JPH0440138A - Ring-type lan - Google Patents

Abstract

PURPOSE:To enable speedy recovery when generating a fault by recovering the fault by the fault recovering function of a packet exchange type LAN connection part when the fault is generated in plural communication stations or transmission lines. CONSTITUTION:The slave station detecting abnormality does not repeat a transmitted frame Fs but generates an individual frame and forcedly transmits this frame synchronously with a clock, to which crystal oscillation is executed in a packet exchange type LAN connection part 4, by a transmission control part 27. At such a time, for this frame, only the symbol encoding a frame/token bit train F/TBA to be outputted from the packet exchange type LAN connection part 4 is inserted to the relevant slot. Afterwards, the fault is recovered by the fault recovering function provided in the packet exchange type LAN connection part 4, and a network is constructed again.

Description

Detailed Description of the Invention "Field of Industrial Application" This invention relates to a ring type LA in which a plurality of communication stations are connected in a ring shape through a transmission path and data communication is performed between these stations.
Regarding N (local information communication network).

"Conventional technology" Traditionally, when playing songs and producing music sources in a music production studio, audio data that is digitally converted from voices and sounds generated from acoustic instruments, and audio data generated from electronic instruments such as synthesizers are used. Performance control data expressed by key-on signals, key-off signals, etc., are handled separately.

This is based on the reasons shown below.

First, performance control data, such as key-on signals and key-off signals, can be transmitted by sending a signal of a predetermined length at the time each signal is generated, so packets have traditionally been used to transmit computer data. Replaceable LA
N can be used as is. Therefore, only one communication cable is required.

On the other hand, for chronologically continuous data such as audio data, data of a predetermined length, for example, 24-bit data, must be continuously sent at predetermined sampling timings.

This is not a problem when the transmission speed is sufficiently high and the amount of data is small, but it becomes a problem when multiple lines are overlapped. Therefore, a dedicated line is required for each audio data, and in the past, communication cables for audio data were required for the number of sources or more.

Recently, music production software that can directly handle not only performance control data but also audio data has begun to appear.

Furthermore, in recent years, multimedia has come into the spotlight. Multimedia is a technology that associates and synchronizes commands that can be processed by conventional computers, such as numerical values, characters, and graphics, with time-series continuous stream data such as audio data and video data. By using this multimedia in a computer, images and sounds can be added to the computer, providing individuals with a sense of realism and ease of use that cannot be achieved with books or television. In the case of this multimedia as well, it is necessary to be able to simultaneously communicate commands and stream data.

In view of the various situations described above, it is desirable to be able to communicate both a variety of stream data, typified by audio data, and commands, typified by performance control data, in real time and without delay over a single LAN.

Incidentally, the command transmission speed in a bucket-switched LAN has conventionally been about 4 to 1 Q M bps, and the transmission speed of stream data, especially video data, has to be about 100 M bps. Furthermore, although the transmission speed of audio data is relatively low, the tolerance for transmission delay is extremely small. In this way, stream data has various properties different from those of commands.

Therefore, in order to communicate commands and stream data with different properties through one LAN, the following method can be considered.

(1) This is a method in which multiple protocols are superimposed using frequency division multiplexing. That is, one transmission path having a certain frequency bandwidth is divided into a plurality of frequency bands, channels are assigned to each frequency band, and commands or stream data are transmitted using a different protocol for each channel. For example, commands are transmitted using a certain protocol in a channel with a frequency band of 1 to 100 Hz, and stream data is transmitted with a different protocol in a channel with a frequency band of 101 to 200 Hz.

(2) A method of communicating stream data and commands by time division multiplexing. That is, circuit switching and bucketing according to the type of data on one transmission path.

This is a method that performs card exchange at the same time.

(3) This is a method that uses ATM (asynchronous transmission mode) to handle stream data and commands using the same protocol. In this method, audio data, video data,
All commands and the like are broken down into fixed-length blocks called cells and transmitted over a transmission path.

``Problems to be Solved by the Invention'' Now, in the conventional LAN described above, when a failure occurs such as a transmission line disconnection or a failure of each communication station that controls communication, communication is interrupted. It is necessary to detect these failures as quickly as possible and restore them immediately.

By the way, circuit-switched LAN and bucket-switched LA
Each of N has a failure recovery function, so that stream data and commands can be communicated without any trouble.

However, stream data and commands are stored in one LA.
In each of the above-mentioned methods (1) to (3) that communicate using
The drawback was that it was not possible to communicate over one LAN.

Another drawback is that when a failure occurs, it is not possible to recover immediately.

This invention was made in view of the above-mentioned circumstances, and allows stream data and commands to be communicated over a single LAN with a simple configuration and protocol without reducing communication efficiency, and in addition, when failures occur. in case of,
The purpose is to provide a ring-type LAN that can be restored immediately.

"Means for Solving the Problem" The present invention provides a ring type L system in which a plurality of communication stations are connected in a ring shape through a transmission path and data communication is performed between these stations.
In the AN, the plurality of communication stations have a failure recovery function, transmit packet data to other stations via a transmission path, and receive packet data transmitted via a transmission path using a packet-switched LAN connection. and a circuit-switched L that transmits stream data to other stations via a transmission line and receives stream data transmitted via a transmission line.
If a failure occurs in the plurality of communication stations or the transmission path, the failure recovery function of the packet-switched LAN connection unit recovers from the failure.

"Operation" According to the present invention, in a communication station, packet data is transmitted to another station via a transmission path by a packet-switched LAN connection section, and stream data is transmitted via a transmission path by a circuit-switched LAN connection section. transmitted to other stations via

On the other hand, in other communication stations, packet data sent via the transmission path is received at the packet-switched LAN connection, and stream data sent via the transmission path is received at the circuit-switched LAN connection. Received.

As a result, packet data and stream data are
The data can be transmitted using two LANs.

If a failure occurs in a certain communication station or transmission path, the failure is recovered by the failure recovery function of the packet-switched LAN connection section.

"Embodiment" Before describing an embodiment of the present invention, the basic idea for solving the above-mentioned problem will be explained.

The present applicants have previously jointly and independently proposed a token ring based packet-switched LAN for real-time applications.

Here, the configuration of the packet-switched LAN connection section used in the above-mentioned bucket-switched LAN and controls the transmission and reception of signals will be described.

FIG. 5 is a block diagram showing the configuration of a packet-switched LAN connection section and its peripheral devices. 1 is a connector connected to a transmission line such as an optical fiber cable, and 2 is a receiver which receives signals transmitted via the transmission line and connector 1 and outputs a 1-bit width signal S□.

