Scanning: a way to listen to all channels. By pressing the special key, the receiving circuit receives the signals in the channels one by one in a certain order for a certain period of time. Monitoring: a monitoring method for receiving weak signals. By pressing the dedicated key, the channel for receiving the signal is forcibly connected, and the operator can distinguish the sound in the speaker with his ears to achieve the purpose of listening. Priority channel scanning function: scan the set priority channels preferentially during scanning. Delete/Add Scan Channels: Delete or add channels from the scan list. Voice Control (VOX): After activating this function, you can start the transmitting function directly by voice without pressing PTT key. TOT:Time out Timer): This function is used to limit the user's overtime transmission on a channel, and at the same time avoid the damage to the walkie-talkie caused by long-term transmission. Buttery Save: In order to save electricity and extend the standby time of its walkie-talkie, the walkie-talkie does not transmit, receive or press buttons for a period of time, and works in a way of turning off for a period of time and turning on for a period of time. This way is called saving electricity. High/low power selection function: This function allows users to select high power or low power according to the actual situation. Busy channel locking function: When using this function, users are prohibited from transmitting signals on busy channels. Quiet level: the noise intensity in the received signal has a right-to-right relationship with the signal intensity. The stronger the signal, the weaker the noise. The maximum noise and minimum noise are divided into several levels, each level is called a level, and the number of levels is called the quiet level. Users can choose according to the actual situation. CTCSS/CDCSS function: Use this function to avoid receiving irrelevant calls. Dual-tone/dual-tone multi-frequency selective calling function: use dual-tone or dual-tone multi-frequency signaling to select and call the corresponding interphone. Frequency reversal function: When using the frequency reversal function, the transmitting frequency and receiving frequency of interphone will be interchanged, and the set signaling is the same. Intercom: When using the intercom function, the transmitting frequency of the intercom is the same as the receiving frequency; The transmission signaling is also changed to be the same as the reception signaling. Automatic transnational function: When the intercom receives a correctly coded call, it will send a signal to the caller and automatically answer the call. Emergency alarm: Press the special alarm key, and the intercom will give an alarm sound at the maximum sound or send a predetermined alarm code to other mobile phones. Key lock function: Use this function to prevent key misoperation. Cloning function: This function allows the data in one walkie-talkie to be copied to other walkie-talkies of the same model. Modulation: One or several parameters of the modulated signal are used to control the change of carrier parameters. According to different control parameters, modulation can be divided into amplitude modulation, phase modulation and frequency modulation. Audio: refers to the voice frequency of human speech, usually refers to the frequency band of 300HZ-3400HZ. Carrier wave: the carrier of voice digital signals, signaling and other useful signals, as well as high-frequency electromagnetic waves that are easy to transmit. Modulation uses one or several parameters of the modulator signal to control the change of carrier parameters. According to different control parameters, modulation can be divided into amplitude modulation, phase modulation and frequency modulation. Channel and channel spacing; Channel refers to the frequency value occupied when transmitting and receiving. The frequency difference between adjacent state channels is called channel interval. CTCSS: Continuous voice control squelch system, commonly known as incoming sound, is a technology that attaches frequencies lower than audio (67HZ-250.3HZ) to audio signals and transmits them together. Because its frequency range is lower than standard precision audio, it is called incoming audio. After the interphone demodulates the received IF signal, it filters and shapes the input audio signal, and then inputs it into CPU, and compares it with the CTCSS frequency set by this machine, so as to decide whether to turn on the mute. DTMF: Dual-tone multi-frequency, composed of high-frequency group and low-frequency group, each group has four frequencies. The high-frequency signal and the low-frequency signal are superimposed to form a combined signal, which represents a number. DTMF signaling has 16 codes. Using DTMF signaling, you can choose selective calling.