Embodiments of the present disclosure provide interface conversion apparatuses, communication systems, and echo cancellation methods and apparatuses. The interface conversion apparatus includes a conversion component, a control component, an impedance matching component and a switch component; a first port of the conversion component connected to a two-wire communication system, a second port of the conversion component selectively connected to the control component or an input end of a four-wire communication system through the switch component, a third port of the conversion component connected to an output end of the four-wire communication system, a fourth port of the conversion component connected to an output end of the impedance matching component, and the impedance matching component connected to the control component.

Embodiments of the present disclosure provide interface conversion apparatuses, communication systems, and echo cancellation methods and apparatuses. The interface conversion apparatus includes a conversion component, a control component, an impedance matching component and a switch component; a first port of the conversion component connected to a two-wire communication system, a second port of the conversion component selectively connected to the control component or an input end of a four-wire communication system through the switch component, a third port of the conversion component connected to an output end of the four-wire communication system, a fourth port of the conversion component connected to an output end of the impedance matching component, and the impedance matching component connected to the control component.

Embodiments of the present disclosure provide interface conversion apparatuses, communication systems, and echo cancellation methods and apparatuses. The interface conversion apparatus includes a conversion component, a control component, an impedance matching component and a switch component; a first port of the conversion component connected to a two-wire communication system, a second port of the conversion component selectively connected to the control component or an input end of a four-wire communication system through the switch component, a third port of the conversion component connected to an output end of the four-wire communication system, a fourth port of the conversion component connected to an output end of the impedance matching component, and the impedance matching component connected to the control component.

Embodiments of the present disclosure provide interface conversion apparatuses, communication systems, and echo cancellation methods and apparatuses. The interface conversion apparatus includes a conversion component, a control component, an impedance matching component and a switch component; a first port of the conversion component connected to a two-wire communication system, a second port of the conversion component selectively connected to the control component or an input end of a four-wire communication system through the switch component, a third port of the conversion component connected to an output end of the four-wire communication system, a fourth port of the conversion component connected to an output end of the impedance matching component, and the impedance matching component connected to the control component.

A method of determining when there has been a change in the modem power state of a modem connected to a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT) on the line. This UER trace is compared to a historical (baseline) UER trace from the same line. A difference in the two traces in a higher frequency range (for example, DS3 for a VDSL line), is indicative of a possible modem power state change.

A method of determining when there has been a change in the modem power state of a modem connected to a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT) on the line. This UER trace is compared to a historical (baseline) UER trace from the same line. A difference in the two traces in a higher frequency range (for example, DS3 for a VDSL line), is indicative of a possible modem power state change.

An Ethernet device includes a link test pulse (LTP) generator circuit, a hybrid circuit, a transmit (TX) circuit, a receive (RX) circuit, and a post-processing circuit. The LTP generator circuit generates an LTP signal that is compliant with an IEEE 802.3 standard. The TX circuit transmits the LTP signal to an Ethernet cable through the hybrid circuit. The RX circuit receives an RX signal from the hybrid circuit during a period in which the LTP signal is transmitted through the hybrid circuit. The post-processing circuit performs a cable diagnosis of the Ethernet cable according to the RX signal.

An Ethernet device includes a link test pulse (LTP) generator circuit, a hybrid circuit, a transmit (TX) circuit, a receive (RX) circuit, and a post-processing circuit. The LTP generator circuit generates an LTP signal that is compliant with an IEEE 802.3 standard. The TX circuit transmits the LTP signal to an Ethernet cable through the hybrid circuit. The RX circuit receives an RX signal from the hybrid circuit during a period in which the LTP signal is transmitted through the hybrid circuit. The post-processing circuit performs a cable diagnosis of the Ethernet cable according to the RX signal.