Further, 3 is a decoding unit, which converts the signal S pa into a frame/
While decoding the token bit string F/TBA, the internal PLL circuit section extracts the bit clock CKa from the signal S□ and outputs it.

Furthermore, 4 is a packet-switched LAN connection section. In the packet-switched LAN connection unit 4, 5 is a received bit analysis unit that constantly inspects the frame/token pit string F/TBA and detects timing signals STN regarding the start/end of the frame/token bit string F/TBA. ,
Detection and generation of ring priority P and reservation priority R, and extraction of frame bit string FBA constituting the frame are performed. Here, the ring priority P is the current priority of the token or frame transmitted on the transmission path, and the reservation priority Rt is used by the communication station to reserve data transmission according to the priority of data within its own station. This is the priority used for

Reference numeral 6 denotes a reception control unit which inputs the frame bit string FBA, judges whether or not this frame bit string FBA is addressed to the local station, and outputs received data D6 addressed to the local station. 7 inputs the received data DIl, and processes the received data D based on a reception control signal RCTL output from a data processing section (not shown).
This is a received data output section that outputs 8.

8 is a bit delay unit that rewrites bits while relaying the frame/token bit string F/TBA, and 9 is a transmission data input unit, which performs data processing by inputting a transmission control signal TCTL to a data processing unit (not shown). It inputs transmission data DT to be transmitted outputted from a transmission control section 10, and outputs transmission data DT based on a data request signal DR outputted from a transmission control section 10, which will be described later.

Reference numeral 10 denotes a transmission control unit, which generates a token bit string TBA and also sends a data request signal DR to the transmission data input unit 9 based on the transmission instruction signal TS and transmission end signal TE output from the transmission data input unit 9. By outputting, the transmission data D is input, a frame bit string FBA is generated, and the generated frame bit string FBA is output according to the token ring protocol.

This frame bit string FBA is generated by transmitting data DT
This is performed based on the data priority P extracted from the data priority P, the ring priority Pr output from the received bit analysis section 5, the reservation priority R, and the timing signal STM.

Reference numeral 11 denotes a transmission reservation unit, which inputs the larger of the reservation priority R, outputted from the transmission control unit 10 and the data priority P, and outputs a value corresponding to the priority to the bit delay unit 8. Frame/token bit string being passed F/T B
A's reservation index beep) Set to Rr. 12 is a frame/token bit string F/TBA output from the bit delay section 8 and a frame/token bit string F/TBA output from the transmission control section 10.
This is a transmission selection unit that selects and outputs either one of the token bit strings F/TBA. Note that this selection is performed based on the selection signal S GEL output from the transmission control section 10.

In addition, 13 is a frame/token sequence F output from the transmission selection unit 12 of the packet-switched LAN connection unit 4.
14 is an encoding unit 13 that encodes /T BA.
This is a transmitter that inputs the output signal SPT of and transmits a signal SP7 to another communication station via a transmission path.

For details of the above-mentioned packet-switched LAN, please refer to the specifications and drawings attached to the respective applications of Japanese Patent Application No. 1-342291 to Japanese Patent Application No. 1-342295 and Japanese Patent Application No. 1-343211. .

By the way, the packet switching type LAN connection section 4 mentioned above is
Since it can be configured using an SI (large scale integrated circuit), commands can be easily communicated by using this LSI in a packet-switched LAN.

Therefore, in the present invention, command communication is performed using the packet-switched LAN connection section 4 described above, and the LAN for communicating commands and stream data is
The LAN uses a hybrid type protocol of a line-switched protocol for stream data and a bucket-switched protocol for commands.

Next, the topology of the LAN is the packet-switched L
Due to the use of the AN connection section 4, it is of a ring type. Furthermore, the transmission method is a baseband transmission method.

There are two ways of thinking about hybridization as shown below.

The first idea is to put packet-switched LAN data on a circuit-switched LAN channel. first,
This circuit-switched LAN protocol provides N channels that allow one-to-many (or one-to-one) communication.

Therefore, N independent stream data can be handled. Furthermore, as shown in FIG. 6, it is assumed that the stream data is transmitted using a frame having N slots and l- corresponding to N channels.

Then, each transmitting station divides and inserts stream data into preset slots among the N slots of each frame, and time-division multiplexes this frame with sufficient timing to transmit the stream data. to be transmitted periodically.

On the other hand, each receiving station assembles stream data for that channel by connecting the /ports in the same numbered slots of each frame.

This allows data transmission by creating one channel for one stream of data. For example, in FIG. 6, slot 1 of frame 1
By connecting the data in slot 1 of frame 2 with the data in slot 1 of frame 2, the stream data of channel 1 is assembled, and by connecting the data in slot 2 of frame 1 with the data in slot 2 of frame 2, the stream data of channel 2 is assembled. stream data is assembled.

Furthermore, data in a packet-switched LAN is transmitted by being divided and inserted into the slots of each frame.

Thereby, commands and stream data can be transmitted through one transmission path.

Here, FIG. 7 shows an example of the configuration of a control section for signal transmission and reception based on the first concept. In this figure, 1 is a connector, 4 is the above-mentioned packet-switched LAN connection section, and 15 is a circuit-switched LAN connection section that is used for a circuit-switched LAN and controls the transmission and reception of signals.

The second idea is to combine circuit-switched LAN data and packet-switched LAN data into one data. Here, an example of each data encoding method is shown below.

000: O-level data of circuit-switched LAN 001: Level data of circuit-switched LAN 010: O-level data of packet-switched LAN 011: Packet-switched LAN
Therefore, by encoding circuit-switched LAN data and packet-switched LAN data using the same encoding method, it is possible to overlap each data and transmit it as one data. At the same time, it is also possible to separate each piece of data from the superimposed data.

Here, FIG. 8 shows an example of the configuration of a data transmission/reception control section based on the second concept. In this figure, parts corresponding to those in FIG. 7 are given the same reference numerals, and their explanations will be omitted. In FIG. 8, 16 is a shunt/combiner, which separates the signal transmitted via the connector 1 into a signal for the packet-switched LAN and a signal for the circuit-switched LAN, and also connects the packet-switched LAN. The signals output from each of the section 4 and the line-switched LAN connection section 15 are combined and transmitted as one signal via the connector 1. Note that the circuit-switched LAN connection section 15 in FIG. 8 may have a different configuration from the circuit-switched LAN connection section 15 in FIG. 7.

By adopting the above-described concept, stream data and commands such as musical tone control data can be communicated over one LAN with a simple configuration and full protocol without reducing communication efficiency.

