JPS60102044A - Multiplexer - Google Patents

Abstract

PURPOSE:To attain error correction at a multiplex transmission section and flexible transmission control by connecting a terminal device to a demodulator- modulator with the standard interface and assigning a channel to plural devices in a terminal device. CONSTITUTION:An information processing system S, terminal devices T1-TN and node stations C1, C2 form a loop alpha, which is controlled by the information processing system S. The node station C1 relays terminal devices TD1-TDM existing in a group at a remote location to the information processing system S. The node station C2 relays facsimile networks TR1-TRN utilizing a public telephone network and the information processing system S. A public digital exchange network DDX connected to the terminal device T1 has a clock, the clock of the loop alpha is synchronized with the clock and the terminal device T1 assigns a transmission channel. The information between the terminal devices T1- TN and the exchange network DDX is exchanged via the system S and the exchange of a call with the exchange network DDX is performed directly by the system S. Thus, the transmission with different speed is multiplexed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplexer for connecting an information processing system to a data transmission line utilized by a plurality of users located in a remotely located group.

雛】U1 line data transmission line is usually 200b/s, and 12'OOb/s or 2400' b/s
, etc. are sometimes used. However, if terminals that use such speeds gather on a campus and both use an information processing system located in a remote location, the telephone line can be transmitted more efficiently than if each terminal is connected via a separate line. A method is used that uses a modulator/demodulator to create more channels (3 channels). Conventionally, the time division multiplexer used in such cases prevents erroneous bits occurring in the multiplex transmission interval from affecting each channel. , due to the occurrence of false synchronization, a burst of false pips is generated on each channel.
occurs. In addition, since a method such as dividing the channel by bit symbol per modulation element 1 is used, an interface is provided for each channel, which is inconvenient for the terminal to control transmission because there is no flexibility in channel division. It has the disadvantage of being

The present invention eliminates the above-mentioned drawbacks, and allows DCE, that is, DTE to be connected to a modem by an interface based on international standards.
In other words, it is an object of the present invention to provide a multiplexer that can perform error correction and control channel setting in a multiplexed transmission section by connecting terminal equipment and allocating channels to multiple devices within the terminal equipment, and that can perform flexible transmission control. purpose.

There are many types to which the present invention can be applied, and a system in which many of these types are installed is shown in FIG.

Figure 1 shows an information processing system S as Tl,...,Tx
.

..., TN, TRI, ..., TRN, and TDI
,...

TDM is a communication system that is shared by various terminals. Communication lines usually take the form of point-to-point bidirectional transmissions, but this is a special case of multipoint loop lines.

In FIG. 1, this loop-shaped time-division transmission system is included, and furthermore, there are point 1-, 2-, and point lines connected radially to this loop-shaped time division transmission system.

The code format flowing through the time division system consists of repeated transmission frames of a fixed length. α shown in FIG. 1 represents the above-mentioned transmission link, which is in the form of a loop. Each node station on the loop has one transmission frame type. Fields consisting of information symbols of a transmission frame are subfields that fill a plurality of time slots 1 to 1. In Figure 1, T1
．． ..., T1°..., TN is a terminal device, and S is an information processing system. C1 is a terminal TDI located at a different location.

. . . is a node station that relays TDM to the information processing system S, TDl, . It takes the form of a two-way communication line.

DDX is a public digital switching network and has a tarot clock, and the α loop clock is synchronized with the DDX clock.
Terminal゛l,..., Ti,..., TN and D DX
Information exchange with the DDX is performed via the information system S, and call exchange with the DDX is directly performed by the information system S. T R1
,..., TRN is a facsimile network that uses the public switched telephone network. A terminal consisting of a telephone and facsimile device that can communicate with XN.

C2 provides an interface between these public telephone facsimile networks and the α loop, and communicates with the telephone facsimile network via the information system S, as in the case of communication with DDX. It is expected that the public DDX network and the public telephone fax network will share a clock source.

Terminal Ti in FIG. 1 is a general terminal station, and its transmission processing function is shown in FIG. In the figure, R is a receiving section of a line terminator that receives signals from an upper station.

