JPS6273839A - Logical multiplex system - Google Patents

Abstract

PURPOSE:To allow plural secondary stations connected to one multi-drop line to a different primary station by corresponding a polling/section address recognized by the primary station to a polling/section address decided independently on the multi-drop line by a PAD. CONSTITUTION:When a CPU 9 sends a polling signal, the PAD 15 converts it into a packet signal and informs it to a PAD 17. the PAD 17 uses address information to recognize it to be a polling signal to a terminal device 13, the address part of the polling signal is converted into an address of the PAD 17 and the result is sent to a multi-drop line 8. A terminal device 11 recognized it as the polling addressed to itself depending on the value of the address part and returns a proper reply signal. When the PAD 17 receives a response signal via the multi-drop line 8, the address part is converted into the address of the terminal device 13 viewed from the CPU 9 to combine the packet, the result is sent to the PAD 15, which sends it to the CPU 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a system for accommodating non-packet type terminals to a packet-switched network, and in particular to a method for accommodating non-packet type terminals in a packet-switched network. Regarding the method.

[Background of the invention]

Conventionally, non-packet type terminals that use multi-drop lines to perform bowsong or selexicon control procedures have been connected to a packet-switched network as shown in FIG. In Fig. 1, 1 is a central processing unit (CPU) which is a primary station in the transmission control procedure, 2 to 4 are terminals which are also secondary stations, 5 is a packet switching network, and 6 and 7 are packet assembly units. 8 indicates a disassembly function (PAD) and a multidrop line connecting terminals 2 to 4.

In FIG. 1, the bow song or select signal sent from CPU 1 is PAD7. Packet switching network 5
, terminal 2 via PAD 6 and multidrop line 8.
~ Sent to 4. The corresponding terminal learns this from the address part of the polling or select signal, and returns a response signal to the CPU 1 via the reverse path as described above. That is, P.A.D.
6.7 and the packet exchange N45, the polling/mole2f1f procedure is executed as if the points A and B shown in FIG. 1 were directly connected. According to the above-mentioned prior art, PAD7. Since packet switching [5, PAD6 operates as if it were one line connecting (:pu1 and multidrop line 8, CI'U,1
That is, the multi-drop lines 8 are required in one-to-one correspondence to the primary station, and correspondingly, a connection port of PAD 6.7 is required in the packet switching network 5.

Note that the transmission control procedure involving polling or selection includes a data link control procedure or a basic procedure. Further, as a technology related to this field, there is a technology described in %Kokai No. 54-64407.

[Purpose of the invention]

An object of the present invention is to provide a system for connecting secondary stations, which has conventionally been necessary depending on the number of secondary stations.

[Summary of the invention]

The present invention is different in order to achieve the above-mentioned objectives.

A logical multiplex system of PA and D is provided that connects the secondary station communicating with the next station to one multidrop line to enable A communication. According to the present invention, each leakage connected to one multidrop line is different. : It becomes possible to communicate with station B.

The present invention enables PAD to connect a single multidrop line by associating the polling/molexic address recognized by the primary station with the polling/molexic address independently determined on the multidrop line. It is characterized by a logical multiplexing system that allows multiple secondary stations to communicate with different primary stations.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 is a close-reading configuration diagram showing one embodiment of the present invention.
Tamesue is a 3Vi secondary station, and 14 is Bakekto! ! 4 network, 15-17 PAD, Ma.

8 indicates a multidrop line. In Figure 2, CP
U9 is connected to terminal 11.12, and CPU10 is connected to terminal 15.
shall communicate with each other.

FIG. 6 is a flowchart showing the operation of the PAD 17 accommodating the multidrop line 8.

In this embodiment, - the next station (:PU9゜CP
[The operations of PAD14 and PAD16, which respectively accommodate NO, are the same as PAD7 in FIG. Further, in this embodiment, the CPU 9 communicates only with the terminals 11 and 12, and the CPU 10 communicates only with the terminal 15. CPU
The addresses of terminals 11 and 12 as seen from 9 are 1, respectively.
2. The address of terminal 13 seen from cptyio is 1
．． Further, the addresses of the terminals 11, 12, and 15 as viewed from the PAD 17 are assumed to be 11, 12, and 13, respectively.

First, the operation when the CPU 9 sends the terminal 11iC polling signal will be explained. When the CPU 9 sends out a polling signal, the PAD 15 converts it into a packet signal and notifies it to the FAI'17. The address of the polling signal carried by this packet is the address of the terminal 11 as seen from the CPU 9! 1 is set as the information. P.A.
Is D 17 the relevant packet? When received, it knows from the address information that it is a polling signal for the terminal 13, converts the address part of the polling signal to 11, which is the address seen from the PAD 17, and sends it to the multidrop line 8. When the terminal 11 receives the corresponding signal, it knows from the value of the address field that it is addressed to itself, and returns an appropriate response signal.

11 is set in the address part of this response signal.

When the PAD 17 receives the response signal via the multi-drop line 8, it converts the address S to 1, which is the address of the terminal 15 seen from the CPU 9, assembles a packet, and sends the PADf
Send to 5. When the PAD 15 receives the corresponding packet, it sends it to the CPU 9.

The process of sending a polling signal from the CPU 9 to the terminal 11 and receiving a response from the terminal 11 has been described above, but the same applies to the selection signal. Also, from CPU9 to terminal 12
Even when sending a polling signal or selection signal from the CPU 10 to the terminal 13 and receiving a response b in response, communication is performed by converting the address as shown in 70-Tayat in Figure 3. I can do it.

Note that when packets arrive at the PAD 17 from the PADs 15 and 16 at the same time, one of the packets is processed first, that is, after a polling signal or selection signal is sent out and a response is obtained, the remaining packets are processed one after another.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of primary stations can be used as communication partners between secondary stations connected to one multidrop line, and two or more primary stations can be connected to a multidrop line. It is possible to logically multiplex communication with Therefore, according to the present invention, it is possible to reduce the number of multi-drop lines accommodated in the PAD between secondary channels compared to the conventional system, and also to reduce the number of PAD ports in the packet switching network, resulting in an economical communication system. It becomes possible to construct

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional system, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is a PAD1 in Fig. 2.
70-chart showing the operation of No. 7. 1.9.10...Central processing unit (CPU) 2 to 4.1
1-13...Terminal, 5,7.15-17...Packet assembly and disassembly function (P
AD) 8 multi-drop line agent patent attorney Katsuo Ogawa, 6 (1,... 1st Figure 3 Father)

Claims (1)

[Claims] In a packet switching network that uses a packet assembly and disassembly function to accommodate multiple primary stations that perform polling or selection and secondary stations that communicate with these primary stations, multiple secondary stations that communicate with different primary stations are connected to a single line. By making a drop connection, the packet assembly and disassembly function associates the polling or selection address recognized by the primary station with the polling or selection address independently determined on the multidrop line.
A logical multiplexing system characterized by allowing a plurality of secondary stations connected to one multidrop line to communicate with different primary stations.