JPH0440132A - Ring-type lan - Google Patents

Abstract

PURPOSE:To communicate a stream data and a command through one LAN by simple configuration and protocol without lowering efficiency for communication by periodically inserting a synchronizing symbol to a symbol train to be outputted from a joining means and generating a new symbol train by inserting a symbol showing the absence of the symbol when there is no symbol train. CONSTITUTION:In a reception control part 24, the symbol is taken out after being divided and inserted into slots 5, 8 and 12 concerning the music control data of each frame Fs, and a no data symbol (NC) is inserted to the slots 5, 8 and 12. On the other hand, the taken-out symbols are connected and outputted successively as a symbol train SPR. Next, the symbol train SPR is decoded to a frame/taken bit train F/TBA by a decoding part 3, outputted synchronously with a clock CKR and inputted to a packet exchange type LAN connection part 4.

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 type L
AN 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, each audio data stream requires a dedicated line, and in the past, audio data communication cables 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.

By the way, the command transmission speed in a packet-switched LAN has conventionally been 4 to 1 OM bps, but
The transmission speed of stream data, especially video data, is approximately 1
00 Mbps is required. Furthermore, although the transmission speed of audio data is relatively low, the tolerance for transmission delay is extremely small. In this way, the stream data is
It has various properties different from 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 on a channel in a frequency band of 1-100 Hz, and stream data is transmitted using a different protocol on a channel in a frequency band of 101-200 Hz.

(2) A method of communicating stream data and commands by time division multiplexing. That is, it is a method in which circuit switching and packet switching are performed simultaneously on one transmission path according to the type of data.

(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.

``Problem to be Solved by the Invention J'' By the way, the above-mentioned conventional LAN has the following drawbacks.

In the method (1), it is necessary to prepare a modem for each frequency, which has the disadvantage of increasing the circuit scale.

Furthermore, the method (2) has the drawbacks of increased circuit scale and poor communication efficiency.

Furthermore, in the method (3), since the switching equipment uses hardware to allocate cells at high speed, there is a drawback that the circuit scale becomes large.

This invention was made in view of the above-mentioned circumstances, and utilizes two existing technologies, circuit-switched LAN and packet-switched LAN, to stream data and commands with a simple configuration and protocol without reducing communication efficiency. A ring-type LAN that allows communication between
is intended to provide.

"Means for Solving the Problems" The present invention provides 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.
In N, the plurality of communication stations decode a symbol string from the signal transmitted via the transmission path, detect a synchronization symbol for synchronizing the symbol string, and convert the symbol string into the synchronization symbol. a decoding means for synchronizing and outputting as a first symbol string; and a decoding means for inputting the first symbol string and extracting only the symbols used in a plurality of LANs each processing data according to a different protocol, respectively, and a plurality of shunting means for generating and outputting a symbol string; inputting the second symbol string and processing and replacing the second symbol string according to each predetermined protocol to generate a new symbol string; a plurality of LAN connection means for outputting a plurality of LAN connection means, a merging means for inputting a plurality of symbol strings respectively output from the plurality of LAN connection means and outputting a new symbol string by combining them; The synchronization symbol is periodically inserted into the symbol string to be transmitted, and if there is no symbol string, a symbol indicating the absence of the symbol is inserted to generate a new symbol string, and the symbol string is added to the transmission signal. It is characterized by comprising an encoding means for encoding and outputting the encoded data.

"Operation" According to the present invention, in the decoding means of a communication station, after a symbol string is decoded from a signal transmitted via a transmission path, a synchronization symbol is detected, and the first symbol string is converted into a synchronization symbol. Output synchronously.

Next, in the plurality of branching means, only symbols used for LANs of different protocols are respectively extracted from the first symbol string, and second symbol strings are respectively generated and output.

So, in each of the plurality of LAN connection means, the second
A symbol string is input, a second symbol string is processed and replaced according to each predetermined protocol, and a new symbol string is output.

Next, a plurality of symbol strings respectively output from the plurality of LAN connection means are input to the merging means, and a new symbol string is output by combining these symbol strings.

