Abstract: A loop around system and method for use in a telephone line monitors line conditions to detect the initiation of loop testing and automatically bypasses an electronic device, such as a DSL line conditioner, used in the line to prevent the electronic device from being inadvertently detected by the testing system as a line fault. The system additionally shuts down power to itself from the line so that it does not interfere with testing, while continuing to monitor the line during testing to detect conditions that characterize the termination of testing, and then automatically switches the electronic device back into the line upon the conclusion of testing. The system and method may be employed unattended at intermediate locations in the line remote from the CO or the CPE.

Abstract: A multi-stage differential amplifier and method provides a gain versus frequency warping response characteristic that equalizes a transmission line of a given length to compensate for frequency-dependent attenuation. The warping response characteristic comprises the inverse of the attenuation versus frequency characteristic of the line, and affords a substantially flat system gain response over a predetermined frequency spectrum. The individual amplifier stages employ operational amplifiers, and are designed using SPICE simulations such that the individual responses of the stages are tailored so they combine to provide the required overall warping response to compensate the line.

Abstract: Apparatus and methods for deriving power from an active POTS twisted pair of lines for powering associated auxiliary electrical devices, such as signal processing electronics, includes a power supply for providing a regulated DC voltage and current, and a current regulator for limiting the current flowing in the twisted pair to a predetermined value that does not disrupt the normal signaling and operation of the telephone circuit. Another current regulator in the power supply limits the input current from the twisted pair during power surges to another predetermined value that prevents line latching in an off hook condition. A shared power arrangement derives power from a plurality of twisted pairs and powers another plurality of auxiliary electrical devices in parallel, thereby limiting the line current of any one twisted pair to a value that avoids disrupting the normal operation of the telephone circuit.

Abstract: A loop around system and method for use in a telephone line monitors line conditions to detect the initiation of loop testing and automatically bypasses an electronic device, such as a DSL line conditioner, used in the line to prevent the electronic device from being inadvertently detected by the testing system as a line fault. The system additionally shuts down power to itself from the line so that it does not interfere with testing, while continuing to monitor the line during testing to detect conditions that characterize the termination of testing, and then automatically switches the electronic device back into the line upon the conclusion of testing. The system and method may be employed unattended at intermediate locations in the line remote from the CO or the CPE.

Abstract: A DSL line conditioner achieves high performance sufficient to simultaneously support video, voice and data signals on standard telephone twisted pair lines over substantially greater distances than are currently available. The line conditioner automatically adjusts and sets the upstream and downstream preamplifier gains and attenuations according to the actual degradation imposed upon the upstream and downstream signals by the twisted pair line in which the line conditioner is used. The line conditioner achieves high performance by optimizing the signal-to-noise ratio and signal quality of DSL signals, and has a low power budget that enables it to operate by deriving power from the twisted pair lines over which it is used.