JPS632195B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line concentrator connection system that connects a plurality of terminal devices and a line concentrator in a loop to enable data transfer with a simple configuration and control.

2. Description of the Related Art A data highway system is known in which terminal devices accommodating a plurality of terminal devices are connected in a loop, and data can be efficiently transferred between the terminal devices. In such a system, when a host computer is provided and data is transferred between each terminal device, the terminal device accommodating the host computer is provided with connection terminals equal to the number of terminal devices, making it relatively simple. Data transfer is possible with simple control. However, it is rare that all terminal devices transfer data at the same time.
Therefore, the number of vacant connection terminals increases, resulting in an uneconomical configuration. Furthermore, it is not possible to install more terminal devices than the number of connection terminals, resulting in a lack of expandability.

Therefore, it is possible to install a line concentrator to accommodate the host computer, but since there are various types of terminal devices, it is necessary to perform line concentrator connections corresponding to the type of terminal device, and the line concentrator can also select idle lines. This has the disadvantage that the configuration for concentrating the wires becomes complicated because the connection state must be memorized.

The present invention enables ordinary one-to-one communication by returning the channel address selected by the line concentrator to the calling party.
The purpose of this is to enable data transfer using simple control and configuration similar to that used in communication.
Examples will be described in detail below.

FIG. 1 is a block diagram of an embodiment of the present invention, in which terminal stations ST1 and ST2, line concentrator CST1,
A data highway system is configured by connecting CST2 in a loop through transmission line L, and terminal equipment
ST1 and ST2 have terminal devices DTE1a, DTE1b,
Concentrators CST1 and CST2 accommodate communication control devices CCP1 and DTE2b, respectively.
Accommodates CCP2, communication control devices CCP1, CCP2
It is connected to a host computer (not shown). In this embodiment, two terminal equipment ST
1 and ST2 are connected, but it is of course possible to connect more terminal devices, and the number of line concentrators can be one or more.

Terminal device DTE1a, DTE2a and terminal device DTE
1b and DTE2b are connected, the line concentrators CST1 and CST2 connect interface channel groups Ga, DTE2b corresponding to the types.
Gb.

For example, as shown in FIG. 2, the frame format sent to the transmission path L is a frame synchronization signal F,
It consists of a destination address field DA, a control information field C, a self address field SA, a header field H, a data field DATA, a frame check sequence signal FCS, and a frame synchronization signal F.

For example, from the terminal device DTE1a to the communication control device
When making a call to the host computer connected to CCP1, the terminal device ST1 calls the terminal device DTE1a.
Based on the call information from , the other party's address section DA,
The group address A ₁ that uniquely corresponds to the interface channel group Ga, and the self address section SA
A frame is formed in which an address _A2 uniquely corresponding to the terminal device DTE1a is added to the frame, and a frame is added to the control information C and connection request information, and the frame is sent to the transmission line L.

When the line concentrator CST1 receives this frame and identifies that it is addressed to its own station, it selects an empty channel in the interface channel group Ga based on the connection request information and the group address _A1 , and connects it to this empty channel. The uniquely corresponding address A ₃ is placed in the header section H of the frame, the address A ₂ of the calling terminal device DTE1a is placed in the destination address section DA, the group address A ₁ is placed in the own address section SA, and the control information section C A frame is formed by adding information representing an affirmative response to the connection request, and the transmission line L
Send to.

When terminal station ST1 receives this frame,
It is determined that the connection is completed using the channel corresponding to address _A3 in the line concentrator CST1.

If there is no empty channel in the interface channel group Ga, the line concentrator CST1 sends information indicating a negative response to the connection request to the control information unit C.
The address A ₂ of the terminal device DTE1a is placed in the other party's address section DA, and the group address A ₁ is placed in the self address section SA.
The pidgey notification is performed by forming and transmitting a frame with each .

The above operation is the line connection phase. Next, when the connection is completed, the process moves to the data transfer phase, and in the data transfer phase, the line concentrator CST1
Using the empty channel address A ₃ returned from
Transmission information is placed in the data portion DATA, and data transfer is performed under the same control as one-to-one communication.

If the terminal devices DTE1b, DTE2b of a different type from the terminal devices DTE1a, DTE2a originate a call, an empty channel of the interface channel section Gb is selected, and data transfer is otherwise performed in the same manner as described above.

