Fujitsu Corporation

Nippon Telegraph and Telephone Corporation

Tomohiro Shinomiya

Kazuo Iguchi

Tetsuo Soejima

Shigeo Amemiya

Haruo Yamashita

Koji Tezuka

Hiroshi Takeo

Nagao Shimada

Hiroaki Komine

Masatake Miyabe

Toshiaki Watanabe

Jun Tanaka

Hiroyuki Sato

Junichi Tamura

Kazuyuki Tajima

Akihiro Yasuo

Masaki Hirota

Kazuo Murano

Toshio Shimoe

Misao Fukuda

Shinji Ohta

Masamichi Kasa

Ryuichi Kondo

Shigeatsu Samukawa

Nobuyuki Umeda

A method for time-division multiplexing including steps of generating a plurality of first signals and a plurality of second signals to which specific pulse trains for frame synchronization are allocated respectively; generating low speed signals of plural channels including the first and second signals and transmission signals; a conversion step; and time-division multiplexing the low speed signals after the conversion step, thereby obtaining high speed signals. When applied to SDH, for example, the first and second signals may be A1 bytes and A2 bytes respectively, and the transmission signals may ho payload signals. According to one aspect of the invention, at the conversion step, the first and second signals in each channel are panty convened into either of '1/0' alternating signals and '0/1' alternating signals. Consequently, it becomes possible to reduce the number of successive same code and to diminish the deviation of the mark rate.

Method for time-division multiplexing

Disclosed is a ring network in which a plurality of transmitting apparatuses are connected in ring form so as to be capable of transmitting in each of upstream and downstream directions, working and protection channels are assigned to each direction and, when failure occurs in a transmission path, a transmit signal is looped back using the protection channel to effect rescue. The ring network includes an insert transmitting apparatus that incorporates a packet, which enters from a lower-order side, into a higher-order signal and transmits the signal to a transmission path, and a drop transmitting apparatus that extracts the packet from the higher-order signal and transmits the packet to another lower-order side. Monitoring is performed to determine whether communication between the insert and drop transmitting apparatus has become unrescuable owing to transmission-path failure. When communication has become unrescuable, the insert transmitting apparatus halts the transmission of the packet to the transmission path.

Transmitting apparatus

There is provided a communication system directed to inhibiting degradation of the efficiency of transmission of user information and improving the communication quality. A correspondence table management unit creates a correspondence table based on table forming information. A buffer status value acquiring unit acquires a buffer status value of a buffer that issues a transmission event. A notice information setting unit compares a size relation between status information about past buffer status values for the buffer and a current buffer status value acquired, and sets notice information on a bit basis. A terminal-side notice information management memory stores and manages the notice information as the status information. A notice information sending unit sends the notice information to notify an upper device of the buffer status. A table forming information sending unit sends the table forming information. A control-side notice information management memory receives and manages the notice information. A buffer status recognizing unit recognizes the buffer status from the content of the control-side notice information management memory.

Communication system preforming control of information between a terminal device and a network side device including buffer management

A subscriber-line-terminating apparatus for dynamically allocating band portions to a plurality of terminal apparatuses includes an in-buffer-information-amount receiving unit for receiving an in-buffer-information amount from each of the terminal apparatuses; an insufficient-band-computing unit for computing an insufficient band portion required by each of the terminal apparatuses; an in-buffer-information-amount-proportional-band-allocating unit for allocating a band portion corresponding to the in-buffer-information amount to each of the terminal apparatuses and a past-use-band-allocating unit for allocating a past-use band part to each of the terminal apparatuses as a past-use band portion based on a first past-use band variable of the terminal apparatus.

Dynamic band-allocating subscriber-line-terminating apparatus

In a system where a plurality of terminal units are connected to a network unit via an optical transmission line and packets are transmitted in units of cells according to polling information, polling request information including the number of variable-length packets stored in the buffer of each of the terminal unit, the number of cells composing each variable-length packet and the number of remaining cells of a packet being read is created, polling information corresponding to a time slot allocated according to the polling request information is transmitted from the shared band control unit of the network unit, and bands are allocated to the plurality of terminal units.

Band allocation method and transmission system for transmitting variable-length packets

A cross-point type switch includes a plurality of basic elements arranged in rows and columns so as to form a matrix arrangement of the basic elements. Each of the basic elements includes a plurality of input ports, output ports, expanded input ports and expanded output ports. A write/read part is connected to a common memory and has the function of writing data into the common memory and reading out the data from the common memory. A selector part selectively outputs either the data read out from the common memory or data from the expanded input ports to the output ports. The expanded output ports are directly connected to the input ports.

