Abstract: A digital information mapper and method for mapping sequences of information characters into a SONET (synchronous optical network) payload in such a manner that there can be an arbitrary mixture of control and/or data values in those sequences. Each information character comprises 9 bits consisting of an 8 bit information byte, being either a control byte or a data byte, and one octet type bit identifying the byte as control or data. A processor applies a mapping algorithm of a mapping module to the input information characters. The mapping algorithm is applied to sequences of eight input information characters, the algorithm being operable to map the information bytes of each sequence of eight information characters to eight of a sequence of nine contiguous SPE octets. The algorithm then maps the octet type bits for the eight mapped information bytes of the character sequence to the ninth octet of the contiguous SPE octets of the SPE octet sequence.

Abstract: In a method of establishing communication over a network a number of nodes are interconnected in a ring architecture. Virtual connections are set up on a pair of counter-rotating packet-based rings to interconnect the nodes. At each node packets destined for that node are extracted from the rings, outgoing packets are added to the rings, and packets on each ring not destined for that each node pass directly through. This arrangement establishes a virtual mesh structure between the nodes. Either each node transmits packets on both rings or receives packets from both rings. In the case where each node transmits packets on both rings the node selects one of the rings from which to receive packets in the absence of a fault, selects the fault-free ring from which to receive packets if only one of the rings has a fault, and selects both rings from which to receive packets if both rings have faults.

Abstract: In a method for setting up a digital synchronous cross-connect connection between data transmission units that are connected to interfaces of user devices, asynchronous interfaces are allocated an additive neutral element, and data signals that have been received in a data transmission unit via various data channels are added together. This makes it possible to accommodate even asynchronous subscribers in a synchronous cross-connect connection.

Abstract: A method of performance monitoring telecommunication signals having various formats, includes receiving a plurality of telecommunication signals comprising at least one signal having a first format and at least one signal having a second format, identifying the format of each signal received, and for each signal, proceeding with a performance monitoring activity in accordance with a set of rules associated with the identified format of each signal.

Abstract: To allow performance monitoring of the end-to-end path from the Ingress node to the Egress node of the GFP network by an FCS (Frame Check Sequence) check in a GFP (Generic Frame Procedure) frame, the FCS generation target area is set in the payload field of the GFP frame, no FCS recalculation is performed at the relay node and the GFP frame is transferred to the next node with the FCS added when the GFP frame is received even if an error is detected by the FCS check.

Abstract: An apparatus for resynchronizing data signals by using dual port data buffer storage, which prevents data corruption and subsequent system disruption from happening by employing a mechanism to keep an adequate distance between read and write address pointers. An input unit receives an incoming data stream having a cyclic data structure of N bytes. A data writing unit sequentially writes each data word of the received data stream into a storage unit with a capacity of 2N bytes in synchronization with a first clock. A data reading unit sequentially reads out each data word from the storage unit in synchronization with a second clock. A detection unit tests whether the write and read address pointers have come within a predetermined threshold distance. A relocation unit moves the read address pointer by N bytes to increase the distance between the read and write address pointers, when the detection unit has detected that the write and read address pointers have come within the threshold distance.

Abstract: A process for ring bundling reduces the number of add/drop multiplexers required for a ring deployed in a telecommunications network. The input into the process is a list of all the time slots for a ring and the offices of the ring where each of the time slots adds or drops traffic. The process groups together time slots having many add/drops in common to maximize the number of offices where all the time slots pass through without adding or dropping traffic. OC-3 time slots are initially grouped in pairs, then in fours, then in eights, and finally in groups of sixteen to form one or more OC-48 optical signals transported in the ring.

Abstract: A system and method for transparently transporting SONET virtual tributaries over a airlink are shown and described. According to a preferred embodiment of the present invention a hub is coupled to a SONET fiber optic channel which is adapted to receive and transmit SONET data packets over the fiber and to receive and transmit this information in a more efficient transport container over a wireless link to a remote subscriber system. Efficiency of bandwidth is achieved in the preferred embodiment through the use of compression of overhead bytes, dropping unnecessary path overhead information, dropping of redundant information, discarding reserved space, carrying payload in place of repetitive overhead information, and utilizing efficient error correction techniques.