Then, in the encoding means, a new symbol string is generated in which synchronization symbols are periodically inserted into the symbol string output from the merging means. At this time, if there are no plural symbol strings, a new symbol string is generated in which a symbol indicating that there is no symbol string is inserted. The symbol string is then encoded into a transmission signal and output.

The above operations are performed one after another in each communication station.

Embodiment Before describing an embodiment of the present invention, a basic idea for solving the above-mentioned problems 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 packet-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 a signal transmitted via the transmission line and connector 1 and outputs a 1-bit width signal SPR.

Further, 3 is a decoding unit which decodes the frame/token bit string F/TBA from the signal SPR and also decodes the internal P
The LL circuit section extracts the bit clock CKR from the signal SPR and outputs it.

Furthermore, 4 is a packet-switched LAN connection section. In the packet-switched LAN connection section 4, 5 is a received bit analysis section, which analyzes the frame/token bit string P/T.
B Constantly inspects A, frame/token bit string P
/ TEA Timing signal ST1 regarding the start/end etc. of A. 1, detection and generation of ring priority P and reservation priority R, and extraction of frame bit string FBA constituting the frame. Here, the ring priority P, is the current priority of the token or frame transmitted on the transmission path, and the reservation priority R1 is the reservation priority of the communication station for data transmission according to the priority of data within the communication station. This is the priority used to perform the task.

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

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 unit IO, and outputs transmission data DT based on a data request signal DR outputted from a transmission control unit IO (to be described later).

IO is a transmission control unit that 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 D1 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 received bit analysis section 5, the ring priority P7, the reservation priority Rr, and the timing signal STM output from the received bit analysis section 5.

Reference numeral 11 denotes a transmission reservation unit, which inputs the larger of the reservation priority R1 and the data priority P output from the transmission control unit IO, and outputs a one value corresponding to the priority to the bit delay unit 8. Bit R+ of the reservation index of the frame/token bit string FZTBA being passed is set. I2 is the frame/token bit string F/ output from the bit delay unit 8.
This is a transmission selection unit that selects and outputs either one of the frame/token bit strings F/TBA output from TEA and the transmission control unit IO. Furthermore, this selection is
This is performed based on the selection signal SsE output from the transmission control unit IO.

13 is a frame/token bit string F/ which is output from the transmission selection section 12 of the packet-switched LAN connection section 4.
The encoding unit 14 that encodes the TBA is a transmitter that receives the output signal Spr of the encoding unit 13 and transmits a signal S27 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. 342295 and No. 1-343211. .

By the way, the packet switching type LAN connection section 4 mentioned above is
Since it can be configured using S t (large scale integrated circuit), this L
By using SI, commands can be easily communicated.

Therefore, in the present invention, the above-mentioned packet-switched LAN connection unit 4 is used to communicate commands, and the LAN for communicating commands and stream data is as follows:
The LAN uses a hybrid protocol of a line-switched protocol for stream data and a packet-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 shall be 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, it is assumed that the stream data is transmitted using a frame having N slots corresponding to N channels, as shown in FIG.

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 channels 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 l 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 l 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 Stream data is assembled.

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

This allows commands and stream data to 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, I is a connector, 4 is the packet-switched LAN connection section described above, 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: 0-level data of circuit-switched LAN 001: Level data of circuit-switched LAN O1O: 0-level data of packet-switched LAN O11: Packet-switched LAN
Therefore, by encoding circuit-switched LAN data and packet-switched LAN data using the same encoding method, the respective data can be superimposed and transmitted as one data. At the same time, it is 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 l. 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 concept described above, stream data and commands such as musical tone control data can be communicated over one LAN with a simple configuration and protocol without reducing communication efficiency.

(1) Explanation of the first idea The stream data encoding method is NRZ I (
Non Return to Zero Inver
ted) and 4B1, which represents 4 bits of data in 5 bits.
5B 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 (F'E) are synchronization symbols for frames, which are used to find the frame. The structure of the frame will be described later with reference to FIG. 10. Further, (NC) to (Ov) are synchronization symbols for data for each slot.

