Abstract: One or more devices of a network having asymmetric delay are configured to participate in time synchronization protocol sessions in which a client device synchronizes its local clock to a master device. In one example, a system includes an optical line terminal configured to receive a time synchronization protocol packet from a grandmaster clock and an optical network unit (ONU) configured to calculate a residence time of the time synchronization protocol packet, encode the residence time into the packet, and to forward the packet to a client device. Moreover, the system may participate in a plurality of time synchronization protocol sessions with a plurality of client devices, such that the client devices become synchronized in frequency and phase.

Abstract: One or more devices of a network having asymmetric delay are configured to participate in time synchronization protocol sessions in which a client device synchronizes its local clock to a master device. In one example, a system includes an optical line terminal configured to receive a time synchronization protocol packet from a grandmaster clock and an optical network unit (ONU) configured to calculate a residence time of the time synchronization protocol packet, encode the residence time into the packet, and to forward the packet to a client device. Moreover, the system may participate in a plurality of time synchronization protocol sessions with a plurality of client devices, such that the client devices become synchronized in frequency and phase.

Abstract: One or more devices of a network having asymmetric delay are configured to participate in time synchronization protocol sessions in which a client device synchronizes its local clock to a master device. In one example, a system includes an optical line terminal configured to receive a time synchronization protocol packet from a grandmaster clock and an optical network unit (ONU) configured to calculate a residence time of the time synchronization protocol packet, encode the residence time into the packet, and to forward the packet to a client device. Moreover, the system may participate in a plurality of time synchronization protocol sessions with a plurality of client devices, such that the client devices become synchronized in frequency and phase.

Abstract: This disclosure is directed to techniques for facilitating clock recovery in optical networks. An optical network terminal (ONT) that terminates a fiber link of an optical network includes a clock mode selection module that automatically selects a clock recovery mode based on a type of optical network to which the ONT connects and a type of service provided to one or more subscriber devices coupled to the ONT. By automatically selecting the clock recovery module, an administrator or other user need not provision this aspect of the optical network, thereby reducing administrative tasks and facilitating the provisioning of the optical network. In addition, the techniques enable selection of the most optimal clock recovery mode based on the current state of the optical network.

Abstract: This disclosure is directed to techniques for facilitating clock recovery in optical networks. An optical network terminal (ONT) that terminates a fiber link of an optical network includes a clock mode selection module that automatically selects a clock recovery mode based on a type of optical network to which the ONT connects and a type of service provided to one or more subscriber devices coupled to the ONT. By automatically selecting the clock recovery module, an administrator or other user need not provision this aspect of the optical network, thereby reducing administrative tasks and facilitating the provisioning of the optical network. In addition, the techniques enable selection of the most optimal clock recovery mode based on the current state of the optical network.

Abstract: A method of scheduling a plurality of time multiplexed cells and a plurality of asynchronous cells in a temporal frame, which consists of first and second subframes, comprises the steps of assigning the time multiplexed cells or clusters of time multiplexed cells interspersed by a first plurality of asynchronous cells to the first frame and assigning a second plurality of asynchronous cells to the second subframe.

Abstract: A method of sequencing a plurality of cells in a superframe consisting of a plurality of frames in a temporal sequence comprises the steps of assigning one of the frames as a marker frame, assigning one of the time multiplexed cells in the marker frame as a marker cell, and coding the header bytes in the marker cell with header data. Alternatively, each of the time multiplexed cells may contain the header data without designating a marker cell.

Abstract: A frequency and phase locking apparatus for a phase alignment of a plurality of temporal frames, such as synchronous optical network (SONET) frames, includes a phase locked loop 6 coupled to lock the phase of the first frame, a first frame device 8a capable of receiving the first frame and coupled to provide a synchronous frame frequency to the phase locked loop 6, subsequent frame devices 8b . . . 8n capable of receiving frames subsequent to the first frame, and a drop clock device 22 coupled to the subsequent frame devices 8b . . . 8n to set the phases of the subsequent frames in alignment with the phase of the first frame.

Abstract: A cell bus, which reduces the number of conductors required to transfer data in a telecommunications switching fabric, contains a plurality of conductors, Data[X:0], for transmitting information. A cell bus interface generates a cell bus frame that includes a plurality of words, "X" bits in length, of both data and control information that includes, in part, routing information for the data. As a result of encapsulating data and control information into and cell bus frame for transmission on the Data[X:0] conductors, the number of conductors required to transmit data is reduced. An asynchronous transfer mode (ATM) switching fabric, which includes a plurality of cell buses configured in a point to point fashion between a cell routing unit (CRU)/ATM fiber bank interface unit (AFIU) and a plurality of optical line units (OLUs), is also disclosed.

Abstract: A frequency and phase locking method for fine phase locking of a plurality of temporal frames, such as synchronous optical network (SONET) frames, includes the steps of fine phase tracking of the first frame and setting the phases of the subsequent frames in coherence with the phase of the first frame, for example, by a plurality of drop clock signals.

Abstract: A queuing apparatus for avoiding address collision in a plurality of frames received from different interfaces includes a queuing memory 2, an address collision detector 16 which generates a frame offset for a succeeding frame colliding with its preceding frame, and a frame offset device 14 coupled to the address collision detector 16 to offset the address of the succeeding frame in response to detecting the address collision. A method of queuing the frames includes the steps of detecting an address collision between the preceding and the succeeding frames and repositioning at least some of the frames to eliminate the address collision.

Abstract: A system for limiting power supply transients in a powered up backplane when a printed circuit (PC) board is plugged in. The PC board includes first connecting pins with different lengths connecting to precharge planes on the backplane where each sequentially longer pin length is connected to a precharge plane providing a sequentially lower voltage. The first connecting pins are further connected by precharge circuits to power planes on the PC board. The precharge circuits are configured to ramp current to minimize power supply transients. In one embodiment, the precharge circuits each include a transistor and RC circuit connecting each first connecting pin to a power plane on the PC board.

Abstract: A switch provides time multiplex connections between ports in a telephone system. These connections are organized according to protocols located in software programs on an Integrated Multi-Protocol Processing unit (IMP). IMP includes several processing systems for processing the several protocols received by the telephone switch. Each of these IMP's then processes the respective protocol to produce switching control information. This switching control information is then transmitted to the telephone switch on a separate communications channel. The switch then uses this process protocol information to establish and remove telephone connections, according to the particular protocol received.