Abstract: A line card for a data packet router interfaces to a high-speed standard data link, and has a first portion interfacing to the router and having a plurality of slower ports, and a second portion having a framer compatible with and coupled to the data link. The framer is coupled through an ingress and an egress data path between the framer and the slower ports, each with separate ingress buffers and egress buffers for each port. An interface control circuit controls data packet transfers between the slower ports and the framer in both directions. In a preferred embodiment a function is used by the control circuit to map packets from the link to the ports, using keys extracted from the incoming packets. For an IP packet the key is the source address, destination address (SA/DA) pair, which constrains packets for same IP conversations to be routed by the same path.

Abstract: Methods and apparatus are disclosed for providing virtual rings in SONET networks. By using an unused byte in the SONET path overhead, in conjunction with multiframe operation, restoration is performed at the sub-network connection layer or path layer to provide a finer granularity of protection which provides more efficient use of bandwidth. By restoring the operation of the SONET path overhead before exiting a virtual ring created using the present invention, the present virtual ring can be applied to the existing SONET network. Since a virtual ring provides restoration at a path level, a virtual ring can be comprised of various SONET rate interfaces. Further, restoration circuits are not dedicated, but are shared to create virtual rings as needed, which increases bandwidth efficiency and which are automatically and quickly created without the need for a centralized controller.

Abstract: Pointer action in an SDH transmission apparatus is performed in a temporally evenly dispersed manner. Timings of a received VC-4 clock and a transmit VC-4 clock, whose portions corresponding to overhead are inhibited in a clustered fashion, are evened out by a receiving-side PLL circuit and a transmitting-side PLL circuit, respectively, after which their phases are compared in a phase comparator to generate a justification request. In another aspect of the present invention, the phase comparison is made between VC-4 clocks whose clock inhibit timings are dispersed. In a further aspect of the present invention, a justification request arising from a frequency difference between the transmitting and receiving sides is combined with the justification contained in the received frame.

Abstract: An apparatus and method is described for the integrated management of Client Layer Cross-Connect functionality in an Add-Drop Multiplexer or in a Cross-Connect. The present invention provides for replacing at least one of the I/O ports present in the current apparatuses by a board having a matrix with Client Layer Cross-Connect functionality, such functionality comprising the Server Layer termination and all the functionalities connected to the Client Layer, in addition to the Client Cross-Connect functionality. The apparatus of the invention fully complies with the related ITU and ETSI Recommendations since the access to the ATM matrix is performed through SDH/SONET or PDH standard interfaces. The apparatus is easily upgradable in field.

Abstract: A unit controller for a delivery unit that interfaces telecommunications media to a switching matrix. The unit controller is partitioned into “generic” units, that can be easily configured for use as a line/trunk processor in an OC3 delivery unit. The same unit controller can be adapted for use in other types of delivery units, as well as for higher level controller applications.

Abstract: The method and system provide for transporting a secondary communication signal from a secondary carrier network with a primary communication signal from a primary carrier network. The method and system load the overhead from the secondary communication signal into unused bytes of the primary communication signal, thereby creating a transport overhead. The payload from each of the secondary communication signal and the primary communication signal are combined, thereby creating a transport payload. The transport payload is combined with the transport overhead to form a transport communication signal. The transport communication signal is sent to a destination where the transport communication signal is disassembled. The secondary communication signal's overhead and payload are removed from the transport communication signal and transmitted in a secondary communication signal to the secondary carrier network.

Abstract: A SDH test apparatus substitutes a part of payload of received SDH data with a desired data and transmits. A FIFO memory is installed between the Rx AU processor and the Tx AU processor, stores sequentially AU data extracted by the Rx AU processor and outputs to the Tx AU processor in the order of memorization. An AU pointer processor outputs an AU pointer adjusting the number of data in the FIFO memory, allowing the Tx AU processor to read in payload of AU data, after a time lag (&Dgr;T2+&Dgr;T4) of information leading head position of payload generated by the processing of AU data by the Rx AU processor and the Tx AU processor, by extracting the number of data in the FIFO memory. The Tx AU processor is composed to read out the payload of AU data from the FIFO memory, generate AU data and output to the Tx SOH processor so that the information leading position is at the position designated by the AU pointer value output from the AU pointer processor.

