Abstract: A method and apparatus for allowing a troubleshooter to reuse existing indicators, such as displays, LEDs, or specialized indicators, for a purpose other than the indicator's usual purpose. In response to an initial occurrence of a problem, the troubleshooter modifies the indicator's behavior to indicate a later occurrence of a fault or a set of faults, which may be the cause of the problem. Upon the later occurrence of the problem, the indicator is monitored for simultaneous notification of occurrence of the fault. After the problem is triaged, the modified indicator is returned to its original use. The notification from the indicator can be sensory, i.e., auditory, visible, or tactile. The indicator's change in behavior can occur after the fault happens once or an administrable threshold number of times, or intermittently. Alternatively, the change in behavior may become semi-permanent if the fault continues to occur for some administrable number of times.

Abstract: A variable-size jitter buffer is used to store information associated with a voice signal, facsimile signal or other received signal in a receiver of a packet-based communication system. The receiver determines an appropriate adjustment time for making an adjustment to the size of the buffer based at least in part on a result of a signal detection operation performed on the received signal. For example, in the case of a received voice signal, the determined adjustment time may be a time at which a state machine associated with a speech detector is in a “no speech” state. If the actual buffer size at the determined adjustment time is not within a designated range of a target computed at least in part based on one or more jitter measurements, the buffer size is adjusted at the determined adjustment time, e.g., by an amount representative of the difference between the actual buffer size and the target.

Abstract: A variable-size jitter buffer is used to store information associated with a voice signal, facsimile signal or other received signal in a receiver of a packet-based communication system. The receiver determines an appropriate adjustment time for making an adjustment to the size of the buffer based at least in part on a result of a signal detection operation performed on the received signal. For example, in the case of a received voice signal, the determined adjustment time may be a time at which a state machine associated with a speech detector is in a “no speech” state. If the actual buffer size at the determined adjustment time is not within a designated range of a target computed at least in part based on one or more jitter measurements, the buffer size is adjusted at the determined adjustment time, e.g., by an amount representative of the difference between the actual buffer size and the target.

Abstract: There is disclosed an asynchronous pulse catching circuit that, for each edge of the variable frequency input, regardless of duty cycle, will provide a pulse, synchronized to a high speed clock. There is also disclosed a pulse comparison circuit consisting of a state machine that provides slip detection between the variable input frequency and a reference input frequency. The circuit provides separate outputs indicating positive and negative slip.

Abstract: There is disclosed a clock circuit for a PBX system that uses phase locked loop technology to perform synchronization between two input signals. The system can switch between different reference sources without introducing error and without requiring the entire circuit to become realigned with the phase of the newly selected reference signal. This is accomplished with a phase build-out circuit that uses a phase locked loop divider to change the phase of the internal control signal to match the phase of the newly selected reference thereby eliminating timing changes on the system clock bus. The system can also be used to change between redundant clock circuits.