CL is a master clock source, and the fundamental frequency can be automatically adjusted by voltage control. TI is a sampled data processing system that detects a signal approximately proportional to the timing shift of the received bit clock from the scramped baseband signal received at R. The sampling clock is a 1 to 1 clock, and the output is a voltage that controls the phase of the received bit clock in the direction in which the timing information becomes 0, and is applied to the oscillation frequency control terminal of C, which is the master clock source. PR is operated by the pit clock output from CL, and its input is the output of R descrampled by DS, and the
It is checked whether the code word conforms to the algebraic law of encoding by , and the result is stored in ■. Figure 2 PR
The output of the frame buffer, which is input/output from O, is inputted to the SR located next to the PR with the code Kt1 whose error is corrected according to the above-mentioned test result. SR consists of a register for recording the above-mentioned corrected code word and a clock circuit (■) for controlling its contents. This clock circuit operates by receiving the clock of CL at (■) and complies with the algebraic encoding law described above. When it is found that the frame phase detection circuit @ of the PR is reset, the transmission frame is synchronized. Figure 2 SR is the transmission system α and the terminal equipment, D
Buffering is performed between the adapter C1 for the DDX remote terminal in Figure 3, which is a DX network adapter, and C2 in Figure 1, which is an adapter for the public telephone facsimile network, and the output is sent to the lower station in Figure 2. It forms the information symbol part of the transmission frame transmitted from the terminal. PR to S
The portion of the information symbol input to R that is to be received at this node point is specified by the TI through a control channel formed by jointly using the clock circuit and some fields of the transmission frame as described below. , this part is transferred to the local terminal, the remote terminal DDX shown in FIG. 3, and the public telephone facsimile adapter C2, and at the same time these transmission codes are input and updated. The information symbol part extracted from SR through RD in this way updates the SR content through SD at the node point and transfers it to the next stage circuit called PS in FIG. Processing is performed in accordance with the law of encoding, and the result of this processing constitutes a code word, which is then scramped by the SC and output as a transmission frame to the terminal "to lower station" in FIG. 2. When creating a transmission frame, a function code is placed at the beginning, this code is detected in the PR shown in Figure 2, and the contents of the register, which generates a check result as to whether or not it is the above code word, are separated into other registers. The data is transferred to a register and the contents of the register are transferred to P' in Figure 2.
Make corrections using R. At the same time, by resetting the contents of the register, it is possible to immediately start checking whether it is a code word in 1] () of the next transmission frame, so that the transmission efficiency does not decrease.

Each link of the loop network shown in FIG. 1 transmits a code sequence forming a transmission frame created as described above, and this transmission frame is divided into a plurality of fields in the following manner.

In FIG. 2, the symbol α refers to α in FIG. 1, and each station on the α loop must have the circuit of the block diagram shown in FIG. In FIG. 1, T1 is a main station for synchronizing the operating clocks of each station, and is also a control station for allocating transmission channels. In T1, there is no wiring (■) that controls the clock source CL in FIG.
The synchronization of the operating phases in FIG. 2 is performed by a delay adjustment circuit represented by the second diagram by a plurality of signals relating to timing deviations from I. RD and SD in FIG. 2 are signal lines for transferring the contents of the SR at the timing when a transmission frame forming a code word is formed in the SR, and for updating the contents of the SR with transmission information.

The configuration of this signal line and SR is the same at each station on the α loop, but the terminal devices TI, ..., Ti, ..., TN, the information processing system S, the connection adapter DDX with DDXm, and the remote terminal The method of use differs depending on the adapter C1 for connecting to the telephone facsimile network and the adapter c2 for connecting to the telephone facsimile network. First, at the time when a code word is formed in the SR, the field structure of a transmission frame consists of a control field for configuring a control channel and an information field for configuring a plurality of communication channels for the purpose of transmitting information. Information processing system S
are terminals such as Tl, ..., Ti, ..., TN, D
The information system S, which is shared by the DX network, remote terminals, and telephone facsimile network, occupies each of the communication channels mentioned above and multi-processes tasks created by multiple users who use these communication channels. .

The terminal or line adapter connected to the information channel occupied by the information processing system S is Tl.

..., T1. ..., a terminal called TN, an adapter DDX for connecting to a DDX network, an adapter CI for six-way terminals, and an adapter c2 for connecting to a telephone facsimile network. The number of terminals or line adapters will be greater than the number of information channels.