Abstract: A method of assigning capacity and routing flow in a bi-directional line switched SONET ring based upon ring topology and demand data defines for each pair of links of the ring a two-edge cut. Each two-edge cut divides the ring into two sets of nodes. For each two-edge cut, the capacity assignment method calculates a demand equal to the sum of all demands between nodes on opposite sides of the two-edge cut. The capacity assignment method then determines the maximum demand and sets the capacity of each link equal to one-half the maximum demand plus one-half of one demand unit. The flow routing method of the present invention calculates a cut difference for each two-edge cut. A critical cut is a two-edge cut having a cut difference equal to or less than one. If there is a critical cut with demands greater than zero on the same side of the critical cut, the method performs a first processing routine.

Abstract: Architectures for a synchronous transport network of a telecommunications system using transparent transport capabilities are presented. The telecommunications network comprises a pair of transparent multiplexers (TMuxs) connected over a bidirectional high speed span for transparently transporting high rate traffic. Each TMux consolidates traffic from a plurality (I) of linear systems or a plurality of bidirectional self-healing rings, each ring (Ki) having a ring rate Ri and at least two nodes (Ai, Bi). In another configuration, each TMux subtends a plurality of rings, such TMuxes being adapted for connection as ring nodes in a high-speed ring. The upgrades obtained with TMuxes in both the linear and ring configurations provide for per span relief for fiber exhaust where no changes to the existing systems are desired. As well, the bandwidth of an existing system may be increased on a per-span basis or the equipment count may be reduced.

Abstract: A transmission device includes a channel allocation part which groups channels defined on a transmission line into groups and allocate, for each of the groups, the channels in one of predetermined transmission modes which can be defined on a dual link formation of a network to which the transmission device can be connected.

Abstract: An improved access system for use in a Fiber-In-The-Loop (FITL) communications network is disclosed. The access system comprises a host digital terminal (HDT) and a plurality of subtending optical network units (ONUs). The digital signal processing (DSP) functions traditionally executed by line interface units (LIUs) within the ONUs are migrated to the HDT, rendering the individual ONUs simpler, cheaper and more reliable. This is made possible by the provision in each ONU of an oversampling codec for sampling (and conversion) of upstream and downstream data at a very high bit rate. The large bandwidths of the data communicated between the ONUs and the HDT are easily handled by the fiber optic medium therebetween. In the HDT, DSP functions are executed by a common pool, or bank, of DSP ASICs. Decimators are provided in the HDT in order to properly format the data for processing by the DSPs.

Abstract: A new architectural arrangement for network elements deployed in a central office (CO) is disclosed. The architectural arrangement involves dividing the network elements into an optical layer comprised of elements that have optical signal interfaces and switch optical signals, an opto-electrical layer comprised of elements that have optical signal interfaces and switch electrical signals, and an electrical layer comprised of elements that have electrical signal interfaces and switch electrical signals. The opto-electrical layer connects the optical and the electrical layer, and also connects lower-rate optical links into the CO. This layered architectural arrangement allows for more efficient use to be made of the small number of high-rate ports supported in the optical layer, and for the off loading of switching responsibility from both the optical and the electrical layers. This, in turn, improves the overall performance and capacity of the CO.

Abstract: A transport interface (10) provides add drop multiplex functionality and termination requirements for the transportation of network traffic. The transport interface (10) includes high speed units (12), broadband interfaces (16), and SONET formatters (18). Each high speed unit (12), broadband interface (16), and SONET formatter has redundant protection pairs (A and B). The high speed units (12), broadband interfaces (16), and SONET formatters (18) communicate with each other by in-band datalinks (40). The redundant protection pairs (A and B) communicate with one another by protection pair datalinks (42). The in-band datalinks (40) and the protection pair datalinks (42) provide protection switching within the transport interface (10) in the event of component failure. The in-band datalinks (40) are generated out of available or consumed bytes within either a section overhead (32) or a line overhead (34) of SONET OC-N frame (30).

