How to make a call between HD1 walkie talkie and RT85 walkie talkie？

Retevis HD1 walkie-talkie is a digital mobile radio, and Retevis RT85 is an analog walkie-talkie. How can digital mobile radio and analog two-way radios make calls?

First, HD1 walkie talkie and RT85 walkie talkie must be in analog format at the same time.

Second, the channels of HD1 walkie talkie and RT85 walkie talkie remain the same.

Third, the transmitting frequency of HD1 walkie talkie is equal to to the receiving frequency of RT85 walkie talkie.

Fourth, the sub audio of HD1 walkie talkie is equal to the sub audio of RT85 walkie talkie.

If the above four conditions are met, the digital mobile radio and analog radio can talk.