The information channel is created by subfields or slots created by dividing the information bit fields of the signal lines RD and SD in Figure 4. These signal lines are routed to each terminal or line adapter to transmit information. Terminals or line adapters that wish to connect to the system are connected to RD and SD according to instructions from T and 1.
Select a subfield. The usage of the fields of the signal lines RD and SD is the same at each node station on α, except for the subfield for the control channel. The subfield for the control channel is used in the same way except that T1 uses it to specify various types of other node stations. T1 transmits a start code at regular intervals from the SD control channel field and examines various signals from each station returned from the RD control channel. Star 1 to code intervals are divided according to the number of stations on α, and each division corresponds to each station on α. These stations count their own divisions after detecting the start code.

When it is necessary to communicate with the information system S, a calling E number is recorded in the control channel subfield of the SD signal line.

On the other hand, at T1, the presence or absence of a code for carrying out a calling signal sent to the control channel subfield of the RD signal line of the own station is detected by finding division corresponding to each node station by detecting the start code. Thereafter, Tl selects an available information channel.

As a result, the TI consists of a code in the control channel field of the SD signal line that indicates the number of the information channel when counting the number of divisions of that station from the star 1 code transmission, or a code that indicates that the information channel is not vacant. Record the code that carries out the connection signal.

When each node sends a calling signal, it checks whether there is a connection code in front of it, waits for the calling signal, and communicates with S through the information channel designated by the code. If the connection code is dropped and fL, a calling signal is issued. If the connection code for the call signal indicates busy, a waiting process is performed.

The above control function using control channels in the control station Tl and other node stations is performed by the following unit configuration. FIG. 6 shows the general configuration of these units 1-, and the S and R terminals in FIG. 6 are connected to the terminal device and terminal operation circuit information processing unit, as well as the DDX and public facsimile adapter. , RD and SD are connected to the transmission unit, namely RD and SD of FIG. 2, respectively.

PU is a processing unit, and TP is its operating clock obtained from the main clock circuit CL in FIG.

TR is a real-time clock that interrupts PU processing for each transmission frame. There is only one PU program, and the final instruction of the program has the next interrupt. It is set to run. A1 and A2 are address decoders that address input/output signal lines from the PU while the PU executes a program. The PU program will be different for Tl, S, Ti, DDX, and public facsimile adapters. Figure 3 DDX
In this case, the functions shown in FIG. 6 are included in a block called DDK. Processing in the PU is performed recursively every TR clock and is performed using a state table. When communication is performed on an information channel, a communication procedure is executed according to a certain protocol between the terminal operating device and the information processing device, but some states of this communication procedure, that is, the steps until the communication link is established, are It is necessary to do this according to Figure 4. These requirements arise from the provision of a local area network as shown in FIG. 2, and are included in connection waiting, which is one of the states of the transmission control procedure. This connection waiting process will also include connection procedures in the DI)X and FAX networks.

The connection procedure at T1 in FIG. 1, which is the clock and connection control station, is performed as follows. First, to perform the connection procedure, we need to define a state diagram and a table. The PU in FIG. 4 has one program, and this program looks at one state diagram and table and performs corresponding processing. This program is executed every time there is a TR clock, and it is necessary to ensure that the processing of one TR clock provides the information required for the processing to be performed using the next r1 (clock).

Next, the connection method between the DDK, facsimile public network, and remote terminals and the α loop will be described.

In the case of a DDX network, it performs digital code transmission and has a memory within the network, and as a necessary condition for a digital network, it has a network clock and a third terminal that is a terminator of the circuit that connects the DDX network equipment and the local area network. The DCE in the figure supplies the clock to the inside of the premises, and the DCE in Figure 3
As shown in the connection between the DDX block and the DDX block, a clock line T is required in addition to transmitting/receiving code lines S and R, and the phase of the local network clock is synchronized with this clock. The input/output lines inside the DDX block are SD in Figure 4.
and RD, and a signal line for clock synchronization is connected to the C terminal in FIG. These connection lines are represented by the lines between T1 and DDX in Figure 1, and T1 has the PU in Figure 4 that performs the transmission function and focal line control in Figure 2; Connection with the DDX line will also be controlled by state diagrams and channel tables. These control modes are the control modes of the PU in Ti, and matching between these control modes and the connection control of the DDX line is performed by the DDX block in FIG. 3. As already mentioned, the DDK line is information processing system S.
connected to.