Abstract: Method and apparatus for providing a communication link between support equipment in an optical network and an operation support system. In a first embodiment, dark bandwidth of the communication trunks is appropriated for use as a service channel. A master service node receives messages from the operation support system and places the messages in the dark bandwidth. Local service nodes, provided in an optical ring, monitor the dark bandwidth and route message either to support equipment at the node or to other local service nodes as appropriate. Multiplexors are provided at the master service node and local service nodes to interface between optical network elements and support equipment. A second embodiment provides a radio link between the operational support system and the service nodes of the optical network.

Abstract: A system and associated method for the synchronization and control of multiplexed payloads over a telecommunications network wherein the asynchronous timing relationships between multiplexed payloads having varied points of origin are retained subsequent to signal processing of the payloads for further transmission to a destination point. System modules 22 include a network interface section 30, a synchronization, multiplexing and control (SMC) section 50, and a processing section 110. The SMC section 50 includes network interface bus circuitry, payload segmentation and re-assembly circuitry, control and management memory and related circuitry, payload re-assembly circuitry, and processor bus interface circuitry. The processing section of module 22 provides device for data compression, echo cancellation, error correction coding, or voice and data encryption/decryption. The module 22 is dynamically configured through a software management and control interface.

Abstract: A pointer processing apparatus in an SDH transmission system used to serially conducting a pointer process on inputted multiplex data has an address generating unit for allocating an address to each channel of the multiplex data, a RAM for holding an information group obtained by a pointer extracting process and a pointer process, and RAM controlling unit for controlling a sequence of an operation to write-in/read-out the RAM to serially conduct the pointer process on the received multiplex data, thereby largely decreasing the circuit scale, the power consumption, the number of distributions and the like. A POH terminating operation process is conducted in a POH terminating operation process unit, and an obtained result of the POH terminating operation is stored in a storage area for a corresponding channel of a storage unit, whereby the POH terminating operation process can be conducted without separating a multiplex signal into channels.

Abstract: A serial optical link for transmission of payload data is utilised so as to permit transmission of information facility data unrelated to the payload data. A superframe is constructed at the transmission facility made up of a serial series of data frames. Each data frame consists of serially arranged words including a number of payload data words and a non-payload word. One non-payload word of the superframe has information facility data which provides a communication channel from the transmitting facility to the receiving facility for information unrelated to the communication of payload data. Another non-payload word has alarm and status facility data. The information facility data is stored in a FIFO buffer when received. If the FIFO buffer is within two words of being full, a full signal is incorporated in the next alarm and status facility data word which causes the receiving end to suspend sending information facility data words.

Abstract: A centrally-managed switch for interconnecting a plurality of digital signals through a plurality of selectable switch ports and controlled by a central management unit includes a cross-connect having a plurality of plesiochronous primary rate signal ports for receiving a plurality of plesiochronous primary rate signals, each plesiochronous primary rate signal comprising a plurality of channels, the cross-connect operable to switch ones of the channels of an originating plesiochronous primary rate signal to a destination plesiochronous primary rate signal.

Abstract: The present invention is a technology concerning a reception pointer processing in an SDH transmission system. The objects of the invention are to identify automatically a frame size (frame composition) of the received transmission frame in the SDH (SONET) transmission system and to perform flexibly and rapidly a reception pointer processing corresponding to the frame size.

Abstract: A wavelength-switching, mesh-based restoration method among a network of optical cross-connects (OXCs) is disclosed. The method is defined as "quasi-centralized" in that the network is first partitioned into a plurality of subnetworks, then a single "restoration controller" is defined for each separate subnetwork. The subnetwork partitioning is defined as being either "minimally overlapping", meaning that the OXCs are "clustered" in their network topology, with only a few links required to join the various, autonomous subnetworks, or "highly overlapping", meaning that the OXCs are defined as being included in more than one subnetwork. Each subnetwork restoration controller (SRC) includes a network graph and is therefore responsible for providing restoration around faults recognized in its own subnetwork.

