Abstract: A system for causing application of sealing current to one or more local telephony loops has a current source; a switching interface for connecting the current source to the one or more telephony loop interfaces; and a machine-readable instruction accessible to the switching interface, the instruction providing intelligence to the switching interface for identifying the one or more loops to be serviced, the time period for current application to each loop serviced, and a sequence order when more than one loop is serviced.

Abstract: Subscriber line maintenance apparatus and methods are disclosed. A maintenance operation is performed on a subscriber line in a communication system by an embedded test unit. The test unit limits an effect of the maintenance operation on communication signals that are transferred on the subscriber line during the maintenance operation. In one embodiment, the communication signals are high-frequency signals, and the limiting is achieved by performing the maintenance operation through a low-pass filter, such as the low pass filter of a Plain Old Telephone Service (POTS) splitter. The test unit may be implemented as a daughter card carried by another electronic circuit card in a Digital Subscriber Line Access Multiplexer (DSLAM), for example, so that the test unit does not occupy its own card slot in an equipment shelf. One, or more than one, test unit may be provided to serve multiple equipment shelves in a distributed communication equipment architecture.

Abstract: Distributed communication equipment architectures and techniques are disclosed. A host system includes an expansion unit through which control information and communication traffic may be exchanged with an expansion system. The expansion system is thereby controllable by a controller at the host system, significantly simplifying the design and reducing the cost of the expansion system. The expansion unit for a host system may also provide one or more configurable communication link interfaces. Each configurable interface may be independently configured as a network-side interface for connection to upstream communication equipment or as an access-side expansion interface for connection to an expansion system, allowing provisioning of network and access interfaces at the host system as needed.

Abstract: A method of establishing a transmission power level for signals transmitted in a conductor is provided in an environment where signal interference is present between the signals in the conductor and separate signals carried in a proximate conductor. The method includes the steps of determining a reference signal interference level at an end of the proximate conductor from a reference signal capable of being propagated from an opposing end of the proximate conductor and determining a transmission power level for the signals to provide a signal interference level based on the reference signal interference level. A system embodying the method is also provided.

Abstract: A method of establishing a transmission power level for signals transmitted in a conductor is provided in an environment where signal interference is present between the signals in the conductor and separate signals carried in a proximate conductor. The method includes the steps of determining a reference signal interference level at an end of the proximate conductor from a reference signal capable of being propagated from an opposing end of the proximate conductor and determining a transmission power level for the signals to provide a signal interference level based on the reference signal interference level. A system embodying the method is also provided.