(1) Explanation of the first idea The stream data encoding method is N RZ I (
Non Return to Zero Inve
rted) and 4B, which represents 4 bits of data in 5 bits.
15B encoding method. FIG. 9 shows an example of the encoding method described above. In this figure, + indicates that the polarity is reversed, and - indicates that the polarity is not reversed.

In FIG. 9, (0) to (F) are symbols for data, and (BST) to (FE) are synchronization symbols for frames, which are used to find the frame. still,
The structure of the frame will be described later with reference to FIG. 10. Further, (NC) to (OV) are synchronization symbols for data of each slot.

In FIG. 9, (reservation) means that there is no particular use in mind at the moment, or that it has been reserved for future use.

Next, the structure of a frame sent between each communication station will be explained using FIG. 10. The frame is of fixed length, starting with a frame start synchronization symbol (FS), followed by N slots (corresponding to N channels), and ending with a frame end synchronization symbol (FE). A preamble (PRA) is inserted between frames.

Furthermore, the size of one slot is one symbol, and this slot contains data symbols from (0) to (F) mentioned above, and a symbol indicating that there is no data in the slot (hereinafter referred to as a no data symbol). ) (NC),
A sample synchronization start symbol (C8), a data error symbol (ER), and a non-data symbol of the overflow symbol (OV) of the 4M sofa are entered. In addition, at each receiving station, when the symbols in the slots with the same number of each frame are connected, it becomes, for example, 24-bit (y) audio data, but since it is necessary to synchronize this data, the above-mentioned Non-data symbols (NC) to (OV) are used for data synchronization.

As mentioned above, by encoding the symbols used for data synchronization together with the data, data synchronization symbols (NC) to (○■) can be used at the same level in frames and channels, improving communication efficiency. The circuit configuration becomes simpler as there is no need to further decode data and synchronization data from these symbols.

Next, the representation of audio data, which is stream data obtained by connecting symbols in slots with the same number of frames, will be described. FIG. 11 shows an example of the format of audio data. The above-mentioned sample synchronization start symbol (C8) indicates the separation of each sample, and six data symbols (Do-D5)
) by 24-bit PCM (Pulse C
ode Modulation) value. The no data symbol (NC) may be placed anywhere in the symbol string, and is used to adjust the speed of regularly transmitted slots and the speed of irregularly generated audio data.

Also, musical tone control data is considered as packet-switched LAN data, which is another data obtained by connecting the seven holes in slots of the same number in a frame. Like the audio data, this data is also decoded from symbols in specific slots (described later) of the frame based on the encoding method described above. As in the case of audio data, one data symbol represents a 4-bit signal. A no-data symbol (NC) may be placed at the end of the symbol string, and is used to adjust the speed of the slot and the speed of the musical tone control data.

In addition, the data of the packet-switched LAN includes musical tone control, etc.
It is also used for ring failure recovery. When the packet-switched LAN bus enters a forced transmission state due to a ring abnormality, the communication station stops repeating frames and enters a forced transmission state of frames carrying only the channel corresponding to this data. The data of the packet-switched LAN is also used for maintenance such as channel assignment in the circuit-switched LAN. In addition, packet-switched LA
For details on the format and usage of the N data, please refer to the specification and drawings attached to the above-mentioned Japanese Patent Application No. 1-342291.

By the way, unlike audio data, packet-switched LAN data is originally something that is repeated by each communication station on the LAN, so all communication stations use the same assigned slot (channel) to transmit and receive data. It is necessary to repeat the data. Although this repeat processing causes a delay of at least one frame at each communication station, the delay can be kept to a minimum by assigning a plurality of slots, l-, to data in the packet-switched LAN.

An example to which the first concept is applied will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a ring-type LAN according to an embodiment to which the first concept is applied. In FIG. 1, 17 and 174 are communication stations that perform data communication with each other, and the communication stations 17. is a mask station and communication station 1 that periodically transmits and collects frames.
7! 174 are slave stations that perform reception processing and transmission processing while repeating frames. 18 is communication station 1
7. This is a transmission path such as an optical fiber cable that connects 174 to 174 in a ring shape.

Here, FIG. 2 shows a block diagram of the configuration of the communication station 17 of FIG. 1. In this figure, 1 is a connector, and 19 is a frame F having the format shown in FIG.
15 is the above-mentioned circuit-switched LA, N connection section, and 4 is the above-mentioned packet-switched LA.
N connection section 21 is a musical tone control data processing section, which processes the musical tone control data D output from the packet-switched LAN connection section 4 and the musical tone control data DT to be transmitted to another communication station 17. conduct.

In addition, 22 is an audio data processing unit, and the audio data DAR outputted by the line-switched LAN connection unit 15 is
and processing of audio data DAT to be transmitted to other communication stations 17. Reference numeral 23 denotes an encoding unit that encodes the frame Fs outputted from the circuit-switched LAN connection unit 15 into a transmission signal and transmits it via the connector l and the transmission line 18.

Furthermore, in the circuit-switched LAN connection section 15, 24 is a reception control section, which extracts symbols from the audio data slot assigned to its own station and the packet-switched LAN slot of each input frame Fs, and replaces them with In addition to inserting no data 7 symbols (NC) into
A symbol string is generated for each slot 7), and a symbol string S PR and audio data DA are generated for the bucket/node exchange type LAN.
It is divided into R (see FIG. 11) and output. Of these, the audio data DAR is output after waiting for the sample start synchronization symbol (C3), as shown in FIG.

3 is a decoding unit which converts the input symbol string SPR into a frame/token bit string F/T of a packet-switched LAN.
Decode to BA and clock OK! Output in synchronization with l.

Reference numeral 13 denotes an encoding unit, which encodes frames/frames output from the switching type LAN connection unit 4 in synchronization with the CKT.
Input token bit string F/TBA and generate symbol string SP
It is encoded into T and output. 27 is a transmission control unit which inputs the audio data D AT and the symbol string SPT output from the encoding unit 13, and sends these to the reception control unit 2.
The frame F8 is inserted into a predetermined slot of each frame F8 output from F4 and output.

Here, the total number of slots per frame is 1
There are five slots, and the allocation of each slot is determined in advance as follows.

(1) Audio data transmission slot 1: mask station 17. - Slave station 17° slot 2 Nislep station 17. -Slave station 17° slot 3
．． Slave station 17. → Slave station 17° slot 4 Slave station 174 - Master station 17° slot 6: Mask station 17I → Slave station 17° slot 7 Mask station 17.
- Slave station 174 slots 9 Nislep station 17. →Master station 17I slot 10. Slave station 17. →Slave station 17° slot 11 Slave station 17. - Master station 17° slot 13. Slave station 17. -Slave station 1
7° slot 14/slave station 17. -Slave station
7゜Slot 15 Nislepe station 174-Slave station 17
(2) Slot for transmitting musical tone control data 5. ,．． 8.12 In such a configuration, the operation of each communication station 171 to 174 to communicate audio data and musical tone control data will be explained.