Abstract: A method is disclosed for configuring software for acquiring PM data from telecommunication equipment in response to PM signals generated by the equipment responsive to events, including the steps of maintaining a library of product-independent, event-responsive modules, maintaining product-dependent data relating selected ones of the modules with a plurality of telecommunication equipment systems, and generating event-responsive PM software corresponding to one or more of the telecommunication equipment systems by assembling the modules in accordance with the product-dependent data.

Abstract: A multiplex type transmitting apparatus is arranged to have a plurality of slow signal receive/transmit sections for accommodating a counterpart for a SONET system or an SDH system, a multiplex separation converting section, and a receive/transmit section for a SONET system or SDH system fast signal.

Abstract: The present invention generally relates to a network and method capable confirming proper communications of high data rate optical signals between communications network devices. In particular, the present invention teaches a method of creating a "Line Trace" byte to be placed in the Line Overhead portion of the Transport Overhead of a SONET STS-1 frame optical data signal. Current Line Overhead does not incorporate any Trace functionality. With the increasing use of optical cross-connect switches within a communications network, it is essential for a network service provider to have the flexibility to move Line Terminating Equipment around via the optical switches. Thus, the present invention offers a straightforward, efficient way to achieve this necessary flexibility.

Abstract: A single-chip synchronous optical network (SONET) physical layer device includes first, second and third interface ports. An asynchronous transfer mode (ATM) interface circuit is coupled to the first interface port. A point-to-point protocol (PPP) processing circuit is coupled to the second interface port and the ATM interface circuit. A SONET framer circuit is coupled between the ATM interface circuit and the third interface port and between the PPP processing circuit and the third interface port. The device is programmable to allow multiple standard and non-standard data transmission modes, including transmitting ATM cells in SONET payloads; PPP frames in ATM cells in SONET payloads, PPP frames from a UTOPIA interface in SONET payloads and PPP frames directly in SONET payloads.

Abstract: Method and apparatus for providing a communication link between support equipment in an optical network and an operation support system. In a first embodiment, dark bandwidth of the communication trunks is appropriated for use as a service channel. A master service node receives messages from the operation support system and places the messages in the dark bandwidth. Local service nodes, provided in an optical ring, monitor the dark bandwidth and route message either to support equipment at the node or to other local service nodes as appropriate. Multiplexors are provided at the master service node and local service nodes to interface between optical network elements and support equipment. A second embodiment provides a radio link between the operational support system and the service nodes of the optical network.

Abstract: A modular approach to the mapping of data in and from a standard SDH/SONET signal is described. A module has interfaces (T0-T8) which allows to connect to it to other of its kind and thereby achieving higher data rates, i.e. access to standard signals of higher levels. By choosing among different interconnection schemes, arrangements comprising a plurality of modules are also able to support concatenated data traffic.

Abstract: A data conversion circuit is provided. The data conversion circuit includes a transceiver that can receive a first data channel in a first or second data format and convert it into a second data channel having a third data format. The transceiver can also receive data from the second data channel in the third data format and convert it into the first data channel in the first or second data format. The data conversion circuit includes a bus interface that is connected to the transceiver. The bus interface transfers data between the transceiver and a bus control module. The data conversion circuit also includes an onboard controller interface that is connected to the bus interface. The onboard controller interface transfers data between the transceiver and an onboard controller.

Abstract: The flexibility of a telecommunications switch fabric can be improved by making the fabric multipurpose. Where a switch fabric has two or more switches of different granularities, they may be connected by a terminating device in which the higher granularity circuits from the first switch are terminated and demultiplexed into the lower granularity circuits for the second switch, in addition to the lower granularity circuits from the second switch being multiplexed together to form higher granularity circuits for the first switch.