In FIG. 9, (reservation) means that the use is not currently considered, but it is 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 sync symbol (FS), followed by N slots (corresponding to N channels), and ending with a frame end sync symbol (FE). A preamble (PRA) is inserted between frames.

Furthermore, the size of one slot is l symbols, 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 (C6), a data error symbol (ER), and a non-data symbol of a transmit buffer overflow symbol (Ov). At each receiving station, if the symbols in the slots with the same number of each frame are connected together, it becomes, for example, 24-bit audio data, but since it is necessary to synchronize this data, the above-mentioned non-data symbols are (N.C.
) 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 (OV) can be used at the same level in frames and channels, improving communication efficiency. As the speed increases, the circuit configuration also becomes simpler, since 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 sample synchronization start symbol (CS) described above indicates the separation of each sample, and six data symbols (Do to 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 symbols 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 with audio data, one data symbol represents a 4-bit signal. The no data symbol (NC) may be placed anywhere in the symbol string, and this symbol adjusts the speed of the slot and the speed of the control data.

In addition, the packet-switched LAN data is used for musical tone control,
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 switching type L
For details on the format and usage of AN 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, multiple slots are
By assigning it to AN data, the delay can be kept to a minimum.

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, to 17. are communication stations that perform data communication with each other, and communication stations +7. 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. ~17. This is a transmission line such as an optical fiber cable that connects the two 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, ■ is a connector, and 19 is a frame F having the format shown in FIG.
15 is the above-mentioned circuit switching type LAN connection part, 4 is the above-mentioned packet switching type LAN connection part, 21 is a musical tone control data processing part, and the packet switching type LAN connection part 4 is Processing of musical tone control data D3 to be output and processing of musical tone control data DA to be transmitted to other communication stations 17 are performed.

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.

Further, in the circuit-switched LAN connection section 15, 24 is a reception control section, which extracts symbols from the audio data slot ° assigned to the local station of each input frame Ps and the packet-switched LAN slot,
Instead, a no-data symbol (NC) is inserted, and a symbol string is generated for each slot, and a symbol string SP,l for the packet-switched LAN and audio data DA are generated.
It is divided into R (see FIG. 11) and output. Of these, audio data DAI+ is output after waiting for a sample start synchronization symbol (C9), as shown in FIG.

3 is a decoding unit, which converts the input symbol string Sp□ into a packet-switched LAN frame/token bit string F/
It is decoded into T EA and output in synchronization with clock CKR.

13 is an encoding unit, and a packet-switched LAN connection unit 4
The frame/token bit string F/TBA output in synchronization with the clock CK□ is inputted to generate the symbol string SPT.
Encode and output. 27 is a transmission control unit, which transmits audio data DA? and the symbol string SPT outputted from the encoding unit 13, and insert these into predetermined slots of each frame Fs outputted from the reception control unit 24 and output them.

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 Slave station 17. -Slave station 173 slot 3
Nislep station 17. - Slave station 17° slot 4 Slave station 174 - Master station 171 Slot 6: Mask station 17. -Slave station 173 slot 7/mask station 171
- Slave station 174 slots 9. Slave station 17. - Master station 17° slot 10 Nislep station 17f - Slave station 17° slot ll Nislep station 173 - Master station 17° slot 13 Nislep station 173 - Slave station 1
7t slot 14/slave station 174-slave station 17
゜Slot 15 Nislepe station 17. -Slave station 17s
(2) Slot 5812 for transmitting musical tone control data 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 the packet-switched LAN
Musical tone control data such as a key-on signal is sent from the musical tone control data processing section 21 (see FIG. 1) based on the output timing of the transmission control signal TCTL outputted from the transmission data input section 9 (see FIG. 5) of the connection section 4. D7 is output and input to the transmission data input section 9 of the packet-switched LAN connection section 4.

Next, the packet-switched LAN connection section 4 converts the frame/token hit string F based on the musical tone control data DT.
/TBA is generated, this frame/token pit string F/TBA is output in synchronization with the output clock CKT of the packet-switched LAN connection section 4, and is outputted to the encoding section 13 of the circuit-switched LAN connection section 15. (second
(see figure). For details of the operation of the packet-switched LAN connection system 4, please refer to the specification and drawings attached to Japanese Patent Application No. 1-342291.