First, mask station 17. In the bucket/soto exchange type LA
Based on the output timing of the transmission control signal TCTL output from the transmission data input section 9 (see FIG. 5) of the N connection section 4, musical tone control data such as a key-on signal is sent from the musical tone control data processing section 21 (see FIG. 1). DT is output and input to the transmission data input section 9 of the packet-switched LAN connection section 4.

Next, in the packet-switched LAN connection section 4, a frame/token bit string F is generated based on the musical tone control data DT.
/TBA is generated, this frame/token bit string F/TBA is output in synchronization with the output clock CKT of the packet-switched LAN connection section 4, and is sent to the encoder 1.3 of the circuit-switched LAN connection section 15. (second
(see figure). For details of the operation of the switchable LAN connection section 4, please refer to the specification and drawings attached to Japanese Patent Application No. 1-342291.

The frame/token bit string F/TB is then encoded into a symbol string SpA by the encoding section 13 based on the encoding method shown in FIG. 9, and then input to the transmission control section 27.

Next, the symbol string SPT is divided and inserted into slots 5.8 and 12 of each frame F5 generated by the transmission control unit 27.

On the other hand, the 24-bit audio data DAT encoded in the audio data processing section 22 is sent to the slave station 17. The audio data to be transmitted to slave station 17. is transmitted in slot 1 of each frame F. Audio data to be transmitted to slave station 174 is divided and inserted into slot 6, and audio data to be transmitted to slave station 174 is inserted into slot 7, respectively.

Since slots 2-4, 9-11 and 13-15 of each frame F5 are used by other slave stations 17°-174, no data symbols (NC) are inserted.

Frame F5 in which symbols have been inserted into each slot in this way is output from the transmission control section 27 and sent to the encoding section 2.
After being encoded into a transmission signal at 17.3, it is sent to the slave station 17. ~174 periodically.

Next, slave station 17. In the decoding section 19 , a frame Fs is decoded from the signal transmitted via the transmission line 18 and the connector 1 , outputted, and inputted to the line-switched LAN connection section 15 .

Then, in the reception control unit 24, the symbol of the slot assigned to the own station regarding audio data, in this case, slot 1, is extracted from slots 1 to 15 of each input frame F5, and the symbol of the slot 1 is extracted. A no data symbol (NC) is inserted into slot 1.

Further, the extracted symbols are stored one after another in the internal memory of the reception control section 24, and then outputted as audio data DA+t in synchronization with the sample synchronization symbol (CS).

Further, in the reception control unit 24, the symbols divided and inserted into slots 5, 8 and 12 regarding the musical tone control data of each frame F5 are taken out, and the no data symbols (NC ) is inserted.

Further, the extracted symbols are connected and sequentially output as a symbol string SP□.

Next, the symbol string S□ is decoded into a frame/token bit string F/TBA in the decoding unit 3, and then outputted in synchronization with the clock CKR, and is sent to the bucket exchange type LAN.
It is input to the connection section 4.

At this time, if no data symbols (NC) are inserted in slots 5, 8, and 12 of each frame, that is, if information regarding musical tone control data is not transmitted from the mask station 171, the decoding unit 3, the clock CK3 is not output.

Therefore, the frame/token bit string F/TBA is not input to the packet-switched LAN connection section 4.

When the frame/token bit string F/TBA is input to the packet-switched LAN connection unit 4, the received bit analysis unit 5 (fifth
(see figure), frame/token bit string F/T
A frame bit string FBA constituting a frame of a bucket-switched LAN is extracted from BA. Next, in the reception control unit 6, the frame/token bit string F/T
Received data D3 is extracted from B and is input to the received data output section 7. This received data DR is outputted from the received data output section 7 based on the reception control signal RCTL outputted from the musical tone control data processing section 21, inputted to the musical tone control data processing section 21, and processed.

Here, slave station 17. If it is time to acquire a token and send musical tone control data,
Based on the transmission control signal TCTL output from the transmission data input section 9 of the packet-switched LAN connection section 4, musical tone control data processing section 21 outputs musical tone control data DT,
The data is input to the packet-switched LAN connection section 4.

Next, the packet-switched LAN connection section 4 generates a frame bit string FBA based on the musical tone control data DT, and then outputs it in synchronization with the output clock CKT to the line-switched LAN connection section 15 (see FIG. 2). ).

Also, slave station 17. frame, or
When the token is simply repeated, the packet-switched LAN connection unit 4 outputs the repeated frame/token bit string F/TBA in synchronization with the output clock CK, and the packet-switched LAN connection unit 4 outputs the repeated frame/token bit string F/TBA in synchronization with the output clock CK. 15 (see Figure 2).

And frame/token bit string F/T B9
is encoded into a symbol string SP by the encoding unit 13 and then input to the transmission control unit 27 .

Next, the symbol string 5P-7 is divided into slots yh5, yh8 and yh12 of each frame Fs and inserted in the transmission control unit 27.

On the other hand, if it is not the timing at which the frame/token bit string F/TBA is output at the slave station 17t, the output clock CKT is not output from the packet-switched LAN connection section 4.

Therefore, since the symbol sequence SPT is not output from the encoding unit 13, the transmission control unit 27
, no data symbols (NC) remain inserted in slots 5.8 and 12 of .

Also, slave station 17. Audio data D to be transmitted to each communication station 17° and 178.174 at
If there is an AT, this audio data DAT is
The audio data is output from the audio data processing unit 22 and input to the line-switched LAN connection unit 15.

Then, the transmission control section 27 of the circuit-switched LAN connection section 15
In each slot of each frame Fs output from the reception control unit 24, the slave station 17. The audio data DAT to be transmitted to slave station 1 is placed in slot 2.
The audio data to be sent to slot 74 is sent to slot 10,
Audio data to be transmitted to the mask station 17 is divided into slots 9 and inserted.

On the other hand, slave station 17. Audio data D to be transmitted to each communication station 17° and 178.174 at
In the absence of AT, slot 2.9 of each frame Fs
and 10, no data symbols (NC) remain inserted.

Frame F, in which symbols have been inserted into each slot in this way, is output from the transmission control section 27 and is sent to the encoding section 2.
3 to the communication stations 173, 17, . and 17
4.

Communication station 17 explained above! The operation in each communication station 1
7. and 174 are also performed in the same way, so the explanation thereof will be omitted.