FIG. 3 is a block diagram of an embodiment of the line concentrator, in which 1 is a reception interface section, 2 is an address decoding circuit, 3 is an address comparison circuit, 4 is an address storage circuit, and 5 is a time reception necessary for internal processing. A delay circuit for delaying information, 6 a selection circuit for selecting an empty channel based on a group address, 7 an information decoding circuit, 8 a transmission interface section for sending transmission information to a transmission path, 9 a response information generation circuit, 10a ~1
0n is a channel group, 11a to 11n are channel state detection circuits, 12a1 to 12al, 12n1 to 12
nm indicates channel.

Upon receiving a connection request from the terminal device, the group address A ₁ is transferred from the reception interface section 1 to the address decoding circuit 2. This group address _A1 consists of a node address and a channel group address, and the node address is the terminal station ST1, ST2 and line concentrator CST1, CST2.
The decoding result of this node address and the own station address stored in the address storage circuit 4 are used in the address comparison circuit 3.
The results are reported to the delay circuit 5, selection circuit 6, and information decoding circuit 7.

When the delay circuit 5 receives the comparison match signal from the address comparison circuit 3, the reception information added via the reception interface section 1 is sent to the transmission interface section 8.
will not be forwarded to. Further, when a comparison non-coincidence signal is received, the received information from the reception interface section 1 is delayed by a predetermined time and then transferred to the transmission interface section 8.

When the selection circuit 6 receives the comparison match signal from the address comparison circuit 3, the selection circuit 6 selects the interface channel groups Ga, Gb designated by the channel group address.
The channel state detection circuits 11a to 11n of the channel groups 10a to 10n belonging to the channel group 10a to 10n are notified. On the other hand, when the information decoding circuit 7 receives the comparison match signal from the address comparison circuit 3, it decodes the reception information transferred from the reception interface section 1, and when the connection request information is received, the channel status of all channel groups 10a to 10n is determined. The detection circuits 11a to 11n are notified. The channel status detection circuit that receives this notification and the notification from the selection circuit 6 scans the channels accommodated in it, and if there is an empty channel that can be connected based on the content of the status signal, it indicates the channel number and connection possible. The signal is transferred to the response information generation circuit 9. If there is no empty channel, the response information generation circuit 9 is notified that connection is not possible.

The response information generation circuit 9 is activated by a connection request information reception notification from the information decoding circuit 7, and responds to the contents of the notification from one channel status detection circuit, and if connection is possible, sends the address A using the notified channel number. ₃ to the header section H as described above, the information indicating that connection is possible to the control information section C, the address _A2 of the calling terminal device to the destination address section DA, and the group address _A1 to the own address section SA. The transmission interface section 8 forms a frame with
Transfer to.

In the data transfer phase, the address _A3 of the empty channel is sent from the calling side, so it is compared with each channel address stored in the address storage circuit 4 in the address comparison circuit 3, and if there is a match, the address A3 is sent to the delay circuit 5. stops the operation of transferring the received information to the transmission interface section 8, and the address decoding circuit 2
The selection circuit 6 uses the channel address decoded by
will specify the previously selected channel. Based on the selected channel, data is transferred between the terminal device and the host computer via the communication control device.

As explained above, the present invention provides a data highway system in which a plurality of terminal devices and a line concentrator are connected in a loop, from a terminal device housed in the terminal device to a host computer housed in the line concentrator. When making a call to a device such as, a group address is attached and a connection request is made, the concentrator selects an empty channel from the group of channels corresponding to the group address, and returns the channel address corresponding to this empty channel to the calling party. However, data transfer is performed using this channel address, and the line connection phase is based on software control, and the data transfer phase is based on hardware control, without reducing processing efficiency. This has the advantage of simplifying the hardware.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
The figure is an explanatory diagram of a frame format, and FIG. 3 is a block diagram of a line concentrator according to an embodiment of the present invention. ST1 and ST2 are terminal equipment, CST1 and CST2 are concentrators, L is transmission line, DTE1a, DTE1b,
DTE2a, DTE2b are terminal devices, CCP1, CCP
2 is a communication control device, and Ga and Gb are interface channel groups.

Claims (1)

[Claims] 1. In a data highway system in which a plurality of terminal devices and a line concentrator are connected in a loop, a device that is accommodated by a channel group consisting of a plurality of channels from the terminal device accommodated in the terminal device to the line concentrator. When making a call, the terminal device on the calling side sends the group address corresponding to the target channel group in the destination address field, the address of the calling terminal device in the own address field, and connection request information in the control information field. The concentrator on the called side selects an empty channel in the channel group corresponding to the group address and issues a channel address corresponding to the empty channel. A concentrator connection method characterized by transmitting data back to the calling side and using the channel address to transfer data between the calling side and the called side.