The frame/token bit string F/TB6 is then encoded into a symbol string SPT 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 Spa is divided and inserted into slots 5.8 and 12 of each frame Fs 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 processed by the transmission control section 27 so that the audio data to be transmitted to the slave station 17t is transmitted to the slave station 17s in slot l of each frame Fs. The desired audio data is in slot 6,
Audio data to be transmitted to slave station 174 is divided into slots 7 and inserted.

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

The frame Fs 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.
After being encoded into a transmission signal at 17.3, it is sent to the slave station 17. ~17. sent periodically to

Next, the decoding section 19 of the slave station 172 decodes the frame F5 from the signal transmitted via the transmission line I8 and the connector I, outputs the decoded frame F5, and inputs it to the circuit-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 l, is extracted from slots 1 to 15 of each input frame F5, and A no data symbol (NC) is inserted.

Further, the extracted horns are stored one after another in the internal memory of the reception control section 24, and then outputted as audio data DAR in synchronization with the sample synchronization symbol (C9).

In addition, in the reception control section 24, the symbols divided and inserted into slots 5.8 and 12 regarding the musical tone control data of each frame F8 are extracted, and the no data symbols (NC) are inserted into slots 58 and 12, respectively. inserted.

Further, the single extracted symbols are connected and sequentially output as a symbol string SPR.

Next, the symbol string SPR is decoded into a frame/token hit string F/TBA in the decoding unit 3, and then outputted in synchronization with the clock CKR, which is then used as a packet-switched LAN.
The connection part 4 is manually powered.

At this time, if no data symbols (NC) are inserted in slots 5.8 and 12 of each frame, that is, mask station +7. If information regarding the emperor control data has not been transmitted from the decoder 3, the clock CKR is not output from the decoder 3.

Therefore, the frame/token hit sequence 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
Frame bit strings FBA constituting 7L and -A of the packet-switched LAN are extracted from BA. Next, in the reception control unit 6, the frame/token bit string F/
Received data DR is extracted from TB and input to the received data output section 7. The received data DR is outputted from the received data output section 7 based on the received control signal RCTL outputted from the musical tone control data processing section 21, inputted to the musical tone control data processing section 2I, and processed.

Here, slave station 17. If it is time to acquire a token and send musical tone control data,
Transmission data input section 9 of packet-switched LA input connection section 4
Musical tone control data D is outputted from the musical tone control data processing section 2I based on the transmission control signal TCTL outputted from the TCTL, and is inputted to the packet-switched LAN connection section 4.

Next, in the packet-switched LAN connection section 4, a frame bit string FB^ is generated based on the musical tone control data D7, and then outputted in synchronization with the output clock CKt.
The signal is input to the circuit-switched LAN connection section 15 (see FIG. 2).

Also, slave station 17. frame, or
If the timing is such that the token is simply repeated, the packet-switched LAN connection section 4 outputs the repeated frame/token bit string F/TBA in synchronization with the output clock CKT, and the circuit-switched LAN connection section 15 outputs the repeated frame/token bit string F/TBA in synchronization with the output clock CKT. (See Figure 2).

The frame/token bit string F/TB is then encoded into a symbol string SPT in the encoding section 13 and then input to the transmission control section 27.

Next, the symbol string SPT is processed by the transmission control section 27.
It is divided and inserted into slots 5.8 and I2 of each frame F5.

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

Therefore, since the symbol string SPT is not output from the encoding unit 13, the transmission control unit 27 continues to insert no data symbols (NC) into slots 5.8 and 12 of each frame Fs. .

Also, slave station 17. At each communication station 17 and 1
7. ．． Audio data D^ to be sent to 174
If there is ↑, this audio data DA is output from the audio data processing section 22,
It is input to the AN connection section 15.

