Abstract: In assessing the capability of an IP based network to support toll telephony service, objective measurements of Speech Quality are taken. A module is used with Voice over Packet equipment that allows performance of voice quality measurements in real-time without using any external test equipment. A reference signal that includes a marker and a voice test signal is sent through the network from one Voice over Packet equipment containing or connected to the module to another. The received marker is compared to the reference marker to identify the onset time of the received voice test signal. The received and reference voice test signals are processed to measure the quality of the network. This may be implemented using the processing power and memory resources present in Voice over Packet equipment giving the network administrator an enhanced test capability at each node of the network.

Abstract: A SONET network interface for interconnecting at least one high speed unit (HSU) with at least two low speed interface units (LSUs) to enable transmission of signals therebetween. The interface having: a common bus of predetermined bit width for interfacing the HSU unit with each of the LSU units to enable transmission of signals from each of the LSUs to the HSU, and reception of the signals from the HSU to each of the LSUs; a first partition bus of the predetermined bit width for interfacing the HSU to a predetermined number of the LSUs, the first partition bus being partitioned into a first bus for interfacing the HSU to a first subset of the LSUs and a second bus for interfacing the HSU to a second subset of the LSUs; and a second partition bus of the predetermined bit width for interfacing the HSU to a predetermined number of the LSU units.

Abstract: A system and method of Acoustic Echo Cancellation includes a digital filter used to estimate the echo path is split into 2 filters: one fixed infinite impulse response (IIR) filter and one adaptive finite impulse response (FIR) filter. The fixed filter models the composite frequency response of the loudspeaker, its cabinet enclosure and the direct coupling path between the loudspeaker and the microphone(s). The adaptive filter models the time varying characteristics of the indirect coupling path between the loudspeaker and microphone.

Abstract: A mechanism for 1:1, 1+1, and UPSR path-switched protection switching, particularly for optical interface units in synchronous optical network (SONET) multiplexer equipment. A working unit and a standby unit pair protect each other in the event of a failure of the working unit or the failure of the span connected to the working unit if both the working and standby units are connected to different spans. Each unit is made responsible for detecting failures of the span that it receives and is primarily responsible for detecting a fault within the unit's own hardware or software. When a unit or span failure is detected, switch control is localized to the two units (i.e. the working and standby unit) which eliminates the need for a third control unit, which reduces processing time and reduces the system hardware.

Abstract: A SONET network interface for interconnecting a high speed unit (HSU) with low speed interface units (LSUs) to enable transmission of signals therebetween. The interface including: a bus for interfacing the HSU with each of the LSU units to enable transmission of signals from each of LSUs to the HSU, and reception of the signals from the HSU to each of the LSUs; and a backplane connected to the bus and having at least two time slots for performing full time slot interchange between the at least two LSUs, wherein any of the at least two LSUs can read received data directly from one of the at least two time slots and can place its transmit data into any other of the at least two time slots for communication with another of the at least two LSUs without exchanging the received and/or transmit data with the at least one HSU.