Abstract: Provided is a cross connection system for time-division multiplexed signals, upon detection of deterioration in quality, performs line setting to easily switch to a line having another directional orientation.

Abstract: Under-utilization of payload capacity of SONET/SDH SPE/VC when transporting 100 Mbps fast ethernet is avoided by providing a fast ethernet that is exactly compatible with ISO/IEC 8802-3 (ANSI/IEEE Standard 802.3), except that it is operated at 150 Mbps rather than 100 Mbps. At 150 Mbps, the payload capacity can be filled.

Abstract: A system and method for conversion and transmission of communication signals converts and grooms communication signals in the synchronous digital hierarchy and synchronous optical network formats at low multiplexing levels. In one embodiment, the system receives tributaries from a primary receiver and multiplexes them so as to embed in a payload the tributaries and lower order path overhead as payload components. The payload is converted to a synchronous optical network format and transmitted in a communication signal. However, the payload components remain in the synchronous digital hierarchy format. A converter assembly receives the communication signal and converts and grooms the payload at a virtual tributary group level to a synchronous digital hierarchy format without changing the payload components embedded therein. The converter assembly delivers the communication signal to a receiver where the payload components can be removed from the payload and delivered to a primary receiver.

Abstract: A transport interface (10) provides add drop multiplex functionality and termination requirements for the transportation of network traffic. The transport interface (10) includes high speed units (12), broadband interfaces (16), and SONET formatters (18). Each high speed unit (12), broadband interface (16), and SONET formatter has redundant protection pairs (A and B). The high speed units (12), broadband interfaces (16), and SONET formatters (18) communicate with each other by in-band datalinks (40). The redundant protection pairs (A and B) communicate with one another by protection pair datalinks (42). The in-band datalinks (40) and the protection pair datalinks (42) provide an effective means for performing protection switching within the transport interface (10) in the event of component failure. The in-band datalinks (40) are generated out of available or consumed bytes within either a section overhead (32) or a line overhead (34) of SONET OC-N frame (30).

Abstract: A connection procedure for finding by rearrangement a path for multirate, multicast traffic through an SDH cross-connect with subnetwork connection protection. If no free path for a new payload through the SDH switching hardware is available, the switching procedure looks for a path that is adequate and blocked by the least existing payload capacity. If the hunt is successful, the procedure rearranges the existing connections to make possible a path for the new payload. The procedure does not interrupt the existing connections; thus it is a "hitless" procedure. Connections for existing payloads that must be moved to make way for the new payload are queued and the connection procedure is applied recursively, to each in turn, until the queue is empty.

Abstract: The Remote SONET/SDH Loopback (RSL) is an optical network interface device consisting of a facility interface 24, a drop side interface 26, a facility receive signal splitter 12, a drop side receive signal splitter 18, an idle signal generator 16, a command logic assembly 10, and a switching circuit assembly 22. The RSL addresses the need for a low-cost sub-section layer device by efficiently processing the SONET signal to support only loopback and idle signal generation. The RSL may be provisioned to either loopback the facility or generate an idle signal when the drop side of the termination is disconnected, turned-off, or has otherwise failed to generate a valid signal. The SONET signal may also be looped back upon itself when a user controlled loopback command code is detected within the SONET overhead. The RSL otherwise passes the SONET signal unaltered. The RSL may be provisioned by the user to specify the location and characteristics of the embedded loopback command codes.

Abstract: An enhanced ATM switch with CPU node interconnect functionality and peripheral interconnect functionality and network functionality. The ATM switch provides low latency transfer between computer nodes and performs input/output operations with peripherals through the ATM network. SCSI Fibre Channel protocol (FCP) commands are implemented according to ATM standards to provide communication with peripherals. A segmentation and reassembly (SAR) unit is provided for performing ATM segmentation and reassembly. The SAR includes functional units which allow direct connection of an application agent to the core of the switch once the cell characteristics are determined by the application agent and provides ATM cell translation to and from available kernel buffers. The transmission media in the ATM network comprises digital optical links. The enhanced ATM switch may also include a synchronous optical network (SONET) interface for providing SONET transmission over the digital optical links in the ATM network.