Then, the transmission control section 27 of the circuit-switched LAN connection section 15
In each slot of each frame F5 outputted from the reception control unit 24, the slave station 17. The audio data DAT to be transmitted to the slave station 174 is divided into slot 2, the audio data to be transmitted to the slave station 174 is inserted into slot 10, and the audio data to be transmitted to the mask station 17 is divided into slot 9.

On the other hand, slave station +7. Audio data D to be transmitted to each communication station +7°, 175, +74 at
A? If not, slot 2.9 of each frame F5
and 10, no data symbols (NC) remain 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 3, it is sent to the communication station 17 via the connector 1 and the transmission line 18.
4.

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, the frame F5 encoded and transmitted from the mask station 17I goes around the transmission path I8 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 the frame Fs is encoded and transmitted again.

The operation explained above is performed by each communication station 17. ~17. By repeating this process, 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 the slot and the frame is transmitted.

In addition, each communication station 17. -17. When the transmission buffer corresponding to a certain slot of the frame Ps transmitted in the communication station 17, -17. Then, an overflow symbol (Ov) shown in FIG. 9 is inserted into that slot, and the frame Ps is transmitted.

Next, when the above-mentioned communication is being performed, for example, the first
A failure recovery operation will be described when a communication failure occurs such as the transmission line 18 connecting the communication station 173 and the communication station 174 shown in the figure being disconnected for some reason.

In order to manage each communication station in a ring-shaped packet-switched LAN, the applicant has developed a communication 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 station management 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 standby monitor) 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 is not 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 purging the ring. In this purge process, the active monitor detects abnormal tokens or frames that have been transmitted on the ring for one or more rounds, removes them, and generates and transmits 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.

Note that since the period for detecting an abnormality by the active monitor is usually shorter than the period for detecting an abnormality 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, if normal communication is being performed, the slave station simply repeats the frame F8 transmitted from the mask station or the upstream adjacent station, and performs reception processing and transmission processing at that time. The clock CKT output from the packet-switched L/'N connection section 4 of the slave station is
This is the pit clock CKR extracted by the PLL circuit section in the decoding section 3 of the line-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.
8 is not repeated, 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 symbols obtained by encoding the frame/token bit string F/TB^ output from the N connection unit 4 are inserted into the corresponding slots. After this, the failure recovery is performed by the above-mentioned failure recovery function of the packet-switched LAN connection unit 4.
Rebuild your 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.

In addition, in the above explanation, an example was shown in which each slot of a frame input/output to the circuit-switched LAN connection section 15 is set in advance, but these changes can be made in the packet-switched LAN connection section 4. This can be done using the input/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 represent three states: data (0), 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, FIG. 12 shows an example of the one-coding method described above. In this figure, + indicates that the polarity is reversed, and - indicates that the polarity is not reversed. Further, (ND) is a symbol indicating that there is no data (hereinafter referred to as a no-data symbol), as in the first concept described above.

Next, the data will be converted into bit frames according to the format shown in FIG. 13 and transmitted. This hit frame has an undefined length and has a bit string starting synchronization symbol (BS).
The bit string starts with , and consists of (PO), (PI), (SO), (S+), 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 symbols are in bit units, 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.

In the first processing procedure, bit frames are generated and collected between adjacent stations, and the bit frames are not repeated. 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 takes in data symbols from the received bit frame and writes the 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 symbols, no data symbols (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 data is considered as command.

(i) 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 and starts the bit string. Detect synchronization symbol (BS),
The hit frame Fa is converted into a bit string start synchronization symbol (BS
) is output in synchronization with

Further, 30 is a shunt, which inputs the bit frame F8, extracts only the symbols for the packet-switched LAN, and generates and outputs a new symbol string S□. A decoding unit 31 decodes the input symbol string SPR into a packet-switched LAN frame/token bit string F/TBA and outputs it to the packet-switched LAN connection unit 4. 32
is an encoding unit which inputs the frame/token bit sequence F/TBA output from the packet-switched LAN connection unit 4, encodes it into a symbol sequence SPA, and outputs it.

