Line card, related apparatus, and control method

A line card, comprising a battery interface, a voltage conversion circuit, a plurality of holes, a connection cable, a speaker, one or more power amplifiers (PAS), and a controller, wherein:

• the plurality of holes are located between the speaker and the battery interface, two ends of the connection cable are respectively connected to the battery interface and the voltage conversion circuit, the connection cable runs through a gap between the speaker and a first hole of the plurality of holes, and the first hole is a hole closest to the speaker among the plurality of holes;
• the battery interface is connected to the voltage conversion circuit, and the voltage conversion circuit is connected to the one or more PAS;
• the battery interface is configured to connect to a battery, to supply power;
• the voltage conversion circuit is configured to convert a voltage to supply power for the one or more PAS;
• a first current on the connection cable corresponds to a power supply voltage or a power supply current of the voltage conversion circuit when supplying power;
• the one or more PAs are configured to amplify a radio frequency signal;
• and
• the controller is configured to control, when the voltage conversion circuit supplies power for the one or more PAs, a current value of a first current, so that the first current reduces a magnetic coupling problem of the speaker.