The reason why the walkie-talkie can transmit but can't receive is that the auxiliary audio is set incorrectly. Continuous voice control mute system, commonly known as subaudio, is called subaudio because its frequency range is lower than standard audio.

Sub-audio setting problem

Sub-audio is a technology that attaches a frequency lower than the audio frequency (67Hz-250.3Hz) to the audio signal and transmits it together. Check the transmitting and receiving frequencies and sub-audio;

Intermediate frequency demodulation

After the interphone demodulates the received intermediate frequency signal, it filters and shapes the secondary audio signal, and then inputs it into the CPU, and compares it with the CTCSS frequency set by this machine, so as to decide whether to turn on the mute.

Physical damage to hardware

It is also possible that the interphone hardware is physically damaged, and it is necessary to contact the after-sales department for detailed inspection.