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 SIR. 34 is a line-switched LAN connection unit which inputs the symbol string SsR, processes and replaces the symbol string SSR according to a predetermined processing procedure, and outputs a new symbol string SsT. 35 is an audio data processing unit, which outputs audio data DAl from the line-switched LAN connection unit 34;
+ processing and processing of audio data D to be transmitted to other communication stations 17.

In addition, 36 is a combiner, 37 is an encoder, and the combiner 36 is a symbol string S P? and SST are input and temporarily stored in the internal memory in bit units.

When the symbol request signal S3° output from the encoding unit 37 is input, the non-volume string SPT and the 58th column are taken out from the memory and output. At this time, if the symbol strings SPT and S8T are not present in the memory, a no data symbol (ND) is output. The encoding unit 37 inputs the symbol strings SPT and SsA 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 Pa 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. -174 The operation of communicating audio data and musical tone control data will be explained.

First, communication station 17. , a key-on signal, etc. is generated from the musical tone control data processing section 21 (see FIG. 3) based on the output timing of the transmission control signal TCTL output from the transmission data input section 9 (see FIG. 5) of the packet-switched LAN connection 14. The musical tone control data D7 is outputted 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 D.
After the frame/token bit string F/TBA is generated, the frame/token bit string F/TBA is outputted in synchronization with the output clock CRT of the packet-switched LAN connection section 4, and is sent to the encoding section 3.
2.

Then, the frame/token bit string F/TB4 is encoded into a symbol string SP by the encoding unit 32 based on the encoding method shown in FIG. Temporarily stored in memory.

On the other hand, the 24-bit audio data DA is output from the audio data processing section 35 and sent to the line-switched LAN.
After being input to the connection unit 34 and encoded into 55 symbol sequences based on the encoding method shown in FIG.
and is temporarily stored in internal memory bit by bit.

Next, when the symbol request signal SRQ outputted from the encoding section 37 is inputted to the combiner 36, the symbol strings SPA and SST are taken out from the memory and outputted. At this time, if there are no symbol strings S2A and SST in the memory, no data symbols (N
D) is output.

Then, the encoding unit 37 generates a bit frame F8 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. is encoded into a transmission signal and transmitted via connector 38 and transmission line 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 30, only symbols for the packet-switched LAN are extracted from the bit frame FB, and a new symbol string SPR is generated.

This Symbol string SPR is decoded into a frame/token hit string F/TBA of the packet-switched LAN in the decoding fullE31, outputted, and inputted 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 a 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 D3 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 t7. 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 DT 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 lower, and then outputted in synchronization with the output clock CK.
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 as the output clock C.
It is output in synchronization with K t and input to the encoding section 32 .

Then, the frame/token bit string F/TB is encoded into a symbol string SPT by the encoding unit 32, and then input to the combiner 36 and 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 clock CK from packet-switched LAN connection section 4
Since T is not output, the symbol string SPT is not output from the encoding unit 32.

On the other hand, in the shunt 33, only symbols for the circuit-switched LAN are extracted from the human frame F, a new symbol string SIR is generated, and this symbol string SSR is input to the circuit-switched LAN connection section 34. .

Then, in the line-switched LAN connection section 34, audio data DAR addressed to the own station is extracted from the symbol string SSR 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. and +73.17. If there is audio data DAT to be sent to
This audio data DAT is outputted from the audio data processing unit 35 and inputted to the line-switched LAN connection unit 34, and a new symbol string SsT is generated based on the input to this audio data D, and is inputted to the confluencer 36. ,
Temporarily stored in internal memory in bits.

Also, communication station 17. At each communication station +7. and 17
3.17. Audio data DAT to be sent to
If there is no non-hole string S8, the line-switched LAN connection section 34 does not output the non-hole string S8.

Next, when the symbol request signal SRQ output from the encoding unit 37 is inputted to the combiner 36, the symbol strings SPT and Ss7 are taken out from the memory and output. At this time, the symbol strings SPT and S5T are stored in the memory.
If there is no data symbol (ND), a no data symbol (ND) is output.

Then, the encoding unit 37 generates a bit 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. FB is encoded into the transmission signal and sent to the connector 38
and is transmitted via the transmission path 18.