Then, master station 17. The frame F encoded and transmitted from the mask station 17. goes around the transmission path 18 and returns to the mask station 17.
When input to mask station 17. The above-described reception processing and transmission processing are also performed in , and frame F8 is encoded and transmitted again.

The operation explained above is performed by each communication station 17. By repeating steps 174 to 174, musical tone control data and audio data are communicated using one transmission path 18.

By the way, Mask Bureau 17. If there is an abnormality in a certain slot of frame F8 recovered at mask station 17. Then, a data error symbol (ER) shown in FIG. 9 is inserted into that slot and the frame is transmitted.

In addition, each communication station 17. A transmission bar corresponding to a certain slot of frame F transmitted in ~174.

If the F is overflowed, each communication station 17I~
At 174, the -rt-barflow symbol (OV) shown in FIG. 9 is inserted into that slot and frame F5 is transmitted.

Next, when the above-mentioned communication is being performed, for example, the first
Communication station 17 in the figure. A failure recovery operation when a communication failure occurs such that the transmission line 18 connecting the communication station 174 and the communication station 174 is disconnected for some reason will be explained.

In order to manage each communication station in a ring-shaped packet-switched LAN, the applicant has developed a communication station management system in which each communication station knows the address of its upstream adjacent communication station (hereinafter referred to as upstream adjacent station address). We previously jointly proposed a method (see the specification and drawings attached to Japanese Patent Application No. 1-342293).

Here, this communication station management method will be explained.

First, a masked station (hereinafter referred to as an active monitor) periodically sends a special frame (hereinafter referred to as an A
MP frames) are transmitted.

On the other hand, each downstream communication station (hereinafter referred to as a stunno (immonitor)) imports the address in the received AMP frame into its own station, and transmits an AMP frame with that address replaced with its own address to the next station. .

And the active monitor shows A who has gone around the ring.
Collects the MP frame and imports the address in the AMP frame into its own station.

According to the method described above, each communication station can always know the address of an upstream adjacent station.

By the way, if a certain standby monitor cannot receive the above-mentioned AMP frame within a certain period of time, the standby monitor detects that the active monitor is not operating normally.

In this case, the standby monitor that has detected an abnormality in the active monitor forcibly transmits a special frame (hereinafter referred to as a claim token frame) that is issued when the active monitor cannot be detected.

As a result, the active monitor that received the claim token frame ceases to be an active monitor. When all communication stations including this active monitor receive the claim token frame, they participate in the competition for selecting a new active monitor.

Next, the new active monitor selected through the above-described competition restores the ring by burning the ring. This /<-ji processing involves detecting abnormal tokens or frames that have been transmitted on the active monitor ring for one or more rounds, removing them, and generating and transmitting new tokens. Then, other communication stations synchronize with this process to initialize the ring.

The processing in the standby monitor described above is called claim token processing.

In addition, if the active monitor detects an abnormality, for example, if it detects an abnormal token or frame as described above, or if it does not detect a normal token or frame within a certain period of time, it performs the purge process described above. , restore the ring.

However, if the ring is not restored by the purge process, the process proceeds directly to the claim token process.

Furthermore, if the ring is not restored by claim token processing, the process shifts to beacon processing.

In this beacon processing, first, a communication station that has detected an abnormality generates and transmits a frame (hereinafter referred to as a beacon frame) for notifying the location of the abnormality and its cause. The communication station that has received the normal beacon frame exits the beacon process, and only the communication station that has detected an abnormality between itself and the upstream adjacent station remains. This makes it possible to identify the location of the abnormality and control the separation of the communication station with the abnormality from the ring. Then, the ring may be restored when the abnormal communication station leaves the ring automatically or according to instructions from the user of the communication station.

Incidentally, since the abnormality detection period by the five active monitors is usually shorter than the abnormality detection period by the standby monitor, the active monitor detects the abnormality first.

Therefore, the above-described concept of recovery from a communication failure is also adopted in a LAN in which stream data and commands can be communicated through one transmission path.

Normally, when normal communication is being performed, the slave station simply repeats frame F5 transmitted from the mask station or the upstream adjacent station, and performs reception processing and transmission processing at that time. Further, the clock CKT output from the packet-switched LAN connection section 4 of the slave station is the bit clock CK extracted by the PLL circuit section in the decoding section 3 of the circuit-switched LAN connection section 15.

However, when the slave station detects the abnormality using the method described above, the transmission control unit 27 detects the transmitted frame F.
Instead of repeating s, a unique frame is generated and this frame is forcibly transmitted in synchronization with a crystal oscillated clock inside the packet-switched LAN connection section 4. At this time, this frame includes packet-switched LA.
Only the symbol obtained by encoding the frame/token bit sequence F/TBA output from the N connection unit 4 is inserted into the corresponding slot. After this, the failure recovery is performed by the above-mentioned failure recovery function of the packet-switched LAN connection unit 4.
Rebuild the network.

As explained above, by using the failure recovery function of a packet-switched LAN, frames can be transmitted even if there is a failure in the LAN, so there is no need to consider communication stoppage. Further, the circuit-switched LAN connection section 15 without a failure recovery function can be used as is.

In addition, maintenance of the entire LAN is performed using a packet-switched LA.
This is performed using the frame FB6 input/output to the N connection section 4.

Furthermore, in the above explanation, each slot of the frame input/output to the circuit-switched LAN connection section 15 has been set in advance. This can be done using the output frame FBA. By doing this, each communication station 17. In steps 174 to 174, it is possible to appropriately deal with changing communication requests.

(2) Explanation of the second way of thinking A self-synchronized signal in which a clock is superimposed on data is used as the signal transmitted through the transmission line, and the (0/Level) command and stream data encoding method are both In order to mix the numbers, an encoding method is used in which three bits represent one symbol. In this case, if framing data is also encoded, communication efficiency will decrease. For example, since 2 bits are required to express three states: data (O), data (1), and framing data, communication efficiency is reduced to 1/2. However, since there are not many types of data for framing, if 4-bit data is expressed in 5-bits, the reduction in communication efficiency will be 41
It can be kept to 5.

Here, an example of the encoding method described above is shown in FIG.

In this figure, + indicates that the polarity is reversed, and - indicates that the polarity is not reversed. Also, (ND) is a symbol (
(hereinafter referred to as a no-data symbol).

Next, the data will be converted into bit frames according to the format shown in FIG. 13 and transmitted. This bit frame is of undefined length and has a bit string starting synchronization symbol (BS).
It starts with , and consists of a bit string consisting of (PO), (Pl), (SO), (Sl), and (ND). A preamble (PRA) is inserted between bit frames, and the end of the bit string is detected by detecting the preamble (PRA).