Although many procedures are required before communication between the DDX network and the information processing system is performed, the only part of the local area network is the selection, retention, and release of the information channel that the information processing system S has. The processing pattern in PU in 1.1 is the same as in Ti.

If a DDX instead of a terminal is connected to T1, it is only necessary to substitute the DDX adapter in the part that means the terminal in the PU processing.

Looking at the DDX adapter side, whether there is a connection request or a disconnection request can be distinguished depending on the state of the receiving side of the DCE shown in FIG.

In other words, the code transmission format of the DDX line is an "envelope" format, which is used as the S-R of the DCE and DDX adapter.
, T is detected by the DDX adapter in Figure 3 through interface lines other than T, detects connection request and disconnection request status, and notifies this to U as part of the signal line to SD in Figure 5. It is.

The T1 PU is not concerned with connection requests from the information processing system and only transmits the channel to the DDX adapter.The DDX adapter detects the function code from the channel signal and uses the envelope on the transmitting side of the DDX line. Acting on the envelope function within the code format will activate the DDX network function. TI's PU is not involved in any further steps, and any further steps in the DDX network are performed between the information processing system and the DDX network function, and if necessary, the DDX adapter performs functional relay using function codes. will be carried out.

The case where a remote terminal is directly connected to the α loop will be described. This becomes a system consisting of C1 and TDI to TDN shown in FIG. In this case, in C1, the PU executes the connection function within the premises, and is a somewhat modified version of the general Ti control style in the α loop. That is, first, a channel table is provided for terminals TD1 to TDM, and then terms TDI to TDH are added to the node numbers of the node table.

In general cases other than C1, the node number is the terminal number, but in the case of C1, the terminal number is used instead of the node number, and processing corresponding to the terminal is performed on the channel table in each state. Therefore, the PU in C1 is ]”
The general processing used for j is multi-processed for terminals TDI to TDM. Figure 1 ゛J Exploration〕1～
TDMI± is accommodated in the time division multiplexing equipment through an in-line cable or a dedicated telephone line. FIG. 5 shows the details of the subsystems C1 and "]" D1 to TDM in FIG.
It consists of M, RES, MPX, BUS and their surrounding blocks. On the other hand, the transmission units 1 to 01 in Fig. 1 and the private branch exchange unit are each TU in Fig. 5.
This is the case for PU. Terminals '1'' D1 to TDM each have bit and frame synchronization functions based on the same principle as in FIG. 2, and the 11-division multiplexer multiplexes the synchronization functions for each of these lines.

j to time division multiplexer? As shown in Figure 5, the BUS
Adapter circuit from IO to IN by bus circuit, P
Processing units 1 to RO and RES common memory are integrated. The PRO controls transmission of frame formats for transmission and reception for each terminal, TDI to TDM, and controls code transfer between the terminals and the PU, which is an adapter for the α loop. For this reason, a control status table is recorded in the memory called FM, and P
The RO processes these control status tables. The above control will be explained in more detail.

The RES is used for code transfer between units connected to the BUS, and its memory area is divided into partial areas corresponding to each unit, each having a partial address. Then, by addressing the partial address value, the addresses within the partial area are connected in the order in which they were recorded and are automatically accessed. The MPX allocates the right to access the RES in the form of time-shared slots to each peripheral unit of the BUS, allowing them to communicate with each other. The MPX provides one time slot for every number of code bits to line adapters numbered 1 to 1. When PRO 1 obtains a time slot, it reads the transmission code from the partial address of PRO and sends it to the line, and records the code received from the line by accessing the partial address of PRO. In the same way, run from 12 to IM, and PRO moves thrower 1 to f.
4) PR the contents of the partial address of PRO by
Record in the receive buffer memory in PRI', l in the transmit buffer memory i (Q).Record the transmission code to the prepared line in the partial address of each line.Next, write the slot as above. In parallel with the allocation and associated processing, the PRO uses the contents of the above-mentioned receive buffer memory, reads the items in the control status table of the corresponding terminal from the FM, and performs bit and frame synchronization processing. The codes to be transmitted to the terminal side and the information processing system side are recorded in the transmission buffer memory.The above processing in PRO is executed by a series of program steps, and this program The last instruction waits for an interrupt clock, and when an interrupt clock occurs while this instruction is being executed, the program returns to the first instruction and the same processing is performed again.This interrupt clock PRO
It is assumed that this occurs synchronously when the RES access right is granted from the MPX. The transmission and reception buffer memory of PR,0 could use a partial area of FM, which is the work memory of PRO.

