Abstract: In a phase-locked loop, multiple input clock references can each connect to a different interface card. Each interface card can include a phase comparator portion of a phase-locked loop. The phase comparators can produce a phase error signal for a phase-locked loop. One or more of the phase error signals can be transmitted across a bus, such as a time division multiplexed bus, to a system card. The system card can include a controlled oscillator portion of the phase-locked loop. The output of the system card can then sent back to one or more of the interface cards to complete the phase-locked loop.

Abstract: A system and method for managing resources in a distributed xDSL modem pool arrangement including a first number of front-end modules and a second number of back-end modules. In a preferred embodiment, when a back-end module identifies that its associated call session has entered idle-mode, idle-mode processing is performed in a manner which reduces processing load and electrical power consumption but does not result in a loss of synchronization or require retraining. A repetitively transmitted single modulated symbol transmitted from a user terminal device coupled to the modem pool indicates idle periods in user data. In the preferred embodiment, the modulated symbol to be transmitted is selected such that its spectral properties match those of user data modulated symbols.

Abstract: Methods and apparatus implementing a technique for a virtual end office. The virtual end office includes one or more pre-switch adjuncts forming a single logical construct. Each pre-switch adjunct is connected to a local exchange switch in a telephone network and provides special services to subscribers. The pre-switch adjuncts have a common exchange prefix code and so a subscriber can access special services from anywhere in the network by using the same exchange prefix code, so long as the switch the subscriber is using is connected to a pre-switch adjunct.