Interface conversion apparatus, communication system, and echo cancellation method and apparatus

A communication system, comprising:

• a two-wire communication system;
• a four-wire communication system;
• and
• an interface conversion apparatus, wherein the interface conversion apparatus is configured to interface with the two-wire communication system and the four-wire communication system, and the interface conversion apparatus comprises:
• a conversion component, a control component, an impedance matching component, and a switch component;
• a first port of the conversion component connected to the two-wire communication system, a second port of the conversion component selectively connected to the control component or an input end of the 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;
• when the switch component is switched to connect the second port and the control component, the control component configured to output a test tone signal, detect a first voltage level of the output end of the four-wire communication system, and determine a target impedance parameter of the impedance matching component based on the first voltage level;
• and
• when the switch component is switched to connect the second port and the input end of the four-wire communication system, the conversion component configured to implement a signal conversion between the two-wire communication system and the four-wire communication system.

An echo cancellation method, performed by a control component in an interface conversion apparatus, wherein the interface conversion apparatus further comprises a conversion component, an impedance matching component, and a switch component, a first port of the conversion component is connected to the two-wire communication system, a second port of the conversion component is selectively connected to the control component or an input end of the four-wire communication system through the switch component, a third port of the conversion component is connected to an output end of the four-wire communication system, a fourth port of the conversion component is connected to an output end of the impedance matching component, and the impedance matching component is connected to the control component, and the method comprises:

• outputting a test tone signal when the switch component is switched to connect the second port of the conversion component and the control component;
• detecting a first voltage level of an output end of a four-wire communication system;
• and
• determining a target impedance parameter of the impedance matching component based on the first voltage level.