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: Apparatus and methods for providing remote control and control redundancy for distributed communication equipment are disclosed. An expansion system in a distributed communication equipment architecture is controlled by a controller in a host system. Control information is exchanged between the host system controller and an expansion system in communication signals that are processed by one or more communication modules such as line termination cards in the expansion system. Communication signals are transferred to the communication module(s) through an expansion system control device, and control information is then transferred back to the control device. Control information may also be transferred from the expansion system control device to the host system through the communication module(s). This simplifies the design and lowers the cost of the control device, which does not process received signals.

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.