The recording format of one item in the control status table is a transmission frame, which is transmitted on the TDi line corresponding to this item. Communication in TDi is a point,
This is a special case where there are two nodes on the loop in the loop transmission system.

The block configuration of a point-to-point line without multiplexing is shown in FIG. 6.

Psi, SRI, PRI and PSO, SRO, PRO
Each has the detailed configuration shown in Figure 2, and controls the transmission frame, but the information field of the frame is occupied by the terminals DTEI and DTEO in Figure 6, and the upstream information is sent to the DTEI, and the downstream information is The direction is the information sent to the DTEO. Check bits are configured corresponding to these information fields to form a transmission frame.

Therefore, the size of the transmission frame is considerably smaller than in the case of the α loop. Figure - GDCEl and DCEO are line termination devices, but they differ depending on whether LINE is a telephone line or a local area network. The content of one item in the control status table is the 15th item.
It is composed of memory elements in blocks PSI, SRI, and PRI in the figure.

The content of this memory element is updated by the combinational logic circuit shown in FIG. 2, which PRO has a set of which is applied to each item and recorded again at a predetermined location on the FM.

The information field is constructed by exchanging information with l) U and each line through the partial address area of RES in FIG.

Let us now discuss the case of connecting to α loop through a public facsimile network. This method is based on C2 and i in Figure 1.
This is done by XN and TRI to TRN connected to this. These terminals consist of a facsimile device and a telephone, and by dialing a special number on the facsimile, they are connected to a store-and-forward facility with a modem. It is logically connected to the storage and forwarding equipment by switching. The physical and logical conditions for the connection line between C2 and XN in FIG. 1 must be the same as for the connection line between TRI and XN. In order to make such a connection, the connection signal system must be adapted to the conventional type, and a relay circuit is required for this purpose. In order to configure this relay circuit, it is necessary to base it on the following terminal signal system. FIG. 7 shows the circuit configuration inside the 600 type telephone, and it is assumed that 02 is used instead of such a telephone. The signaling system for this telephone is as follows.

(1) Activation and disconnection: When you pick up the handset, that is, OF
When F HOOK, H5 closes and Ll, L2 are transmitted through the transmitter.
A DC circuit is created between them. Turns on immediately when you hang up the phone
When the call is HOOK, the HS signal is interrupted and the DC circuit is disconnected, resulting in a call termination signal.

(2) Receiving a paging signal In the 20N HOOK state, a paging signal of 16 Hz is sent from the exchange through the circuit shown in Figure 8, passing through the capacitor and ringing the bell. At this time, the relay RT in the relay circuit has an AC insensitive characteristic and is not affected. When OF F HOOK, H3 closes, a DC circuit is created, and relay IζT operates.

hold, stop the ringing signal and switch to the talking circuit.

(3) Two-turn dial When you turn a specific number on the dial to the finger stop, the DS shown in Figure 16 closes, shorting the transmitting and receiving devices and reducing the resistance in the cable that connects the telephone to the exchange. When you release your finger and reverse it, the DS opens and closes by the number of numbers.

FIG. 9 shows a dial pulse transmitting/receiving circuit. P is the reception relay of the Airno (Russ) located at the exchange, and in Figure 8 it is on the speech circuit side.In the telephone set, the dial is connected in parallel to the bell with 150Ω to protect the DS contact and prevent the bell from ringing due to intermittent current. are doing.