The operation of the communication station 1'7t described above is similar to that of each communication station 17. and 17. This is also done in the same way, so the explanation thereof will be omitted.

The operation explained above is performed by each communication station 17. ~17. By repeating this process, communication of musical tone control data and audio data is performed using one transmission path 18.

Note that in the embodiment described above, each of the communication stations 17 to 17.
are bit frames F
For example, if the frequency of the clock of the communication station 171 is the highest and the frequency of the clock of the communication station +74 is the lowest, the frequency of the clock of the communication station 17.B is generated. 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 F5 may be adjusted.

(11) Second Processing Procedure 9 Description of Embodiment First, it is assumed that the configuration of the ring type LAN is the same as that shown in FIG. Therefore, the communication station +7. 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. Also, the master station 17. The configuration is the same as that of the third ryJ.

Next, FIG. 4 shows the slave station +7. ~17. A block diagram of the configuration 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 SPR is generated and output, and a no-data symbol (N
Output a new bit frame F″8 into which D) is inserted.

Further, 40 is a shunt, and a bit frame F.

is input, extracts only the symbols for circuit-switched LAN, generates and outputs a symbol string SSR, and creates a new bit frame F"8 in which a no data symbol (ND) is inserted in place of the extracted symbol. Output.

Further, 4I is a confluencer, which inputs symbol strings spT and SsT and temporarily stores them in an internal memory in bit units. Then, the bit frame F'8 output from the shunt 40 is input, and when a no data symbol (ND) is detected in the bit frame F'a, the no data symbol (ND) is transferred from the memory to the symbol string. Replaces SPT and SST with the retrieved symbol strings SPT and SST, and outputs a new bit string SA.At this time, if the symbol strings SPT and SSJ are not present in the memory, bit frame F゛°8 is directly used as the bit string SA. Output as .

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 +7 in Figure 3. , the transmission data input section 9 of the packet-switched LAN connection section 4 (see FIG. 5)
Musical tone control data D such as a key-on signal is transmitted from the musical tone control data processing section 21 based on the output timing of the transmission control signal TCTL outputted from the musical tone control data processing section 21.

is output and manually inputted to the transmission data input section 9 of the packet-switched LAN connection section 4.

Next, in the packet-switched A/N connection section 4,
After a frame/token bit string F/TBA is generated based on the musical tone control data DT, this frame/token bit string F/TBA is transferred to the packet-switched LAN connection section 4.
The signal is output in synchronization with the output clock CKT of the encoder CKT, and is input to the encoding unit 32.

The frame/token bit string F/TB6 is then encoded into a symbol string SPT by the encoding unit 32 based on the encoding method shown in FIG. is temporarily stored.

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.
Connection f! 134 and encoded into a symbol string s5□ based on the encoding method shown in FIG. 12, the signal is input to the combiner 36 and temporarily stored in an internal memory in bit units.

Next, when the symbol request signal Sho output from the encoding unit 37 is inputted to the combiner 36, the symbol strings SPT and SST are taken out from the memory and output. At this time, if the symbol strings SPT and SIT do not exist in the memory, a no data symbol (ND) is output.

Then, the encoding unit 37 generates a bit 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 S2□ and SsA. Frame FB is encoded into a transmission signal and transmitted via connector 38 and transmission path I8.

Next, in the decoding unit 29 of the slave station 17t in FIG. It is detected, outputted as a bit frame FB in synchronization with the bit string start synchronization symbol (BS), and inputted to the shunt 39.

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

Next, the symbol string SPR is input to the decoding section 31, and then the symbol string Sbi output from the encoding section 32 is input to the combiner 4.
The operation from inputting the symbol string SPR to the decoding unit 31 to temporarily storing it in the internal memory is from inputting the symbol string SPR to the decoding unit 31 to temporarily storing it in the internal memory.
Since the operation is the same as that from inputting the symbol string SPT outputted from the unit to the confluencer 36 and temporarily storing it in the internal memory, the explanation thereof will be omitted.