Further, a bit string start synchronization symbol (BS) is periodically inserted to enable bit synchronization.

Note that since the symbol is in units of bits, the position within the bit frame does not matter as long as the order of the symbols matches the original data.

By the way, the following two processing procedures can be considered for generating and recovering bit frames.

The first processing procedure is to generate and collect bit frames between adjacent stations, but not to repeat the bit frames. In the case of this processing procedure, each communication station collects the bit frame transmitted from the upstream adjacent station, generates a new bit frame, and transmits it to the downstream adjacent station using the clock oscillating in the local station. At this time, each station captures data symbols from the received bit frame and writes data symbols to be transmitted by the station into the bit frame to be transmitted. In addition, if there is no data,
Instead of data symbol, /- data symbol (ND
).

In the second processing procedure, similar to the first concept described above, the mask station generates and collects bit frames, and the slave station repeats the bit frames and performs reception processing and transmission processing.

Further, although any protocol may be used for the circuit-switched LAN, in the following explanation, the protocol used in the first concept described above will be used.

An example of the second concept will be described below with reference to the drawings. Here, audio data is considered as stream data, and musical tone control take is considered as a command.

(1) Description of an embodiment using the first processing procedure First, it is assumed that the configuration of the ring type LAN is the same as that shown in FIG. However, there is no distinction between mask stations and slave stations, and each communication station generates and transmits a bit frame.

Next, a block diagram of the configuration of the communication station 17 is shown in FIG.

In this figure, parts corresponding to those in FIG. 2 are given the same reference numerals, and their explanations will be omitted. In Figure 3,
28 is a connector connected to the transmission line 18 arranged between the upstream adjacent station, and 29 is a decoding unit, which decodes the bit string from the signal transmitted via the transmission line 18 and the connector 28. to detect the bit string start synchronization symbol (BS), and convert bit frame F8 to the bit string start synchronization symbol (B
Output in synchronization with S).

Further, 30 is a shunt, which inputs the bit frame F6, extracts only the symbols for the packet-switched LAN, and generates and outputs a new symbol string SPR. 31 is a decoding unit which converts the input symbol string SPR into a frame/token bit string F/TBA of a packet-switched LAN.
It is decoded and output to the exchange type LAN connection section 4. Reference numeral 32 denotes an encoding unit, which encodes a frame/talk/node sequence F/T output from the bucket exchange type LAN connection unit 4.
BA is input, encoded into a symbol string SPT, and output.

Furthermore, 33 is a shunt, which inputs the bit frame FB, extracts only the symbols for the circuit-switched LAN, and generates and outputs a new symbol string 5sIl. 34 is a circuit-switched LAN connection unit which inputs the symbol string SSB and converts the symbol string SSR into the symbol string SSR according to a predetermined processing procedure.
is processed and replaced, and a new symbol string SsT is output. 35 is an audio data processing unit, which processes audio data DA output by the line-switched LAN connection unit 34.
M processing and audio data D correction processing to be transmitted to other communication stations 17 are performed.

In addition, 36 is a combiner, 37 is an encoder, and the combiner aW
36 inputs the symbol strings SPT and SST and temporarily stores them in an internal memory in bit units.

When the symbol request signal SRQ output from the encoding unit 37 is input, the symbol strings SPT and SST are taken out from the memory and output. At this time, if there are no symbol strings SPT and SST in the memory, a no data symbol (ND) is output. The encoding unit 37 inputs the symbol strings Spy and S5 output from the combiner 36, generates a bit frame FB in which a bit string start synchronization symbol (BS) is periodically inserted, and converts the bit frame Fa into a transmission signal. The data is then encoded into a file and transmitted via the connector 38 and the transmission line 18.

In such a configuration, each communication station 17. The operation of communication of audio data and musical tone control data by 174 will be explained.

Mass, communication station 17. In, bucket,) exchangeable L A
Musical tone control data such as a key-on signal is sent from the musical tone control take processing section 21 (see FIG. 3) based on the output timing of the transmission control signal TCTL outputted from the transmission data input section 9 (see FIG. 5) of the N connection section 4. DT is output and input to the transmission data input section 9 of the packet-switched LAN connection section 4.

Next, in the bucket exchange type LAN connection section 4, a frame/token bit string F is generated based on the musical tone control data DT.
/TBA is generated, this frame/token bit string F/TBA is output in synchronization with the output clock CKT of the bucket exchange type LAN connection section 4, and is outputted to the encoding section 3.
2.

Then, the frame/talk node string F/T B
6 is encoded into a symbol string SP, r by the encoding unit 32 based on the encoding method shown in FIG. 12, and then input to the confluencer 36 and temporarily stored in an internal memory in bit units.

On the other hand, the 24-bit audio data DAT is output from the audio data processing section 35 and sent to the circuit-switched LAN.
After being input to the connection unit 34 and encoded into a symbol string SST based on the encoding method shown in FIG.
6 and temporarily stored in the internal memory in bit units.

Next, in the combiner 36, when the symbol request signal SRQ output from the encoding unit 37 is inputted, the symbol string SP? and S5T are extracted and output. At this time, if there are no symbol strings SPT and SST in the memory, no data symbols (N
D) is output.

Then, the encoding unit 37 generates a frame FB in which a bit string start synchronization symbol (BS) synchronized with an internally oscillated clock is periodically inserted based on the symbol strings SPT and SST. The bit frame F is encoded into a transmitted signal and sent to connector 38.
and is transmitted via the transmission path 18.

Next, communication station 17. In the decoding unit 29 of the transmission line 18
A symbol string is decoded from the signal transmitted via the connector 28. Then, a bit string start synchronization symbol (BS) is detected from the symbol string, outputted as a bit frame FB in synchronization with the bit string start synchronization symbol (BS), and input to the shunts 30 and 33.

Then, in the shunt filter 3o, only the symbols for the bit frame FB color bucket exchange type LAN are extracted to generate a new symbol string SPR.

This symbol string 5P11 is converted into a frame/token bit string F/T of the bucket exchange type LAN in the decoding unit 31.
The data is decoded and output to the BA, and then input to the packet-switched LAN connection section 4.

Next, in the received bit analysis section 5 of the packet-switched LAN connection section 4, the frame/token bit string F/TBA is
A frame bit string FBA constituting a frame of the packet-switched LAN is extracted from the frame bit string FBA.

Next, in the reception control section 6, reception data D3 is extracted from the frame/token bit string F/TBA and inputted to the reception data output section 7. This reception data D8 is the reception control signal R output from the musical tone control data processing section 21.
Based on the CTL, the received data output section 7 outputs the received data, inputs it to the musical tone control data processing section 21, and processes it.

