1750Hz, scientific name: transit pilot frequency, single tone pulse (signal), belongs to an audio frequency.
1750Hz is used to connect to the repeater. To transmit the 1750Hz function of the walkie-talkie to the repeater, you can turn on the switch for connecting the walkie-talkie to the repeater, which is equivalent to an activation command.
To give an easy-to-understand example, if you want to enter a high-end dinner party, you must have an invitation to enter. The 1750HZ of the walkie-talkie is equivalent to an invitation, and the encryption function of the repeater is equivalent to a dinner party, and the 1750HZ function can be used to unlock the repeater to make a call.
When a repeater in European countries is online, an audio call signal is required, which is a 1750Hz audio pulse. Only the 1750Hz pulse audio can be used to turn on the repeater. 1750Hz is the most common tone pulse, and some will also be seen, but not commonly used, for example, 1000Hz, 1450Hz, 2100Hz.
Some repeaters need the walkie-talkie to send a 1750Hz tone to connect the walkie-talkie to the repeater.
If the walkie-talkie does not have a 1750Hz tone, it cannot be connected to the repeater, but if the repeater does not require a tone, then this function of the walkie-talkie is useless.
Which Retevis walkie-talkies have 1750HZ function?
Retevis walkie-talkies basically have 1750 functions, and some walkie-talkies cover four types of single-tone pulse signaling, such as Retevis RT23, Ailunce HD1.
How to operate 1750Hz?
Most of the other walkie-talkies are implemented by customizing the side keys, which support manual settings. We can directly define the side key 1750Hz function through the walkie-talkie keyboard. If it does not support, we can set the side key 1750Hz function through the software.