On the other hand, in the shunt 40, only the circuit-switched LAN symbols are extracted from the bit frame F8, a new symbol string 5sll is generated and output, and a no-data symbol (N D
) is inserted into the new bit frame F°°8. Next, the symbol string SSR is outputted to the circuit-switched LAN connection unit 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 the operation of the symbol string Sst explained in the first processing procedure described above.
Since the operation is the same as that from when the SR is input to the line-switched LAN connection unit 34 until the symbol string S87 is input to the confluencer 36 and temporarily stored in the internal memory, the explanation thereof will be omitted.

Next, the bit frame F°°8 outputted from the shunt filter 40 is input to the confluencer 4I, and when the bit frame F'' okara no data symbol (ND) is detected, the symbol string S PT is output from the memory. and Sst are extracted, and the symbol strings SPT and SST are replaced with no data symbols (ND).
A symbol string SA is output from the combiner 41. At this time,
If the symbol strings SPT and SST are not stored in the memory, the bit frame F°°8 is output as is as the symbol string SA.

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 17. This is also done in the same way, so the explanation thereof will be omitted.

And mask station +7. The bit frame FB encoded and transmitted from t7. to t7 goes around the transmission path 18 and returns to the mask station t7. When input to the mask station 17, the above-described reception processing and transmission processing are also performed, and the bit frame Fa is encoded and transmitted again.

The operation explained above is performed by each communication station 17. -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 shown in FIG. 5, the configuration shown in FIG. 5 is used as the packet-switched LAN connection section 4, but the present invention is not limited thereto. That is, a ring-shaped packet-switched LA
Any type of material used in N may be used.

Furthermore, LA according to the first and second processing procedures described above
In the embodiment N, each communication station 17 has a packet-switched 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 L A N embodiment according to the first processing procedure described above, the length of the bit frame F5 is undefined, and the end of the bit frame FB is detected by detecting the preamble (PRA). However, the bit frame F+s is fixed length and the bit string start synchronization symbol (B
After S), the end of bit frame F8 may be detected by detecting a preset number of bits. Furthermore, even if the bit frame FB has an undefined length, by encoding a symbol indicating the end of the bit frame FB, this symbol may be detected to detect the end of the bit frame FB.

Furthermore, in all of the embodiments described above, since the previously proposed packet-switched LAN connection unit is used, an example is shown in which commands and stream data are transmitted through separate LAN connection units, but the present 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 protocol without reducing communication efficiency. .

[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. 3 is a block diagram showing the configuration of the communication station 17 according to an embodiment using the first processing procedure of the second concept, and FIG. 4 is a block diagram showing the configuration of the communication station 17 using 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. 1θ 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, 3.19,29
゜31...Decoding section, 4...Packet switching type LAN connection section, 13, 23, 32, 37.42...
... Encoding section, 15.34 ... Line switching type L
AN connection section, 17, ~17. ...Communication Bureau, 18
...Transmission path, 21...Music tone control data processing section, 22.35...Audio data processing section, 24...Reception control section, 27... ... Transmission control section, 30, 33, 39.40 ... Shunt switch,
36.41... Merger. Figure 1

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 communication is performed between these stations, the plurality of communication stations are configured to: a decoding unit that decodes a symbol string from a signal, detects a synchronization symbol for synchronizing the symbol string, synchronizes the symbol string with the synchronization symbol, and outputs the synchronization symbol as a first symbol string; and the first symbol. a plurality of branching means for inputting a sequence and extracting only symbols used in a plurality of LANs each processing data according to a different protocol, respectively generating and outputting a second symbol sequence; and the second symbol. a plurality of LAs that input a string, process and replace the second symbol string according to respective predetermined protocols, and output a new symbol string;
N connection means; a merging means for inputting a plurality of symbol strings respectively output from the plurality of LAN connection means and outputting a new symbol string by combining them; A synchronization symbol is periodically inserted, and if there is no symbol string, a symbol indicating the absence of a symbol is inserted to generate a new symbol string, and the symbol string is encoded into a transmission signal and output. A ring type LAN characterized by comprising: encoding means.