Patent ID: 7046755
Filing Date: 2006-05-16
Classification: H04L,H04M,Y02D

Abstract:
1. A communication system, comprising: phone line side circuitry configured to be coupled to phone lines; powered side circuitry configured to be coupled to the phone line side circuitry through an isolation barrier comprised of a plurality of isolation elements; and a DC holding circuit within the phone line side circuitry, the DC holding circuit being switchable to operate in a plurality of DC holding circuit phases, the DC holding circuit having a first time constant in at least a first DC holding circuit phase of operation and having a second time constant in at least a second DC holding circuit phase of operation; wherein the powered side circuitry is configured to communicate a first digital differential signal to at least two of the plurality of isolation elements, the at least two isolation elements comprising at least a first isolation capacitor and a second isolation capacitor; wherein the phone line side circuitry is configured to communicate a second digital differential signal to the first isolation capacitor and the second isolation capacitor so that the first and second digital differential signals are both communicated across first and second isolation capacitors such that the first and second isolation capacitors bidirectionally transfer the first and second digital differential signals; wherein the powered side circuitry is further configured to provide a clock signal to the phone line side circuitry through at least one of the plurality of isolation elements; and wherein the powered side circuitry and the phone line side circuitry are configured so that power is capable of being provided from the powered side circuitry to the phone line side circuitry while still maintaining the isolation barrier.