When connecting a telephone line to a local cord, a modulator is connected in place of the telephone receiver shown in FIG. Further, instead of the bell circuit, a digital signal processing circuit capable of detecting l G HZ is connected. FIG. 10 shows the connection relationship between such telephone circuits and node functions. The PU processing at the node is the same as the PtJ processing for FIG. 5, and has no direct relation to the outgoing/incoming call processing. As shown in Figure 10, Ll
, the cable with the switching center connected to the L2 terminal is terminated at a telephone circuit, and control codes for controlling this are exchanged with the information processing system. The information field of the transmission frame is divided into a plurality of subfields, and the main field is used to transfer information, while related control signals are transmitted using other subfields. Call processing is performed using these subfields, and as shown in Figure 10, the R and S lines from the PU are connected to the fields connected to the modulator and demodulator, as well as to the circuit for processing calls. Consists of connected fields. In the latter, the R subfield is connected to a detection circuit for the 16 HZ signal, and when it is detected the PU performs an information channel selection procedure. Further, the subfield of S is connected to blocks D and H. D is a music box mechanism that opens and closes the dial pulse selection contact DS, and H is a relay winding that opens and closes the H3 contact. It is assumed that the response to the dial is sent from the store-and-forward device of the public corporation network. These blocks are driven by function codes sent from the information system unit 1. The calling/receiving program is executed by the information processing system.

An important point in this invention is to construct a network by applying the transmission unit shown in FIG. 2 to various cases. The transmission unit of FIG. 2 is applied in a modified form to the point, two, and point circuits as shown in FIG. 5, and is also applied to each node of a loop circuit. The transmission unit shown in FIG.
It has a logical configuration that allows it to be connected to other circuits using standard interfaces. Therefore, in Fig. 5 using a modification of the circuit of Fig. 2), DCEO and DCE
I shall be connected to its adjacent circuits by a standard interface. The parts other than the line termination function shown in FIG. 2 that are connected through such an interface have the role of a multiplexer. The characteristics of this multiplexer become particularly clear when used as shown in FIG. That is, a configuration can be considered in which the DTEI is an information processing device and the DTEO is a terminal device including a plurality of terminal devices.

At this time, each device on the terminal points independently,
A two-point channel is connected to an information processing device. The transmission frame is divided into fields for each channel.

The multiplexer shown in FIG. 2 is connected to a DCE that terminates a point-to-point, point-to, or loop circuit. As already mentioned, it has a group of connection terminals, and furthermore, it has a group of connection terminals for connecting with various terminal devices included in the DTE as part of the DTE. There are many possible ways to use the latter, and each terminal on the loop α in Figure 1 can create many communication channels as described in connection with Figure 6. Multiple control channels can be created. In addition, the DTE device side of the multiplexer in FIG. 2 at the nodes C1 and C2 on the α loop shows that there is a method of connecting the connection terminal group to the point, two, point line again.

In the case of C1, the telephone line is used for code transmission, and in the case of C2, the telephone line is connected to a facsimile network. Also, in the case of T1 in Figure 1, it is digital DX11! that does not depend on the telephone line! It is connected to l.

According to the multiplexer of the present invention, it is possible to connect to a communication line through the Y(Q interface), improve the bit error rate in the communication line, and create a large number of communication channels with different information speeds. A flexible network configuration is possible.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a system t1 to which the present invention is applied, and FIG.
The figure shows an embodiment of the present invention, Fig. 3 shows a method of connecting to a public digital network using a standard interface, and Fig. 4 shows a control circuit for using an information processing device in a collinear system. , FIG. 5 is a detailed diagram of the portion indicated by block C1 in FIG. 1, FIG. 6 is a diagram showing an application example of the multiplexer of the present invention, and FIGS. 7 to 10 are detailed diagrams of the portion 02 in FIG. 1. It is. Applicant Ricoh Co., Ltd. - Figure 3 Hai2 (!1fl (BLl to D, S Figure 5

Claims (3)

[Claims] (1) The receive data terminal of the modulator and demodulator is connected to the receive terminal of the code transmission unit, and the transmit data terminal of the modulator and demodulator is connected to the transmit terminal of the code transmission unit, and the code transmission unit transmits the same format as the receive frame in the transmit frame. A multiplexer featuring: (2) The multiplexer according to item 1, in which the transmitted and received frames are created by adding a check code configured by applying algebraic coding rules to the information field. (3) The multiplexer according to item 1, wherein channels are formed by dividing the information field and allocating each division to a plurality of terminals, and each of these channels is logically connected to an information processing device.