Cross-point type switch using common memories

When input signals from a plurality of input ports are selected and are inserted into the time slots to be output from a single output port and to insert respective signal data into time slots in synchronization with a synchronizing signal, the apparatus is so constructed that selector units (5-i) are provided to correspond to input ports (1-i), and a synchronizing signal generating unit (4) is provided to output, synchronously, a synchronizing signal and selecting signal information for designating a selector unit (5-i); the selector unit (5-i) being provided with a determining unit (6) for determining whether or not the selecting signal information designates the selector.

Input-output signal control apparatus

A switch includes a plurality of memories respectively having write terminals connected to input ports and output terminals, each of the memories including an input acknowledgement signal generating block for generating an input acknowledgement signal when data is received thereto. A multiplexer, which is coupled between the read terminals of the memories and an output port, connects one of the memories to the output port in response to a port number signal. An output controller, which is coupled to the memories and the multiplexer, receives the input acknowledgement signal from each of the memories in order of receipt and generating the port number signal so that data stored in the memories is selected by the multiplexer in order of receipt of the input acknowledgement signal.

Switch coupled between input and output ports in communication system

A communication system containing a master station and a plurality of slave stations. The master station receives a request from one of the plurality of slave stations and memorizes one or more requests from one or more slave stations. The master station also sends a request sending allowance signal which addresses one of the plurality of slave stations to give an allowance to send a request for sending data, and sends a data sending allowance signal which addresses one of the plurality of slave stations to give an allowance to send data, according to a request which is memorized. Each of the slave stations detects a request sending allowance signal which addresses its own slave station, and a data sending allowance signal which addresses its own slave station. Each of the slave stations also sends a request for sending data to the master station when its own slave station detects a request sending allowance signal which addresses its own slave station. In addition, each slave station sends data to the master station when its own slave station detects a data sending allowance signal which addresses its own slave station.

Communication system carrying out polling for request and data

A communication system including a master station, a plurality of slave stations each for communicating with the master station, a two-way transmission line connecting the master station and the plurality of slave stations. Each of the slave stations sends a request for further communication with the master station, to the master station when its own slave station is allowed to communicate with the master station and its own slave station has the above request. The master station detects the request for further communication with the master station in a signal sent from a slave station, and memorizes the slave station from which the request for further communication with the master station is detected, until an allowance signal is sent to the slave station from the master station corresponding to the memorizing of the slave station. The master station has a cyclic address pointer which points to an address of a next one of the slave stations in a cyclic order when no slave station is memorized in the master station. The master station outputs the allowance signal to communicate with the master station to a slave station which is memorized in the master station or to a slave station the address of which is pointed to by the cyclic address pointer when no request is memorized in the master station.

Polling communication system with priority control

A coded transmission system wherein each bit of transmitted data having a logical value is coded depending on a coded result of a preceding bit. The coded transmission system contains a sender-side apparatus, a transmission line, and a receiver-side apparatus. In the sender-side apparatus, a resetting bit and a message are generated; a code of a bit last transmitted which is necessary to code a bit which is to be transmitted next is memorized in a first preceding code memorizing circuit; and the content of the first preceding code memorizing circuit is reset to an initial code responding to the resetting bit. A coding circuit receives the resetting bit and the message, codes each bit of the message in accordance with a predetermined coding rule and the content of the first preceding code memorizing circuit, and codes the resetting bit to a predetermined resetting code which is different from the codes used in the coding of the message. In the receiver-side apparatus, a code of a bit last received which is necessary to decode a code of a bit which is received next is memorized in a second preceding code memorizing circuit. A resetting circuit resets a content of a second preceding code memorizing circuit to a predetermined initial code when receiving the resetting code. A decoding circuit decodes the received codes corresponding to the message in accordance with the predetermined coding rule and the content of the second preceding code memorizing circuit.

Coded transmission system with initializing code

In a sequential polling type communication network system including a master station, a first channel, a second channel, and at least two slave stations, the master station includes request registration units for registering data transmission requests from slave stations during a data transmission by another slave station, and an interrupt polling unit for polling the slave station which has issued the data transmission request after completion of the data transmission or completion of a polling of a slave station, and the slave station includes a unit for responding to a polling during the data transmission, and transitting a data transmission request when data to be transmitted exists, and for responding to the interrupt polling from the master station, and transmitting the data to the master station until the data transmission is completed.

Polling network communication system having transmission request

Disclosed is a frame synchronizing apparatus in a receiving equipment for receiving digital signals for PCM communication. The digital signals consists serial signals at a rate of f.sub.0 (bps). The serial signals include a frame synchronizing signal consituting n bits or a part of the frame synchronizing signal, collectively arranged in one frame. To attain a high-speed operation and a shorter synchronization establishing time, the apparatus comprises a latching circuit for converting the serial signals into parallel signals and for latching the parallel signals, and a circuit for detecting a plural number of times of synchronization during the n bit interval in one frame.

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Kawasaki, Japan

Tomohiro Shinomiya