Here, communication station 17. When it is time to acquire a token and transmit musical tone control data, the musical tone control data processing section 21 receives a token based on the transmission control signal TCTL output from the transmission data input section 9 of the packet-switched LAN connection section 4. Musical tone control data D is output and input to the packet-switched LAN connection section 4.

Next, in the packet-switched LAN connection section 4, a frame bit string FBA is generated based on the musical tone control data DT, and then outputted in synchronization with the output clock CKT.
The signal is input to the encoding unit 32.

Also, communication station 17. When the frame or token is simply repeated, the packet-switched LAN connection section 4 outputs the repeated frame/token bit string F/TBA to the output clock C.
It is output in synchronization with K-a and input to the encoding section 32.

Then, the frame/token bit string F/TB is encoded by the encoding unit 32 into a /interval sequence SP7, and then input to the confluencer 36, where it is temporarily stored in an internal memory in units of bits.

Also, communication station 17. If it is not the timing to output the frame/token bit string F/TBA,
Output chronograph CK from packet-switched LAN connection section 4
Since the symbol T is not output, the encoder 32 does not output the symbol sequence SPT.

On the other hand, in the shunt 33, only the symbols for the circuit-switched LAN are extracted from the bit frame F8 to generate a new symbol string 5sfl, and this symbol string S5□ is input to the circuit-switched LAN connection section 34.

Then, in the circuit-switched LAN connection section 34, audio data DAR addressed to the own station is extracted from the symbol string SSS according to a predetermined processing procedure and outputted to the audio data processing section 35. The audio data processing unit 35 also includes each communication station 17. If there is audio data DAAT to be transmitted to 173. A new symbol string Ssa is generated based on the symbol string A, is input to the combiner 36, and is temporarily stored in the internal memory in bit units.

Also, communication station 17. At each communication station 17. and 17
3. Audio data DA to be sent to 174
If there is no symbol string SsT, the circuit-switched LAN connection section 34 outputs only the symbol string SsT.

Next, when the Numpol request compensation codes S and aQ outputted from the encoding section 37 are inputted to the confluencer 36, the symbol strings SPT and S5T are taken out from the memory and outputted. At this time, the memory contains the /enhor strings SPT and SS.
If there is no t, a no data symbol (ND) is output.

Then, in the encoding unit 37, a bit frame FB is generated in which a bit string start synchronization symbol (BS) synchronized with an internally oscillated clock is periodically inserted based on the symbol string S and SsT, and the bit frame FB is generated. F8 is encoded into a transmission signal and transmitted via the funector 38 and the transmission line 18.

Communication station 17 explained above. The operation in each communication station 1
7. and 174 are also performed in the same way, so the explanation thereof will be omitted.

By repeating the above-described operations at each communication station 17 to 174, communication of musical tone control data and audio data is performed using one transmission path 18.

In addition, in one embodiment mentioned above, each communication station 17 to 174
are bit frames F
For example, communication station 17.B is generated. If the frequency of the clock of the communication station 17. is the highest and the frequency of the clock of the communication station 174 is the lowest, then the frequency of the clock of the communication station 17. Data may get stuck in the input section. However, in this case, each communication station 17. By providing a data buffer in ~174, the length of each bit frame Fs may be adjusted.

(11) Description of one embodiment of the second processing procedure First, it is assumed that the configuration of the ring type LAN is the same as that shown in FIG. Therefore, communication station 17. 17. is a mask station and a communication station that periodically transmits and collects frames. 174 are slave stations that perform reception processing and transmission processing while repeating frames. Further, the configuration of the mask station 17 is the same as that in FIG. 3.

Next, FIG. 4 shows the slave station 17. A block diagram of the configuration of ~174 is shown. In this figure, parts corresponding to those in FIG. 3 are given the same reference numerals, and their explanations will be omitted. In FIG. 4, 39 is a shunt, and the bit frame F
B is input, only the symbols for the packet-switched LAN are extracted, a symbol string 5Pil is generated and output, and a no-data symbol (N
D) is inserted into a new bit frame F'8.

Further, 40 is a shunt, which inputs the bit frame F", extracts only the symbols for circuit switched LAN, generates and outputs a symbol string SSR, and replaces the extracted / symbol with a no data symbol. A new bit frame F'8 with (ND) inserted is output.

Furthermore, 41 is a confluencer which inputs the symbol sequences SPT and SST and temporarily stores them in an internal memory in units of bits. Then, the bit frame F outputted from the shunt 40 is input, and the bit frame F is output from the shunt 40.

No data symbol (ND
) is detected, the no data symbol (ND) is replaced with the symbol strings SPT and Ss7 taken out from the memory, and a new bit string SA is output. At this time, if the symbol strings SP□ and SST are not in the memory, the bit frame F
'8 is output as is as a bit string SA.

In addition, 42 is an encoding unit which inputs the bit string SA output from the confluencer 41, encodes the bit string SA into a transmission signal, and transmits it via the connector 38 and the transmission line 18.

In such a configuration, each communication station 17. The operation of communication of audio data and musical tone control data by 174 will be explained.

First, mask station 17 in FIG. , the transmission data input section 9 of the packet-switched LAN connection section 4 (see FIG. 5)
Musical tone control data DT such as a key-on signal is outputted from the musical tone control data processing section 21 based on the output timing of the transmission control signal TCTL outputted from the packet-switched L.
The data is input to the transmission data input section 9 of the AN connection section 4.

Next, in the packet-switched LAN connection section 4, a frame/token bit string F is generated based on the musical tone control data DT.
/TBA is generated, this frame/token
The seven-digit sequence F/TBA is outputted in synchronization with the output clock CKT of the packet-switched LAN connection section 4 and inputted to the encoding section 32.

Then, the frame/token bit string F/TB is encoded into a symbol string SP in the encoding section 32 based on the encoding method shown in FIG.
6 and temporarily stored in the internal memory in bit units.

On the other hand, the audio data DAT (24 vias) is output from the audio data processing unit 35 and connected to the circuit switched LAN.
After being input to the connection unit 34 and encoded into a symbol string SsA based on the encoding method shown in FIG.
and is temporarily stored in internal memory bit by bit.

Next, in the combiner 36, when the symbol request signal SRQ output from the encoding section 37 is inputted, the symbol string SP? and Ss□ are extracted and output. At this time, if there are no symbol strings SPT and SST in the memory, a no data symbol (ND) is output.

