If program Retevis RT73 in software, you'll find the Rolling Code item behind the Radio ID item. if you check the Rolling Code item, you can program a unique ID to identify your radio. The other radios can use that ID to call you. For example, to initiate a private call or send a text message. ID editable range, Max: 16776415, Minimum: 1, Increment: 1.
If we have four cars with four Retevis RT73 that needs to be programmed to make QSO together, we only need to check the Rolling Code item, then write into four Retevis RT73 in turn. such as the ID of the first is 4604225
Then the ID of the second is 4604226, third is 4604227, fourth is 4604228. We only need to connect to next radio to click write directly.