Abstract: This device for transferring information between two digital signals includes means (26, 44; 62, 86) of selecting characteristics of a digital input signal, means (28, 46; 78, 94) of direct transmission to a digital output signal and means (28, 46; 80; 114) for the positioning within the latter, of elements of the input signal conveying first characteristics authorized, by the means of selection, to be transferred directly to the output signal, means (30, 32, 48, 50; 72, 74, 90, 92, 98) of measuring second characteristics of the input signal which are identified by the selection means, and means (78, 80, 102, 110) of modifying the output signal on the basis of the measurement values of the second characteristics so that the said second characteristics of the output signal and the input signal are identical.

Abstract: A data transmission system is used for the transmission of a large number of telephone channels between nodes in a transmission network built as a Synchronous Digital Hierarchy (SDH), where a pulse frame (e.g. STM-1) contains a large number of bytes, each of which can be used for the transmission of a telephone channel or of overhead signals for the administration of the system, and where signals from a Plesiochronous Digital Hierarchy (PDH) are introduced into the pulse frame of the Synchronous Digital Hierarchy, so that the signals from the Plesiochronous Digital Hierarchy when introduced do not occupy all the bytes in said pulse frame. At least some of the bytes of the pulse frame which are not occupied by introduction, are used for the transmission of user-specified data signals.

Abstract: A synchronous digital hierarchy digital cross-connection apparatus. The apparatus includes a synchronous signal connecting unit having a STM-N signal receiving part, a reversely multiplexing part and a STM-N signal transmitting part; an AU frame phase arranging and signal supervising unit; and an AU switching unit. The AU frame phase arranging and signal supervising unit includes a downward signal inputting part, and AU frame aligner, a signal path supervisor, a downward signal outputting part, and upward signal inputting part, an unconnected signal supervising and generating part, a selector, an upward signal outputting part and a CPU interface.

Abstract: An internal signal within a SONET element has a transport format having overhead and payload mapped in a manner similar to the Synchronous Optical Network standard mapping, except having selected overhead bytes defined differently, including a byte used for communicating odd parity calculated over an odd number of bytes of a frame of the transport format to determine correct or incorrect parity, selected bytes used for inter-module automatic protection switching, and a pointer having a selected fixed value, along with an adjusted virtual tributary pointer in a virtual tributary mode.

Abstract: A fiber optic network comprises an optical fiber connection (one fiber or two) from a central office to an intelligent interface device in the subscriber's premises. The central office includes a serving node transceiver providing communication links to/from at least a narrowband switch and a broadband switch for providing narrowband and broadband service routing. The network includes at least one passive power splitter/combiner for passing all wavelengths on the optical fiber connection between the serving node transceiver and the intelligent interface devices. All wavelengths are provided to each customer and bandwidth on the optical fiber loop is dynamically allocated for individual services on demand through two-way wavelength division multiplexing and demultiplexing as well as any necessary signal format conversions. The network has media access control functionality and utilizes a dynamic media access control procedure for allocation of the bandwidth.

Abstract: There is provided a different system transfer method for a ring transmission system and a transmission apparatus for transferring the ring transmission system constructed in the UPSR system to the BLSR system while a line is in service. A control board of the UPSR system is replaced by a control board of the BLSR system. By changing over a path switch, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a first multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system. Also, by changing over the path switch again, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a second multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system.

Abstract: A composite network protective/recovering device includes first to fourth input/output (I/O) modules. The first and third I/O modules are operational modules and the second and fourth I/O modules are protective modules. A first span connection group connects the first I/O operational module with the second I/O protective module. A second span connection group connects the third I/O operational module with the fourth I/O protective module to perform span switching. A first bidirectional line switching ring connects the first I/O operational module and the third I/O operational module to form a bidirectional ring which has two lines in each direction. A second bidirectional line switching ring is connected to the first to fourth I/O modules to form transmitting/receiving operational lines which include two lines in each direction and protective lines which include two lines in each direction.