Then, the encoding unit 37 generates a bit frame Fe in which a bit string start synchronization symbol (BS) synchronized with an internally oscillated clock is periodically inserted based on the symbol sequences SPT and Ssl, and F, is encoded into a transmission signal and transmitted via the connector 38 and the transmission line 18.

Next, slave station 17. of FIG. In the decoding unit 29, a symbol string is decoded from the signal transmitted via the transmission path 18 and the connector 28, a bit string start synchronization symbol (BS) is detected from the symbol string, and the bit string start synchronization symbol (BS) is detected as a bit frame FB. (BS) and input to the shunt 39.

Then, in the shunt 39, only the symbols for the packet-switched LAN are extracted from the bit frame F, a new symbol string SPR is generated and output, and a no-data symbol (
A new bit frame F's with the inserted bit frame F's is output.

Next, the operation from when the symbol string 5PII is input to the decoding section 31 to when the symbol strings S and T output from the encoding section 32 are input to the combiner 41 and temporarily stored in the internal memory is as described above. After the symbol string SPR explained in the first processing procedure is input to the decoding section 31 until the symbol string SPT output from the encoding section 32 is input to the combiner 36 and temporarily stored in the internal memory. Since the operation is similar to that of , the explanation thereof will be omitted.

On the other hand, in molecule iW40, bit frame F.

, only the symbols for the circuit switched LAN are extracted, a new symbol string SIR is generated and output, and a no-data symbol (
A new bit frame F'°8 in which ND) is inserted is output.Next, the symbol string SSR or the circuit switched LAN connection section 34
The operation from when the symbol string SST is input to the combiner 41 to when it is temporarily stored in the internal memory is as follows. Symbol string 56T7 after being input to connection unit 34! Since the operation is the same as that from being input to the Ic combiner 36 to being temporarily stored in the internal memory, the explanation thereof will be omitted.

Next, the confluencer 41 receives the bit frame F"°8 output from the shunt 40, and when a no data symbol (ND) is detected from the bit frame FT+, the symbol string SPT and SST is extracted, and the symbol strings SPT and SST are replaced with no data symbols (ND).As a result, the symbol string SA is output from the combiner 41.At this time, the symbol strings SPT and SST are stored in the memory. If there is no symbol string S
Output as A.

When the symbol string SA is input to the encoding section 42, the symbol string SA is encoded into a transmission signal and transmitted via the connector 38 and the transmission line 18.

Communication station 17 explained above. The operation in each communication station 1
73 and 174 are performed in the same manner, so the explanation thereof will be omitted.

Then, master station 17. When the bit frame F, encoded and transmitted from y) Frame FB is encoded and transmitted.

The operation explained above is performed for each communication station 171-17. By repeating this process, musical tone control data and audio data are communicated using one transmission path 18.

Incidentally, the LAN failure recovery operation explained in the first concept described above can also be applied to the ring LAN according to the second concept.

In addition, the LAN according to the first and second processing procedures described above
In the embodiment, an example was shown in which the configuration shown in FIG. 5 was used as the packet-switched LAN connection section 4, but the present invention is not limited to this. In other words, a ring-shaped packet-switched LAN
Any type of material may be used as long as it is used in

Furthermore, LA according to the first and second processing procedures described above
In the embodiment of N, each communication station 17 has a bucket switching type L.
Although an example has been shown in which there is one each of the AN connection section 4 and the line-switched LAN connection section 34, the present invention is not limited to this, and more LAN connection sections may be connected.

In addition, in the embodiment of the LAN according to the first processing procedure described above, the length of the bit frame F5 is undefined, and the end of the bit frame F is detected by detecting the preamble (PRA). , bit frame F
, is set to a fixed length and the bit string start synchronization symbol (B S
), the end of the bit frame FB may be detected by detecting a preset number of bits. Also, even if the bit frame FB has an undefined length,
By encoding a symbol indicating the end of the bit frame FB, this symbol is detected and transmitted.

Alternatively, the end of the frame FB may be detected.

In addition, in all of the embodiments described above, the previously proposed bucket-switching LAN connection unit is used, so an example is shown in which commands and stream data are transmitted through separate LAN connection units, but the invention is not limited to this. . That is, since it is sufficient that commands and stream data can be transmitted through one LAN, commands and stream data may be transmitted through one LAN connection section.

"Effects of the Invention" As explained above, according to the present invention, stream data and commands can be communicated over one LAN with a simple configuration and full protocol without reducing communication efficiency. .

Another advantage is that a circuit-switched LAN connection unit that does not have a failure recovery function can be used.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a ring-type LAN according to an embodiment to which the first and second concepts are applied, and FIG. 2 shows the configuration of a communication station 17 according to an embodiment to which the first concept is applied. The block diagram, FIG. 3, is a block diagram showing the configuration of the communication station 17 on the actual flow side using the first processing procedure of the second concept, and FIG. 4 shows the second processing procedure of the second concept. FIG. 5 is a block diagram showing the configuration of a slave station 17 according to an embodiment of the present invention.
FIG. 6 is a block diagram showing an example of the structure of a frame and its peripheral devices, FIG. 6 is a diagram showing an example of a frame structure according to the first concept, and FIG. Figure 8 is a diagram showing an example of the configuration of the control unit. Figure 8 is a diagram showing an example of the configuration of the control unit for transmitting and receiving signals in a ring-type LAN to which the second concept is applied. A diagram showing an example of the encoding method, FIG. 10 is a diagram showing an example of the structure of a frame according to the first concept, FIG. 11 is a diagram showing an example of the structure of audio data according to the first concept, and FIG. FIG. 13 is a diagram showing an example of the data encoding method based on the second idea. FIG. 13 is a diagram showing an example of the structure of a bit frame based on the second idea. 1.28.38・・・Connector, 3,19,293
1...Decoding unit, 4...Packet switching LAN
Connection section, 13, 23, 32.37.42... Encoding section, 15.34... Circuit switched LAN connection section, 17, ~174... Communication station , 18...
・Transmission path, 21... Musical tone control data processing section, 2
2.35...Audio data processing section, 24...
... Reception control section, 27 ... Transmission control section, 30, 3
3, 39.40... shunt, 36.41...
・Merge device.

Claims (1)

[Claims] In a ring type LAN in which a plurality of communication stations are connected in a ring shape through a transmission path and data is communicated between these stations, the plurality of communication stations have a failure recovery function and a packet a packet-switched LAN connection unit that transmits data to other stations via a transmission path and receives packet data sent via the transmission path; a circuit-switched LAN connection unit that receives stream data transmitted via a transmission path, and when a failure occurs in the plurality of communication stations or the transmission path, the packet-switched LAN connection unit A ring type LAN characterized in that failure recovery is performed using the failure recovery function.