the interval typewriter 23. Then, between 470 and 490 ms, the controller 29
The side completes reception preparations and lights up the communication lamp. and,
Change the transmission line from A polarity to Z polarity. Then, the reception line of 23 typewriters changed from A polarity to Z polarity,
After 210 to 490 ms have elapsed, activation confirmation detection is performed on the typewriter 23 side, and the communication lamp there is turned on.

Next, the operation of the timing signal circuit 36 will be specifically explained with reference to FIG. When the input signal changes from Z polarity to A polarity and a predetermined time elapses, an output signal is generated, and the AND
Since the enable signal is output from the circuit 37, the output signal of the selection signal holding circuit 35 is not held at a constant value, and each signal flows in a through state as the input signal changes. This predetermined time t is a value longer than the long space in the transmitted character, -a is 200
It is assumed to be about ms. That is, if the Ai state continues for more than this predetermined time, it means that the Z polarity has changed to the A polarity, which is a non-communication state, so the timing signal circuit 36 generates one signal as an output signal. Then, when the connection state with the typewriter 21 or 23 is established, the Z polarity signal is generated from the control device 29, so at this time, the output signal of the timing signal circuit 36 immediately becomes the O signal, and therefore the enable signal is stopped. That will happen.

Note that the A polarity signal is O, space, on, or +8.
V, and the Z polarity signal is 1, mark, off, or -
This corresponds to 8■.

〔Effect of the invention〕

According to the present invention, with a simple configuration, when a remote typewriter or a local typewriter enters a transmitting state, the typewriter is switched and selected, and the selected state is maintained until the communication state ends. be able to.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a diagram showing a procedure for starting the control device from the typewriter in the embodiment of Fig. 2, Fig. 4 is a timing diagram showing the operation of the timing circuit in the embodiment shown in Fig. 2, Fig. 5 is a block diagram showing an example where the typewriter is installed near the control device, and Fig. 6 is a timing diagram showing the operation of the timing circuit in the embodiment shown in Fig. 2. A block diagram showing an example of installation in a remote location. Figure 7 is a block diagram of a conventional switching device that switches switches manually. Figure 8 is a block diagram of a conventional switching device that switches switches using a microprocessor. be. DESCRIPTION OF SYMBOLS 1... First terminal means, 2... Second terminal means, 3... Selection circuit, 4... Control device, 5... Selection signal holding circuit,

Claims (1)

[Claims] A first terminal means (1) for inputting a signal, a second terminal means (2) for inputting a signal, and the first terminal means (1) and the second terminal means ( 2); a control device (4) that receives the signal selected by the selection circuit (3); and the control device (4) is the selection circuit. When the signal selected by (3) is received, the first terminal means (1) or the second terminal means (1) to which the selected signal is sent.
2) A terminal switching device comprising a selection signal holding circuit (5) that holds the selection signal of item 2).